Shindaiwa 500/451/415/416 ignition coil problem

[Jeff E]

I'm trying to find out the correct flywheel to ignition coil gap for a Shindaiwa 500/451/415/416 chainsaw (I have the 500). I read online it may be .012-.014” but not sure if its for those older models. I bought a used coil and exciter/pulser module on Ebay (he told me twice it tested good) installed it and set it to the above spec but still no spark. It looks like my original problem was actually that the cylinder fin melted into the spark plug lead and shorted it out, but the old coil doesn't work either with that gap. I have checked the on-off switch and grounds. Both coils read about the same on the primary and secondary windings on my multimeter (0.4,0.7 ohms and 5.1K, 5.4K ohms). I think my problem may be a flywheel to coil gap issue but I can't find the exact setting. Also - anyone know where I can find a service manual for a 500? Can't find it online.

 

[HarleyT]

If a business card gap doesn't give you a spark, then something else is wrong, not the gap.

 

[beaglebriar]

I have a manual for everything but the models you listed. Did you try pulling the wire off the kill switch? Also check all your wiring for breaks. Anywhere there's a kink in the wire grab both sides of it and pull real hard. If theres a break the insulation will stretch. Clean up all your ground connections and tighten them good. Check your flywheel key.

 

[Jeff E]

Thanks for the replies. I did use a business card to set the gap and pulled the wire off the kill switch. Is it possible the gap needs to be wider than the business card thickness? I will check the wires again for breaks and use sandpaper on the ground connections. I don't know what else to try. I'm spinning the flywheel with a battery powered drill (slow speed, in the correct direction). I believe at least one of the coils are good. Is there any kind of analyzer other than ohming it that will check the coil and exciter?

 

[Edge & Engine]

Correct gap is .014" And from the service manual (also attached):

(a) Check for proper function of the primary and secondary coils as well as the resistance using an ohm meter. The resistance of the primary coil should be 0.75 ohms +/- 5%. The resistance of the secondary coil should be 5600 ohms +/- 10%.
(b) If a small variation of the above is found, use an automotive type coil tester with a six volt range and check the coil itself. The spark should jump a gap greater than 6mm. CAUTION: When using the automotive coil tester, always use the six volt range and for less than one minute. (The coil will overheat if run for longer periods.)
5. The TCI unit is very reliable. If it appears to be out of order, replace with a new unit and check for proper function with the new unit installed.

 

[Jeff E]

Thank you very much Edge & Engine for the service manual for the Shindaiwa 350/415/450/500!! Hopefully others can find it on this thread. I searched for a while but could not find it with Google. Also thanks for the gap spec and the coil section from the manual. It looks like I'm in spec with at least one of the coils and I'm gonna check the wiring again carefully. I'm not giving up yet on getting the 500 running again as I really like the saw. If not successful, I'll be looking for a Stihl MS361, MS440, or MS460. Reliable Pro saws.

 

[Jeff E]

Correct gap is .014" And from the service manual (also attached):

I still have been unable to get any spark at all from the spark plug, using the spec in the service manual for the coil to flywheel gap (.014), and even trying smaller gaps (down to .007). I have gone over everything (grounds, wires, on-off switch, etc) and all is working properly. The replacement coil tested within factory specs with an ohmmeter. The original tested within service manual specs too. I am quite frustrated. I don't know what else to try except to replace the flywheel. Maybe there is an issue with weak magnets or pole reversal. A small engine repair shop said he had that happen with some Stihl saws. On mine, one of the magnets is quite strong while the others are definitely weaker. No sure if this is normal. Has anyone out there ever have flywheel magnet issues??

 

[HarleyT]

No!!

Get your money back from the guy on E-Bay! Don't waste your money on a flywheel!!!

 

[HarleyT]

Describe in detail how you are testing for spark.

You may be doing something wrong there...

 

[smokey7]

Your sure flywheel is turning counter clockwise? Also try and put a alagator clip from a jug fun to a coil bolt. I had it happen somehow the jug was no longer a good ground. One would think the ring/piston/crank/to bearings would ground it but I was proven wrong somehow.

 

[Jeff E]

HarleyT and Smoky7,
I'm holding a spark plug against the cylinder fins with the flywheel cover off and cranking the engine CCW with a battery powered drill on the flywheel nut. I have checked the grounds everywhere - on the Transistor Ignition Unit, magneto, cylinder fins, etc. Tried the cliplead between fin and coil pickup bolt. Disconnected the on-off switch. As I stated above, both the old and new coils are within specs for Ohms. Can't really test the Trans Ig. Unit though. One other thing - there are 4 embedded magnets around different parts of the flywheel - one has good attraction to a screwdriver while the other 3 are weak. Is that normal? Used flywheel $30 on Ebay.

 

[smokey7]

I keep hearing people talking bout flywheels being bad. I have never had one go bad. I have had them damaged, and had magnets rust off but not just getting weak.

 

[beaglebriar]

It the risk of sounding like an a$$ I'm going to have to ask a couple more questions here. Are you using a new sparkplug? If not start there. Did you get another TCI unit with the used parts you bought? If not then it would be a good indication that it is what's causing the problem. The flywheel likely has nothing to do with it. I have seen bad ones but not on a chainsaw. (Not saying it can't happen)

 

[Jeff E]

Not problem about asking the questions, I'm willing to listen to any suggestions. I have tried 3 different spark plugs, two for that chainsaw and one out of a trimmer. I am turning the flywheel CCW. I have tried two different TCI coils and two ig coils (original and replacement). Its odd I can't get any spark because I think the original problem was a plug wire that melted against the cylinder fin and shorted out the center conductor. I didn't notice that until I pulled out the coil to replace it with the Ebay one. The guy that sold me the coil and TCI is now sending a flywheel free to see if that's the problem. One question I just thought about - are the stacked metal plates on the ig. coil (that induces the current from the flywheel magnets) supposed to be isolated from the engine ground? The two screws that holds it in place contacts connects those plates and screws into the side of the cylinder. I don't recall any non-conductive washers to isolate the two from each other.

 

[Jeff E]

Not problem about asking the questions, I'm willing to listen to any suggestions. I have tried 3 different spark plugs, two for that chainsaw and one out of a trimmer. I am turning the flywheel CCW. I have tried two different TCI coils and two ig coils (original and replacement). Its odd I can't get any spark because I think the original problem was a plug wire that melted against the cylinder fin and shorted out the center conductor. I didn't notice that until I pulled out the coil to replace it with the Ebay one. The guy that sold me the coil and TCI is now sending a flywheel free to see if that's the problem. One question I just thought about - are the stacked metal plates on the ig. coil (that induces the current from the flywheel magnets) supposed to be isolated from the engine ground? The two screws that holds it in place contacts connects those plates and screws into the side of the cylinder. I don't recall any non-conductive washers to isolate the two from each other.

Ignore my last question, I just checked the service manual, its supposed to be grounded.