SUCCESS!!! Just repaired Stihl 045/056 Bosch electronic ignition!!!!!
- Thread starter foggysail
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Giles
ArboristSite Operative
foggysail--- I have three defective Stihl 201t modules. As some may know, Stihl screwed up when they made the 201t and many had defective coils--along with other items.
I have repaired/modified a few 201t but had to replace the coils.
Do you have any idea what their design flaw was and if your repair could be done?
I have repaired/modified a few 201t but had to replace the coils.
Do you have any idea what their design flaw was and if your repair could be done?
ILikesEmGreen
Another crazy Poulan Fan
Chase, what are your compression numbers on that saw? Low enough and it won't run right at all.
ILikesEmGreen
Another crazy Poulan Fan
If you've got strong spark and redone the fuel system, the only thing left is compression. Need all three to run a 2 stroke...
Have compression fuel and spark....dont have a way to measure the spark so not sure how strong it is. I've rebuilt lots of saws and 2 stroke dirt bikes....it has to be a problem with the ignition...anyone kniw what the resistance of the coil should be?
Are you sure the spark plug wire is properly set into the spark coil?
Giles
ArboristSite Operative
Thank you very much!
ILikesEmGreen
Another crazy Poulan Fan
It's usually "roughly" a matchbook thickness if i recall correctly...
Have you tried different carburetor settings? Mine won't even start if the L needle is 1 turn out. It has to be 3/4 turn out and it runs perfect. If my H needle is too low then it won't idle and will flood after I throttle it, if it's too high it won't start well. Possible air leak in fuel line? I had to goop some Threebond on the carburetor fitting last time I cleaned it because the fuel line wouldn't fit back on as well as it was originally. Also, check the muffler for carbon build up if you haven't already.
The gap is fixed and not adjustable. Now as to the coil, it could be breaking down and arcing internally although I doubt it. If it has an internal short......even between just two wires, the coil will not work at all, nothing, zilch, nada! There are two so called coils that are used in the ignition. The first is a charging inductor used to provide the storage energy into a capacitor.....yes, the capacitor that you changed.
Timing is determined by the rotating magnets which charge another but smaller capacitor up to the voltage needed to trigger an SCR (silicon controlled rectifier). When the SCR is triggered, it provides a current path for the charge on the energy storage capacitor to discharge. Current flows from the capacitor through one winding in the other "coil" which is not a coil at all but a high voltage transformer and back to the capacitor. The output from that transformer is the voltage that sparks the spark plug.
The other possibilities that can create trouble is the shaft key that positions the flywheel. If that got sheared or broken, the saw. The capacitor value is another. The cap used in your pictures looks like the right cap and it should be 1uf...most likely it is from looking at your pictures.
Please keep us informed as you continue to trouble shoot your problem.
Well so far ive got a new plug wire/boot and clip that will be installed tomorrow (working swing shift tonight) so we'll see where that gets me....its not a carb issue as I've had it running and tried making adjustments with no change it just misses REAL bad when throttled up (the only way itll run) and it doesn't idle at all. are there timing marks i can look at to make sure the ignition plate is where its supposed to be (i bought the saw in its current non running condition)
It is not a fuel problem, ive been back through the carb and its perfectly clean, metering lever set right, both l and h are 1 turn out which should get it running enough to fine tune. Installed a new plug wire/boot and clip still missing very bad....played with timing and got it to start a little easier but it still misses like crazy. Not sure what else to do here...in case anyone is wondering the compression is just fine...it is an ignition problem i know, just not sure what the next logical check would be.
The "fix" represents the one known high failure component in the ignition. So it is conceivable other components can/did fail although to my knowledge it will be a first. Guess the only way to to eliminate the ignition is to borrow a temporary replacement and try it. That is the only option I can think of to suggest. Good luck--
Foggy
Foggy
Think i may go this route...anyone tried these?
http://m.ebay.com/itm/190590733267?nav=WATCHING_ACTIVE
http://m.ebay.com/itm/190590733267?nav=WATCHING_ACTIVE
Thought of something else in the maybe category. My outboards (2 cycle) all have internal gas filters located in the fuel tank. I have no clue if the Stihl uses an internal filter or not but if they do.......I would jump on that for sure. In my ouboards, the filter is attached to a rubber like hose that floats around in the fuel tank. I think if you can shake the saw without fuel, you should be able to hear it rattle.
I would also try squirting some carburetor cleaner or starting fluid into the carb while the saw is running to see if it normalizes for a couple of seconds.
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