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Tecumseh OH-160 ignition problems, HELP!


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#1 tweidman OFFLINE  

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Posted August 18, 2011 - 11:22 AM

I have an OH-160 that has had the SSI module replaced with a GM ignition with a Bosch pick up. The flywheel has had the long pin on the left removed. This was all done by the PO.
It starts and runs, at idle and low rpm it's great, but as soon as you throttle it up, it starts misfiring and too much throttle will make it quit.
I assume it's a timing issue, but I'm not sure what to do to fix it?
The missing long pin is for starting (correct?), so does it matter that it's missing?
Can too much or too little air gap cause this sort of thing?

What to do....:confuse:

#2 mikebramel OFFLINE  

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Posted August 18, 2011 - 09:04 PM

Sounds like the missing pin is for higher rpm

do you have a timing light to see if it adjusts

#3 tweidman OFFLINE  

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Posted August 18, 2011 - 10:18 PM

I have a timing light, I have never used it on a single cylinder engine. See if what adjust?

I ordered replacement pins today. I guess I can see if that helps?

#4 MH81 ONLINE  

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Posted August 18, 2011 - 10:28 PM

On my HH120, the taller pin is on the left. That should be your start pin, the shorter one is for run. I'm wondering if the pickup is too close to the pin and as RPMs increase, the flux field is advancing timing too much... Or the pickup isn't doing what it should because it's too close to the large steel flywheel and trying to see that itty bitty pin?

#5 mikebramel OFFLINE  

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Posted August 20, 2011 - 04:13 PM

Is the gap .010

#6 bread320i OFFLINE  

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Posted August 20, 2011 - 04:34 PM

This problem could be a improperly adjusted carburetor.

#7 DH1 OFFLINE  

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Posted August 20, 2011 - 05:15 PM

Todd, you probably all ready done this but have you hooked up an inductive timing light to see if you are loosing spark as RPMs go up?

Are you sure it's not the spark plug? Reason I say is 2 or 3 times in the past I had the plug give those symptoms, I went nuts trying to figure it out, pulled the engine apart looking for something wrong and found the spark plug bad, when I replaced it no problem.

IMO the engine will run with 1 pin in. I think the tall pin is on the left for starting and the short one on the right advances the timing above 800 or so rpm.
If you only have the pin on the right in, that's the one for running it advances the timing and it should run fine.
The tall pin on the left makes it easier to start the engine, less kick back.
As Mikes says tall pins air gap should be .010, too tight it might touch and ground the pickup coil out???

Picture from manual for HH100 or 120s
HH 002.jpg

Attached Thumbnails

  • HH 001.jpg

Edited by DH1, August 20, 2011 - 05:23 PM.
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  • mikebramel said thank you




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