Hi, getting a little frustrated. I have had this saw posted for sale for a while, been sitting unused for a few months. I recently rebuilt the carb, new fuel line and spark plug, just today I regapped the coil, it was a little too close. I can't get it to start, all I can get out of it is a backfire. Does this saw have a 2 piece coil? Not sure what to do next, except to maybe drop the price and sell it as non running. It's a really nice looking saw with 170# of compression/
shindaiwa 488 backfires, won't start
- Thread starter david newbie
- Start date
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Generally in a 2 stroke, backfiring it is ignition related either timing through a sheared key or a defective coil.
Easy test for a sheared key is to check the position of the coil relative to the magnets in the flywheel. When rotating the engine in it's normal direction, they should line up just before the piston reaches TDC. It's a rough test, a more accurate one requires the use of a timing light and a reversible drill to rotate the engine.
I removed the flywheel, looked at the key and it seemed ok to my poorly educated eye. Cleaned under there and put it back together. Now it starts and runs. no idea why that would have fixed it, except I think maybe it's a little scared of me now ( kind of like taking your dog to the vet)
New resistorless spark plug helped.
I was not able to locate one. Where did you get it?
Advance Auto...they cross-referenced the NGK to an Autolite they had. It seems to work. More testing soon. Probably needs a coil, but maybe this will get me by for a while. We shall see. I figure there is nothing to lose, it had stopped running well anyway. It had intermittent problems, probably coil I think at this point.
That saw fires up great now with the new spark plug, even with the choke now. No flooding...no backfiring. It is really awesome with great power and sounds great. Thank you. I know what to do now to address those strange issues now. Apparently the coil is a bit weak, but with the non-resistor plug it goes right along. We will see how long I can milk it before needing a proper coil job.
Husky77
ArboristSite Operative
I would put my money on the flywheel, if the key has sheared that will do it. Maybe someone had it off and either messed up putting it back on or the nut has come loose.
How would that explain flawless running with the other plug?
Husky77
ArboristSite Operative
some you win some you loose, always start with the basisc, like.... fuel-plug! safes a lot of time frustration and hassle. Glad its sorted ;-)
