Adjusted the coils and valves. I have spark but not sure how strong the spark should be, for comparison. Battery is charged and engine spins well, plenty of compression. Fresh gas and cleaned carb. I even sprayed a bit of starter fluid in the cylinders after checking for spark. Would not even fire once. What else should I check?
2015 Toro v-twin won't start
- Thread starter dtestin
- Start date
Check to see if you’ve given us enough information to help you. Do you think if you told us the model and serial numbers of the unit it would help us? What about the make, model and serial numbers would give us an idea of which of the hundred possible engines you have? Was this problem ongoing or just happened recently? We are not standing next to you, with a strong drink in our hand, to see what you have!! You need to help us before we can help you.
Here is additional information Toro MX4250 74760 315002651 June 2015 24.5hp 708cc Loncin 2P77F engine. It had been hard starting and occasionally backfiring when starting last year. It did not want to start when hot. I had adjusted the valves last year and that did not seem to help. I cleaned the carb and adjusted coil gap a couple weeks ago when I got fresh gas. I do have spark but I am not sure if it is strong enough - nothing to compare it to. I even sprayed a little starter fluid in the cylinders after checking spark and did not get ignition. Battery seems to be fine and was charged over the winter. How strong should the spark be?
Spark is spark, trying to explain how it should look is impossible. From what You tell us I would recommend you check valve clearance. I’ve attached a Loncin service manual which should help you out. https://www.toro.com/getpub/117255
Midnight_Rider
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Place engine in a fairly dark area and spin it over while grounding the spark plug to the engine..You want a bright blue colored spark,not a weak white or yellow colored spark.. you need at least 90 psi to start an engine and it to run well.. If you have good enough compression,blue spark,good fresh fuel and it's making it into and out of the carb along with clean air and still doesn't start then I'd check the flywheel key to see if it's sheared and spun the flywheel making the timing so far off..
If I don't have that bright blue spark, does it mean I likely need new coils? It seemed at least one of the coils might have been touching the flywheel before I adjusted them. Would that damage the functionality of the coil?
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If you see the spark it usually strong enough. Trying going the color is going cause problems as different environments will produce different color sparks depend the air chemical make up. The test for how strong it is if it can jump a .166 spark gap it is strong enough.
Have checked for a sheared flywheel key? Kinda rare on riders but if someone previously had the flywheel off they might have not torque it to spec.
You got to fuel, air, compression, and spark at the right time.
Have checked for a sheared flywheel key? Kinda rare on riders but if someone previously had the flywheel off they might have not torque it to spec.
You got to fuel, air, compression, and spark at the right time.
Just running a compression test tells you nothing of condition of the internals. You'd need a differential tester to determine where the compression is going after the valves close. Adjusting a poorly seated valve only gets you a properly adjusted valve that won't hold compression. All of this is just to say check valve face condition. If you have used ether and gotten nothing that's pretty telling as simple static discharge will light up ether immediately even at concentrations of just 1.9% by volume. The prior hard starting indicates a progressive issue.
Did you try a new plug for
and giggles? Sometimes it works...Midnight_Rider
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Usually it doesn't kill the coil if it touches unless the flywheel grinds the coils face then it could.. you can use a multimeter to test the coils,youtube has many tutorial videos on testing.. Have you tried a new spark plug as I've seen instances where the plug would fire outside the cylinder but wouldn't fire off fuel when installed... A blue spark is ovtained when all electrical components are in their best shape and the engine is making good strong spark and is what I always look for when troubleshooting..