Weak Spark On Small Engine







A vacuum leak on a fuel injected engine will cause high idle. Keep the engine at least 1 meter (3 feet) away from buildings and other equipment during operation. Are you having trouble getting your engine to start? If so, you likely have a problem in your ignition system. 8L Ford F150 (or E150, Bronco, Crown Victoria, Grand Marquis, etc) is fried and causing your vehicle to NOT START or not the cause of the problem. With help from the spark plug experts at NGK, we’ll teach you how to diagnose minor tuning issues or potentially major engine problems by examining your spark plugs. I swapped the intake the other day. The ignition coil must then disabled or the high tension lead grounded. Your engine running lean is always a symptom of another problem - it could be a dirty MAF sensor, a damaged oxygen sensor, or damaged fuel injectors. Engine start with a weak spark. How to Diagnose a Loss of Spark in Your Car Engine. Evident is the "inverted U" characteristic of measurements made on actual spark igni- tion engines [3,4,8]. Verify that spark plug is correct heat range and. You have removed the spark plug and it is wet with gasoline, the engine won't start and no other checks have been made. Whatever the case, if the battery is weak, it puts out less of a spark in the combustion chamber. So at low engine speed, spark energy was quite weak; in some cases it was too weak to start the engine. Hi and welcome, I'm guessing you already disconnected the kill switch but thought I'd throw it out there. I checked the compression on this 2 stroke and got about 40 to 45 psi that's too low, right? I'm thinking I'll pull the engine apart and check the ring Any thoughts?. This is the "miss" part. This is coming from someone who has rebuilt way too many motorcycle carbs and a couple small engine carbs. Spark plugs that haven't been changed for a long time can become one with the cylinder head. The ignition coil must then disabled or the high tension lead grounded. An ignition system in a small engine produces and delivers the high-voltage spark that ignites the fuel-air mixture to cause the combustion. How to Fix Old-School Ignition Points: DIY Auto. Enough water can cool the engine to a point where the water cannot boil away. if any spark at all is created coils are good,this particular machine has no ignitor. This is not much of a big deal with small two and four stroke engines but it IS a big deal with a large. It would operate fine forward, reverse, and even a lash up with the remote. 1987 notch 5. Notice: Undefined index: HTTP_REFERER in /home/baeletrica/www/rwmryt/eanq. Have a 16 Hp Kohler engine. You don't want to have a tank of fuel nearby (if there is a small engine fire, having a tank of gasoline, even a small 1-gallon tank, could result in a much larger fire). net Sponsored Events Classifieds. A clean, white insulator firing tip and/or excessive electrode erosion indicates this spark plug condition. If the coil fails completely, it will leave the engine without spark, which will result in a no spark, no-start condition. Make sure you unplug the old ignitor if you use the new style. Disconnect negative (-) battery cable. With a spark plug tester hooked up during the times that it won't start, I see only a weak spark. The line of MSD 6-Series Ignitions are the most popular aftermarket ignitions in the world due to our race-proven performance on the track and our reliability on the street!. It used to be either spark or no spark, but I have seen more and more with weird "some" spark issues. With most gas engines for boats it'll be hard to see the spark in daylight, one of the. If you still have no spark replace the ignitor with a known good one, or use the 97-UP coil with built in ignitor. With engine rotated to TDC (0 degrees) on the firing stroke of Cylinder number 1, ignition switch ON, turn the distributor until the timing light flashes. If you don't have a helper, you can do it this way: Pull the hi-tension lead out of the distributor cap and hold near ground. this forum is probably old and no one is still watching this post but my 97 jeep grand cherokee was just doing what everyone is complaing about and i had replaced all the same stuff. Your engine's exhaust contains poisonous carbon monoxide. If the spark is yellow and weak, or there is no spark then the first thing to do is try a new spark plug. Having stripped the genny apart I have found what looks like a small coil pack (centre of photo) with a long thick black lead that goes off to the spark plug. So I picked up a "new" but dead leaf blower yesterday. A weak reading could indicate a magnet that has lost some of its strength. What we do is remove all the spark plugs from the engine, set up the points, turn the key on and crank the engine while adjusting the point dwell. Test the safety switch. Diagnosing a balky engine is not difficult but a step-by-step methodical procedure will make it a lot less traumatic. If the engine is old enough to have points, a dirty or worn set of points and condesor can cause it. Engine flooded: Fuel level too high. Orange and yellow come from particles of sodium in the air ionizing in the high energy of the spark gap. Cold ambient air temperatures 9. If the ignition coil is not working, the existing spark plug is uneven, which causes uneven firing of the pistons. It doesn't have an air filter though. Run a cylinder compression check by removing the spark plug and installing a small engine compression gage. Fuel tank suction. Small engine very weak spark - Answered by a verified Technician We use cookies to give you the best possible experience on our website. i have a briggs and stratton 650 series quantum engine, only 2-3 years old, the engine would start randomly/once in awhile and other times would not start, this has been occuring for about 6 months, when the engine DOES start it will run fine till i shut it off, then will not start again until it has fully cooled down (the next day), i have been slowly trying to isolate the problem, the carb. Check out the images below, courtesy of NGK Spark Plugs, and get ready to do a little light reading the next time you pull your spark plu. LA V-8 Engines. Watch the spark tester or spark plug, looking for a spark between the electrodes of the tester or spark plug. by Kyle McFadden. An engine not getting the right amount of fuel, air, or a proper spark will exhibit a loss of power. What's confusing to me that the motor never tries to die, as I would expect if there was an issue with grounding. Replace with new plugs of the same heat range. While a stator is dying, it can produce a weak spark, causing the engine to miss or run poorly. I change the coil if I have a GM engine that won't start in the cold and has no spark. Open shutoff valve. However, they are talking about small air cooled engines, and are using a specific Briggs and Stratton spark tester with a fixed gap for. Then consider registering so that you may make posts, and view the additional content available. Depending on how old the engine is (really more how many hours the engine has been run) the magneto could be weak. Attach a stroboscopic timing light to the spark plug wire of Cylinder number 1. Chris you were getting no spark - not weak spark I suspect the ECU not triggering a spark rather than the coil. When you are diagnosing a small engine with a no start condition there are three basic things that can cause this: Air / Fuel Mixture Electrical or Spark Compression. Idling the engine during a long taxi and waiting for takeoff with the mixture in the full rich position results in carbon deposits on the spark plugs and the engine will start to run rough when power is applied. Retroactively referred to as the "Generation I" small-block, it is distinct from subsequent "Generation II" LT and "Generation III" LS engines. Some people often prefer to take their vehicle to a professional for. With a number of frequently asked questions, we'll guide you through easy at-home steps to troubleshoot your MTD outdoor power equipment from the comfort of your own garage. You have a defective coil and should replace it (B). On engines that don't have that access, you need to be a little more creative. Will not start. Check for spark with a ZAT 4 tester with plug installed, if no spark retest with new plug. ) - (Added 10/25/17) Need to rule out all possibilities first. It isnt a loud pop and it doesnt pop everytime I go down the track, just every now and then maybe 1 out of every 3 passes, but when it doesnt pop it doesnt go any faster or slower, but when I used to turn it 7000rpm(before I actually found out my motor peaks at 6400rpm) it used to pop. What causes weak spark besides bad Magneto? - Answered by a verified Technician Small Engine. Sounds like you sanded the coil poles, that should not have an dramatic effect on the spark. fumes, and never run the engine in a closed building or confined area. I can't even get it to pop,when I look at the plug its wet so it getting gas. I have to spin it pretty fast with drill to get a weak spark and no spark when I pull by hand. Your engine's exhaust contains poisonous carbon monoxide. The compressions system is made up of valves, Piston(s), Cylinder(s) and rings that control how the air and fuel vapors move through the engine. The engine will appear to stumble for a brief period of time and then regain its pace. You have a defective coil and should replace it (B). That just confirms that the spark plug fires in open air. You can waste hours of your time with Inline testers they do not accurately check the spark plug. My old Echo hedge Trimmer won't start this year. Check the rotor for damage and make sure the center electrode in the distributor cap is intact. Blue spark is cold in comparison to ultra-violet. Must-have diagnostic tool for any engine with a spark plug When engine won't start, gives instant answer to 'does it have spark?' Turn the engine over - if ignition is being sent to the cylinder, light in tester glows Simple to use - just remove rubber boot from spark plug, insert tester & place tester boot on plug. Engine failure will result when the coil totally fails. As the engine speeds up, centrifugal. No spark is one of the most common reasons why your engine will not start. Spark Arrestor: A spark can exit the exhaust port of a small gas engine, potentially starting a fire on nearby combustibles. Inspect the porcelain of the electrode for cracks, chips or burn marks. When a signal is received by the trigger pickup passing over the flywheel magnet, the CDI will discharge the stored energy into the wires leading to the ignition coil. A small engine is much like a larger engine in many respects. I presume you will be changing the exciter coil at the first instance. Replace the spark plug(s) if. If you have a "Check Engine" light, your car's computer is storing information about what problem was detected. the mag would give a very. In engines of medium to high compression this kind of voltage is necessary to reliably arc across the gap on a spark plug and make enough fire to ignite the fuel/air mixture in a cylinder. A spark should appear on the hooked wire of the spark plug. Changed starter igniting unit and spark plug to brand new, no results, nothing changed. I have suddenly developed a weak spark and now it wont start. Run a cylinder compression check by removing the spark plug and installing a small engine compression gage. Briggs And Stratton 19. Your engine idles when it is a stationary and in this position the engine normally produces around 1000rpm. No flash means either a bad coil or a bad coil control circuit. Check engine control systems with a scan tool. 140 psi comp, piston looks ok, spark plug is wet with fuel. MANIFOLD AND CARBURETOR ASSEMBLY. If you still have no spark disconnect brown wire from mounting bolt on rev limiter and tape it so it doesn't touch metal on engine. A spark plug (sometimes, in British English, a sparking plug, and, colloquially, a plug) is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air mixture by an electric spark, while containing combustion pressure within the engine. Whatever is on your mind there. My buddy has a 2000 (i believe. I upgraded my alternator recently from a single wire to the modern. How do you "tune up" a hard-to-start Craftsman 18" chainsaw as possible until it's out of warranty small engine. A spark should appear on the hooked wire of the spark plug. Building a Stroker Small-Block with LS-Like Reliability and complete ready-to-run HEI distributors that can be added to a high-performance engine that'll provide excellent spark energy and rpm. Engine failure will result when the coil totally fails. By following these. On all engines, severe vacuum leaks can decrease manifold vacuum, resulting in a rich condition. Learn more about small engines and shop for Briggs engine parts, generators & outdoor power products. The job of an ignition system is to generate the spark energy needed to ignite the air/fuel mixture in an engine's cylinder. ) Coil weak or intermittent - you should see 3/8" fat blue spark with a good coil 3. I ran a 12volt jumper from battery to the coil and still no spark. I'm no mechanic but I've done my share of won't start problem solving on small. That just confirms that the spark plug fires in open air. Check with your boat or small engine repair shop to see if the magnet can be recharged before replacing the magneto. If the magneto is generating the proper ohms, check to make sure the spark plug is working properly. When you are diagnosing a small engine with a no start condition there are three basic things that can cause this: Air / Fuel Mixture Electrical or Spark Compression. ) Spark at spark plug, but no start. To set the spark plug gap correctly, you need to use a spark plug gap tool. Spark plug cap not in good contact with spark plug. 5 hp Tecumseh horizontal shaft engine. I'm no mechanic but I've done my share of won't start problem solving on small. Whether it's your mower, tractor, or handheld equipment, P&P Small Engines is here to answer all of your MTD troubleshooting questions. If you do, your coil is fine. If you know the engine repair part you need, you can browse the list of all parts on the 128H02-0515-E1, or you can search by name or part description. Verify stop switch function. Your Engine just started acting up and you don't know what to do. Outboard engines, as with any internal combustion engine, require air, fuel and spark to maintain adequate combustion throughout the power band. Briggs And Stratton 19. Most of the four-stroke engines had a variable advance. Looking for Site or Help in how to test the Engine Rectifier, Stator, Engine Module and Digital Module. Ask Your Own Small Engine Question. - If there is no spark or weak spark (thin orangish spark) at the spark tester, there is an ignition issue. Kawasaki FE290D-CS22 4 Stroke Engine FE290D Exploded View parts lookup by model. When working on small engines, it's important that you use good judgement and take safety precautions. ( Direct ignition is used on this engine to significantly reduce this effect, but it still happens). Donyboy73 is The Small Engine Doctor on youtube. When diagnosing engine stumbling or misfiring, its often useful to gauge the intensity of the spark at each cylinder. Removed the starter and cleaned the flywheel magnets. Rusty armatures, and rusty magnets will affect spark strength. You can waste hours of your time with Inline testers they do not accurately check the spark plug. A small engine is much like a larger engine in many respects. The finale of this sermon is that spark plugs replaced at spring commissioning are cheap while get home under power insurance isn't. You have removed the spark plug and it is wet with gasoline, the engine won't start and no other checks have been made. Upon inspection I found there was no spark. Compression on all 4 cylinders are above 100psi. Incorrect amounts of air or fuel will cause the engine to run sporadically or not at all, as will a weak or improperly timed spark. FC420V sometimes doesn't start - weak spark? Hi - I am looking for troubleshooting guidance for a walk-behind brush cutter (~15 year old DR) with a Kawasaki FC420V AS-22 engine[1]. Acts like. Historically, American auto consumers turned their noses up at four-cylinder engines, believing them to be slow, weak, unbalanced and short on. If you get an 1/8" or so of spark, that should be enough to fire. What we will be doing here is troubleshooting these ignition parts. Most small lawn mowers, chain saws, trimmers and other small gasoline engines do not need a battery. Simple answer, increase the plug gap back to. • If carbon gets deposited over the spark plug then it causes hard starting of vehicle this result in weak ignition. There may be a fault in the computerized engine control system. Chrysler Engines, 1922-1998, by Willem Weertman: the last word in Mopar engines. 200 with over 7 millisecond spark duration but the combination of high cost and short spark plug life didn’t justify the results. SMALL ENGINE REPAIRSMALL ENGINE REPAIR 366 SMALL ENGINE TROUBLESHOOTING CHART Problem Possible Cause Solution Engine fails to start or is 1. With engine rotated to TDC (0 degrees) on the firing stroke of Cylinder number 1, ignition switch ON, turn the distributor until the timing light flashes. If you hear noises and suspect there is something wrong, you should head to your local engine repair service provider to get your engine inspected. That will cause the engine to flood when more mixture enters the cylinder; If the engine starts and then quickly dies out immediately, that's a good sign that your spark plug is shot. out put at the plug. This problem is clearly not just a Ford Triton problem. more air to reach the engine. It would operate fine forward, reverse, and even a lash up with the remote. by Vaughn Aubuchon: I grew weary of paying $300 over and over again for "new plug wires". Is full of electronics. Retroactively referred to as the "Generation I" small-block, it is distinct from subsequent "Generation II" LT and "Generation III" LS engines. Keep away from spark or other ignition source. Order Kawasaki replacement ignition coils here! Trust us for all your small engine replacement parts at competitive prices with flat rate shipping!. Explosive Gas!. Subscribe and connect with more than 23,000 other gas engine collectors and build your knowledge, share your passion and search for parts, in the publication written by and for gas engine enthusiasts! Gas Engine Magazine brings you: restoration stories, company histories, and technical advice. Basically, you need proper voltage to the coil and a good ground inside the dist for the point plate, along with a good ground path for the dist itself. If the ignition coil is not working, the existing spark plug is uneven, which causes uneven firing of the pistons. This is most common to happen on the intake seat. What to Look For. • If carbon gets deposited over the spark plug then it causes hard starting of vehicle this result in weak ignition. For maximum performance and engine life expectancy, we also recommend using STIHL HP Ultra 2-cycle engine oil. Have a 16 Hp Kohler engine. 2 Stroke Engine Troubleshooting - Spark. With ignition On, turn the engine pulley CW past the TDC mark. No-spark conditions can have a number of causes, but for starters, we need to know if we have spark when we crank the engine. Disconnect negative (-) battery cable. If you know the engine repair part you need, you can browse the list of all parts on the 128H02-0515-E1, or you can search by name or part description. Discussion about the “right” way to check spark plug resistance can go on until the cows come home. I an not getting any spark at all. Fuel is getting all the way into the carb so I took off the spark plug and tested it on the mojo's engine - nice big spark, but I have no spark at all on the generator. Once it's set, we lock them down and finish the tune-up. If one was clean on fould it is ignition. With help from the spark plug experts at NGK, we'll teach you how to diagnose minor tuning issues or potentially major engine problems by examining your spark plugs. I have set coil gap at. So here are some simple steps you can take to nip. Engine Will Not Start Spark No Spark Check for spark Spark Set proper point gap, check condensor and timing No Spark Replace spark plug Isolate engine from all equipment (disconnect wiring harness), repeat test Parasitic load too high Test coil for intermittent or weak spark Set proper air gap on external coil Check flywheel for correct key. This is called quenching the spark. If the spark is weak (should be strong blue spark) and the spark plug has been replaced then it's almost certain that the ignition coil is failing. 200 with over 7 millisecond spark duration but the combination of high cost and short spark plug life didn’t justify the results. Bad spark plugs, bad spark plug wires and a bad distributor cap are other common causes of rough idling. - Turn the engine over with the ignition switch at the helm and observe the spark tester. Weak ignition is often confused with a fuel problem since the two systems are codependent. Video tutorial on how to check the spark on a small engine such as a rototiller, lawn mower, garden tractor, weed eater, snowblower, boat motors, leaf blowers, chainsaws, generators, etc. Pulled the flywheel and cleaned the charging coil, checked and adjusted the spark plug gap, replaced both coils and the voltage regulator. One of the earliest signs of determining a weak coil pack is engine misfires, also known as "hard starting. The job of an ignition system is to generate the spark energy needed to ignite the air/fuel mixture in an engine's cylinder. If you get an 1/8" or so of spark, that should be enough to fire. Just as well as too much gap causing too weak of a spark. I have to spin it pretty fast with drill to get a weak spark and no spark when I pull by hand. why are my spark plugs getting soaked with gas - roll over engine and will not start, pull plugs and they are dripping with gas, after a few, engine not ev. No spark is one of the most common reasons why your engine will not start. Move the piston to the downstroke position (most distant position away from the spark plug) and knock off carbon deposits with a screwdriver. I've confirmed that I'm getting 12 volts to the distributor, but even the center wire off the coil only sparks a tiny bit when grounded to the block. I just rebuilt a Robin Eh29C engine out of a 97 EZ GO cart. MANIFOLD AND CARBURETOR ASSEMBLY. He provides his. And because spark plug health is directly linked to engine performance, it stands to reason weak or bad spark plugs lead to problems, be it issues with cold-starting or misfires during acceleration. Whatever is on your mind there. check spark. A new cde pty ltd spark tester kit ( see you tube demo) is the only accurate way to check your spark plug. No spark line. Video of the Day. I can't even get it to pop,when I look at the plug its wet so it getting gas. A good condenser minimizes this to a small blue spark but the points are sparking full-force with a yellow spark if the condenser is failing. In my case the engine was still under guarantee, however, when I initially checked the spark plug for a healthy spark, I was surprised how weak the spark was, which leads me to believe that the problem perhaps was the exciter coil, which I presume is part of the cdi package. This should remove the fuel from the spark plug hole that had seeped in during the flooding. Your lawn mower spark plug and ignition system are in order since they are keeping the engine running. Small Engine Flywheels - What They Are and What They Do; Photo 1. Basics to High Performance. In this article I'll show you a very simple, easy and highly accurate way to see if the ignition coil on your 4. the mag would give a very. The fix: If your vehicle has them, check and replace distributor cap, rotor, ignition wires, and spark plugs. Run a cylinder compression check by removing the spark plug and installing a small engine compression gage. A spark plug can deliver a weak spark (or no spark at all) for a variety of reasonsdefective coil, too much compression with incorrect plug gap, dry fouled or wet fouled spark plugs, insufficient ignition timing, etc. An engine not getting the right amount of fuel, air, or a proper spark will exhibit a loss of power. No spark line. 4 Reasons Why Engines Lose Power Over Time And How To Win Your Horses Back. I fed oxygen directly into the carb and cranked and got a weak pop-pop, too weak to start, but I continued cranking and the pop-pops kept getting stronger until it would run by itself. I used a test light at the points and the light flash's when the engine is cranking-so the distributor is good. Without proper uninhibited spark, your small engine powered equipment cannot run at its peak efficiency and power. You have a defective coil and should replace it (B). Determining why it won't start Think: FAST - Fuel, Air, Spark, Timing. Anything and Everything You Want to Know About Spark Plugs RPM situation where a weak spark could promote fouling. This is coming from someone who has rebuilt way too many motorcycle carbs and a couple small engine carbs. The coil can be ordered from the following link. Do not try to clean the. Check with your boat or small engine repair shop to see if the magnet can be recharged before replacing the magneto. For reference, see our spark plug gap chart below, this chart converts metric measurements to standard. Accidental starting can cause severe injury or death. How to Diagnose a Loss of Spark in Your Car Engine. If you own several small engines, it may pay to buy a tester To learn how to use it, read How to Test an Ignition Coil. Incorrect spark plug gap 8. Its simple, the magnets used are only effective to a certain range. I put in new fuel (50:1 mix) and replaced the plug. If no spark in either case, probably an electrical issue that is probably beyond your repair capability unless you have some mechanic experience. No-spark conditions can have a number of causes, but for starters, we need to know if we have spark when we crank the engine. An absence of spark will require replacement of the ignition coil. Jacked up back wheels after dropping engine back in and fired it up. I an not getting any spark at all. Compression ratio of an engine and the amount of fuel being delivered can have an effect on how well the spark plug fires. So you go out one morning and your engine will turn over but it won't start. A good condenser minimizes this to a small blue spark but the points are sparking full-force with a yellow spark if the condenser is failing. Use a hand held electric drill or an air wrench to turn the crankshaft at the magneto nut. Kawasaki small engine spark plugs gaps used on a variety of outdoor power equipment applications. Will a BRIGGS AND STRATTON 6. Make sure the switch is in the stop position, disconnect spark plug wire and remove plug. Try removing it at the coil and then check for spark. A new cde pty ltd spark tester kit ( see you tube demo) is the only accurate way to check your spark plug. Sounds like you sanded the coil poles, that should not have an dramatic effect on the spark. The ignition coil must then disabled or the high tension lead grounded. Your engine idles when it is a stationary and in this position the engine normally produces around 1000rpm. This is coming from someone who has rebuilt way too many motorcycle carbs and a couple small engine carbs. Found the fuel pump was weak and replaced it with a small electric pump from NAPA about $30. The complete ab-sence of a spark line means infinite resistance, like a disconnected or open plug lead. Your lawn mower might not be getting any spark because you could of sheared the flywheel key which will off set the timing then giving no spark to fire the engine. The Honda GX390 K1 is a 0. Once I used our small 2-cycle garden tiller. The ignition system consists of only solid state ignition module, flywheel magnets and spark plug. Attach a stroboscopic timing light to the spark plug wire of Cylinder number 1. A faulty ignition coil can also lead to a no-start condition. A narrow gap may give too small and weak a spark to effectively ignite the fuel-air mixture, while a gap that is too wide might prevent a spark from firing at all. Now I turn the key on until I hear it pressure up then bump the starter and it fires up. If you don't have a helper, you can do it this way: Pull the hi-tension lead out of the distributor cap and hold near ground. The compressions system is made up of valves, Piston(s), Cylinder(s) and rings that control how the air and fuel vapors move through the engine. 3-inch spark tester small engine tools feature a 3-inch nickel plated shaft and a 7-inch rubber boot and cable for versatility when working. I don't have a compression gauge, so that's why I don't have a reading, but I'll get it measured as soon as I can. A tachometer is required in setting the correct RPMs (normally 3,200 or 3,600 maximum for small engines) of an engine to prevent from over-revving and possible damage to the engine or dangerous flywheel explosion. Jumping ahead to 'so-and-so said it could be whatever' or just replacing parts usually just wastes your time and your money. So the weak spark is probably coming from somewhere else. 5: Detonation ("Spark Knock") Detonation, often called pinging, is nothing less than a series of small explosions that take place within an engine's combustion chambers. 7 cu·in) single-cylinder air-coolled 4-stroke internal combustion small gasoline engine with horizontal shaft, manufactured by Honda Motor for general-purpose applications, such as: pressure washers, tillers and cultivators, generators, construction or industrial equipment, water pumps. small engines 1-50. A tachometer is required in setting the correct RPMs (normally 3,200 or 3,600 maximum for small engines) of an engine to prevent from over-revving and possible damage to the engine or dangerous flywheel explosion. Engine flooded: Fuel level too high. Engine has a rough idle. Every engine needs three things to run and idle smoothly without stalling: a correct air/fuel ratio, sufficient idle speed for the idle load, and a good spark. He hired Champion to make insulators for him. Fuel shutoff valve closed. The spark generated by the spark plug might be too weak for igniting the air and fuel mixture that the mower's carburetor has delivered to its cylinder. By following these. Remove the top cover on the saw to expose the spark plug. Incorrect spark plug gap 8. I checked the compression on this 2 stroke and got about 40 to 45 psi that's too low, right? I'm thinking I'll pull the engine apart and check the ring Any thoughts?. What to Look For. How do i set the timing without a timing light ON A 1968 327 ENGINE?. Will not start. The trick is learning how to read your spark plugs. A spark plug is a fairly simple device. For example, instead of getting spark everytime the engine turns over,. I bought it about 2 months ago and it has worked flawlessly up till now. So the weak spark is probably coming from somewhere else. Fill tank with recommended fuel. If a lawn mower engine misfires, it could be an issue with the spark plug, valves, or ignition coil. Keep away from spark or other ignition source. Also, a decrease in power can be attributed to a failing coil, which will cause a low-spark intensity. It has a center electrode encased in a protective. Verify that spark plug is correct heat range and. in small 2-stroke engines. I twist the plug in the wire socket and get a single weak spark and then nothing. A vacuum leak on a fuel injected engine will cause high idle. Fuel line plugged or kinked. Engine Model Spark Plug FB460V BMR4A FC150V BP6ES FC290V BPR5ES FC400V BPR5ES FC401V BPR5ES FC420V BPR5ES FC540V BPR5ES FD440V BMR4A FD501V. of engine oil into cylinder(s).