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Onan P218G Carb Linkage

6040 Views 5 Replies 5 Participants Last post by  chuckv
I've resealed my intake manifold and put everything back together and started it up but it revs way up. The only way I can control it is to push the governor arm towards the front or the tractor. That's the only way I can control the revs.

When I reassembled the linkage I couldn't remember where or how the front was hooked up to the carb. Here a picture of the linkage:

I remember where it was in the back by the governor shaft but not up front. If I hook it up as what I think is correct the spring and linkage open the butterfly wide open. Can anyone give me a suggestion? It doesn't make sense to me that the butterfly would be positioned furtherest away from the idle adj screw,

Thanks in advance for any help.
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My Onan engine manual only describes "hunting" in terms of a poorly adjusted or worn governor linkage as seen here:
Check the governor arm, linkage, throttle shaft, and
lever for binding condition or excessive slack and wear
at connecting points. A binding condition at any point
will cause the governor to act slowly and regulation will
be poor. Excessive looseness may cause a hunting
condition and regulation could be erratic. Work the arm
back and forth several times by hand while the engine is
idling to check for above conditions.

This is by no means "official" but my understanding of surging as used on this site is the temporary over-speed of the engine at idle when the fuel to air mix is too lean forcing the governor to open the throttle plate -- which speeds up the engine enough that the throttle is then closed by the governor and the cycle repeats. This mix error can be from a fresh air leak below the throttle plate (worn throttle shaft bushings, failed manifold gasket, or more commonly a leak in the two part intake manifold from a failing seal...) or from a plugged low speed jet. Either can produce a lean mix at idle but seem nearly normal at WOT governed working RPM. JMHO

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