Need Help With 032 AVE

[Jungle Jim]

Have an odd problem with my 032 that I'm stuck on at the moment. Recently rebuilt the carb, new plug, it ran good as new. Ran 5 tanks of gas through it, [premium with Stihl 50:1] worked great. On the next tank it started, ran a couple seconds, died, then wouldn't start again ... ever! I found that the polyurethane foam element in the fuel filter had disintegrated, gotten into the carb, and totally clogged up the intake right beneath the needle. OK, that would surely be a problem. Cleaned everything up, rebuilt. Still no start and fuel flooding the air filter. Carb adjustments were OK. Then I discovered it also had no spark and I was probably just flooding the carb trying to start it. I've been through the entire electrical system and can't find anything wrong with it. The coil tests good @1.2 ohms primary, around 9k ohms secondary, the switch is good [and not upside down], the grounds are good, wires are good, magneto set at .010", everything is clean, and the plug wire has continuity. Both old plug and a new plug tried. Meter shows I do get voltage when pulling the flywheel, although I can't read just how much. That leaves the ignition module, which is aftermarket - think Stens - but it does have resistance across it so is not shorted or open. In a dark room, no spark at all. It did sit a while before I realized there was no spark. It seems highly unlikely that both fuel and spark would fail simultaneously - 2 different systems - but that may be the case. First thought is fix the spark and the carb flooding should resolve by itself. Am I missing something here? Thanks Guys!

 

[JJoe_257]

It's really rare for two separate systems to fail at the same time, but I think you've done a good job narrowing it down!
Given all the troubleshooting you've done, yeah.. it's very likely that your aftermarket ignition module has failed.
Even if it shows some resistance, these modules can be finicky and fail after a short time.
But before you buy a new module, double-check your magneto gap again and also make sure the wire from the module to the spark plug is seated firmly at both ends.
If those look good, replacing the module should get you back up and running!

 

[Jungle Jim]

Thanks JJoe, is the plug wire on the OEM coil removeable? It rotates freely in a connector that suggests it IS but I don't want to pull on it hard and break something. There is conductivity through the plug wire or I woulldn't get 9k ohms reading on the secondary.

Also I'm thinking it would be instructive to measure the output voltage of the module, though that's hard to do accurately with a digital multimeter.

 

[Leon Couper]

Just a thought, check the wire from the switch is not pinched and shorting out.
Silly little things like that can cause no spark.

 

[STIHLTECH]

The plug wire spins freely? At some point it should tighten.
Is this a separate small module with 2 wires? Yes, they do fail quickly sometimes. Check wiring and ground TO CASE. Been there, done that
Do we check coil ohms in the shop? Nope.
Check spark with a large gap to a good ground.
Make sure switch and coil wire are not shorting. See how they are routed on the 032? Known issue.
Make sure there is a ground from the coil laminations to a cylinder fin. Clean mounting screw pads to cure.
If all of this checks out. you have a bad coil/module.

 

[Jungle Jim]

Thanks Stihltech. This does provide a clue. I don't know for sure how the plug wire / boot are supposed to work. As stated, it was rotating in its "socket" at the coil end and I did not realize it could be tightened, nor did I want to fool with it and possibly break something. In spite of it being loose, I was still able to measure coil secondary resistance from the spring cap in the plug boot through the secondary coil to ground, around 9k ohms. I've taken it apart again and it does indeed tighten up and seat with clockwise rotation - the measurements are still the same thru the circuit @9k ohms. Looking into the coil interface with the wire completely removed, I see a central pin sticking up 1/2" or so and threads on the ID of the fitting. Looking at the coil end of the spark plug wire, I see a copper wire inside a heavy jacket that makes compression contact with the central pin. The plug end of the wire (heavy stiff grey color OEM) has a coil spring fitting to the plug. The plug wire has conductivity end to end. Long story short, it seemed to make contact even though the plug wire was about a turn loose (not bottomed out) and I have remedied this issue. Still thinking it's the ignition trigger module and I'm waiting for delivery on a new one. FYI, the magneto / coil / wire,etc are OEM. The saw was electronic model when new. The ignition trigger has been replaced a couple times and is a single wire, small silver brick about 3/4" square x 3/8" thick, that bolts directly to the coil mounting on the block, not sure on brand. Everything else you mentioned checks out.

I'm thinking I may have unintentionally damaged the trigger module by cranking the engine without the plug connected. There's an electrical effect known as "inductive kick" - that voltage generated needs to go somewhere else if there's no spark plug, and it just might go through the trigger module back to ground. Diodes don't like this and you should not crank an engine with the plug disconnected!

Any other thoughts would be appreciated and thanks to everyone who has replied. I'll report back when I get the new trigger module, etc. --JJ