No start. Have installed new coil (tried 2 different new coils), new plug, cleaned engine ground, disconnected switch. Occasional visual spark with plug grounded on engine. In-line spark tester does light dimly. Sanded magnet contacts which are rust free. Checked spark arrestor which is clear. Also has new carburetor, gas lines, primer bulb (carb kit). Any other ideas would be appreciated. Thank you.
SRM trimmer no/weak spark
- Thread starter Joe200
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You will not always be able to see the spark.
Squirt a little fuel mix in he plug hole and try starting. IF starts then it is a carb issue. If it don't then it is likely a compression problem. You must have at least 100 psi for a two cycle to start.
Squirt a little fuel mix in he plug hole and try starting. IF starts then it is a carb issue. If it don't then it is likely a compression problem. You must have at least 100 psi for a two cycle to start.
bertsmobile1
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I use a red inline spark tester because the sparks on hand helds that doo near 10,000 rpm is quite weak at cranking speeds
Trying to see a tiny blue spark on a machine that is bouncing around all over the place is not easy at the best of times .
he voltage from a permenent magnet magneto is proportional to the speed the magnet passes the coil legs
If it is optimised for 10,000 rpm it will be very weak at 500 rpm cranking speeds .
SO I do 2 rests.
1) Tester on the spark plug with plug installed
2) tester grounded to the block, plug installed
IF I get a significantly better spark in test 2 the magneto is on the way out & gets replaced .
Now here is the crunch.
Most home owners pull the plug and ground it to the engine when looking for a spark
Doing this will cause the engine to spin at nearly doubls the speed that it does plug in
So they see a fat blue spark in te test, but with the plug in the spark is just too weak to do the job & she will not start, or fire a couple of times but not catch & run .
Trying to see a tiny blue spark on a machine that is bouncing around all over the place is not easy at the best of times .
he voltage from a permenent magnet magneto is proportional to the speed the magnet passes the coil legs
If it is optimised for 10,000 rpm it will be very weak at 500 rpm cranking speeds .
SO I do 2 rests.
1) Tester on the spark plug with plug installed
2) tester grounded to the block, plug installed
IF I get a significantly better spark in test 2 the magneto is on the way out & gets replaced .
Now here is the crunch.
Most home owners pull the plug and ground it to the engine when looking for a spark
Doing this will cause the engine to spin at nearly doubls the speed that it does plug in
So they see a fat blue spark in te test, but with the plug in the spark is just too weak to do the job & she will not start, or fire a couple of times but not catch & run .
bertsmobile1
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That is from sodium
People think that the spark itself has a colour but of course a spark is a flow of electricity which of course has no colour
What we see iis the ionization effect of the gasses the spark is traveling through and some times the colour of the material at the end of the spark.
And I did both flame chromotography and emmission spectrochemistry so man I have seen every colour spark that it is possible to make
People think that the spark itself has a colour but of course a spark is a flow of electricity which of course has no colour
What we see iis the ionization effect of the gasses the spark is traveling through and some times the colour of the material at the end of the spark.
And I did both flame chromotography and emmission spectrochemistry so man I have seen every colour spark that it is possible to make
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Bingo. That what had to tell the guy from Hawaii a couple years when his mower fell into his salt water pool. He had a nice orange spark but insisted his coil would be bad, It turn there was just too much water in the engine.
stihlmania
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It took 3 coils from Amazon to get the SRM 225 trimmer I was working on to run. Sent the 2 defective ones back….17 bucks for aftermarket versus 65 for Echo OEM coil. Guess what coils I will quote next job….?
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Learning...Going cheap is not always the best path. When you run a shop your time is just as important as parts cost. And most 2 cycle handhelds have to be taken half apart to access most parts. But it can just as bad on some rider engines like the JD 737 that a lot have to come off just to get to the carb or a Gravely ZTR where to change the starter solenoid the engine has to be unbolted just to access the starter solenoid. Don't want to do it but once if possible. OR a half day is wasted.
And after all the Summer rush I finally down to 7 major jobs in the shop. Finish pulling a KT740 for rebuild. Short blocking it. A royal pain to get the PTO off yesterday and the engine drive pulley is still stuck on. Bad Boy didn't use any anti-seize so things are rusted on that 2017 ZTR. I would not being doing this job if the customer didn't forget an important part of an oil change. The oil.....Both rods snapped and large hole behind the starter. Two weeks to get a short block vs 12-18 weeks for a new engine.
And after all the Summer rush I finally down to 7 major jobs in the shop. Finish pulling a KT740 for rebuild. Short blocking it. A royal pain to get the PTO off yesterday and the engine drive pulley is still stuck on. Bad Boy didn't use any anti-seize so things are rusted on that 2017 ZTR. I would not being doing this job if the customer didn't forget an important part of an oil change. The oil.....Both rods snapped and large hole behind the starter. Two weeks to get a short block vs 12-18 weeks for a new engine.