582 engine won't get to top RPM. Any suggestions?

[jjsound]

Hello,

This is my first post here. Sorry for the length. Thank you for the knowledge I have gained on other subjects. Now I'm a bit stumped.

I have a red 582, all original w/ BS 16hp horizontally opposed engine.

Problem: Won't go above about 1200 RPM even if I override the governer. Slight surging at idle. Full throttle speed is about 1200 and unsteady. Starts almost normally. Takes a bit more effort to start running. I think the exhaust smells more of hydrocarbons than usual.

Here is what I have done.
1- Removed air filter assembly. Confirmed sufficient fuel delivery through fuel line to carb.
2- Completely rebuilt the carb. I have a serious ultrasonic cleaner with proper chemical specifically for cleaning carbs. After COMPLETE disassembly, I checked all passage ways and installed factory rebuild kit. I have about 20 carb rebuilds to my experience. Note: Engine ran the same (bad) before the rebuild as after the rebuild.
3- Confirmed visually enough spray fuel was going down throat while running WOT.
4- Checked for too rich condition by closing the gas tank petcock while at full throttle. Did not experience increase in speed just before fuel exhaustion as a too-rich condition would indicate.
5- Same test as 4 but using pliers across fuel line in case petcock was not really shutting off the fuel.
6- Engine at idle, sprayed carb cleaner at every joint and gasket area I could get to. No change.
7- Pulled plugs. No fouling found. Carefully cleaned plugs, Checked gap visually. Cranked engine, compared spark between the two plugs. Seemed lively enough and equal between them.
8- Compression check using an old Sears compression gauge was 95/97 PSI.
9- One side of engine is running SLIGHTLY hotter than other. Touching spark plug base while running, one side I can hold my finger for about 4 seconds before too hot to touch, other I have about 2 seconds before too hot. I guess about 15 degrees difference.

Six or seven years ago I converted this ignition from points to electronic ignition using factory kit. It ran flawlessly until this prob occurred. I suspect ignition timing problems. Maybe something changed about the ignition module.

I would like to know from anyone, what else I may have missed? I am not god's gift to machines and still have a lot to learn.

Thank you. John
North NJ

[Matt G.]

Did you get the governor linkage and spring reassembled correctly? That engine has the dumbest, most overly complex throttle/governor linkage I have ever seen, and it's pretty hard to put together right without the service manual unless you've done it many times.

[jjsound]

Matt,

Even if I did get the governor assembled incorrect, when I override it by pressing directly on the throttle lever (low on the carb near the intake manifold), the RPMs are limited.

But I am pretty sure the governor was reassembled correctly. Thank you for bringing that to my attention.

John

[jjsound]

I installed new spark plugs and at the same time I noticed the ignition ground wire coming out from under the shroud in a place that might be pinching that wire. I moved the wire to the correct exit hole.

Started it up and it ran fine. Full power now.

So, it was either the plugs or the wire's insulation was wearing away and the copper inside was touching against the sharp edge of the shroud. The engine vibration made it alternate between a short and an open. More RPM = more vibration. More vibration = more shorting and thus limiting the RPM...I guess.

Thought you would like to know what I found.

Thanks,
John

[Matt G.]

That's pretty interesting. That is about the last thing I would have thought to check.