Engine Engine surges(revs up & down)............

Surging comes from a fuel issue...... Either your filter is stopped up and you are not getting enough supply for the demand or you idle port in the carb is dirty or the whole carb is dirty and needs a good cleaning .....

I just helped a guy on here a couple days ago with his running rough Kohler 20 HP engine... He said he cleaned the carb well , but I thought differently from my point of view as a mechanic.....

Sure enough he went out and bought a reasonably priced Ultra Sonic cleaner and tore the carb down again and gave it a great cleaning....

He put it back on and is up and running again smoothly.........

Those carbs are easy to clean.......... I'll find a video link for you to watch.....

Hold Tight Mon Ami .........
 
Boudreaux In Eunice La. said:
Surging comes from a fuel issue...... Either your filter is stopped up and you are not getting enough supply for the demand or you idle port in the carb is dirty or the whole carb is dirty and needs a good cleaning .....
QUOTE]


Isn't most RPM surging from a mis-adjusted governor???

Perhaps a posted You tube video of the issue would help us...
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SRTsFZ6 said:
Boudreaux In Eunice La. said:
Surging comes from a fuel issue...... Either your filter is stopped up and you are not getting enough supply for the demand or you idle port in the carb is dirty or the whole carb is dirty and needs a good cleaning .....
QUOTE]


Isn't most RPM surging from a mis-adjusted governor???

Perhaps a posted You tube video of the issue would help us...
Click to expand...

Almost all surging issues are fuel/carb related. I have only seen governor sensitivity issue problem less than half a dozen times in over 20 years.
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SRTsFZ6 said:
ILENGINE said:
So the governor, moving back and forth is due to carb fuel flow (or lack of) compensating for it?
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correct. The engine when not under load runs on the idle circuit of the carb, but if that system is partially or fully clogged, the engine can't get enough fuel to run at that rpm, the rpm's start dropping and the governor spring opens the throttle which causes the engine to get fuel from the high speed jet. And then the engine speeds back up closing the throttle, which repeats because of not enough fuel on the idle circuit in the carb. So if you partially close the choke you richen the fuel and the surging stops. Also if you put a load on the engine the engine opens the throttle butterfly to compensate for the lose of rpm, and then is running on the high speed jet which in most cases will also stop the surging.
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Right on target there. I do have a couple smaller engines that surge or hunt with no load, but engage the drive and they smooth out and run perfect. I can lean them out some and they smooth out but when the load hits they don't pick up like they should. These simple carbs are pretty limited in what they can do I guess.
 
ILENGINE said:
SRTsFZ6 said:
correct. The engine when not under load runs on the idle circuit of the carb, but if that system is partially or fully clogged, the engine can't get enough fuel to run at that rpm, the rpm's start dropping and the governor spring opens the throttle which causes the engine to get fuel from the high speed jet. And then the engine speeds back up closing the throttle, which repeats because of not enough fuel on the idle circuit in the carb. So if you partially close the choke you richen the fuel and the surging stops. Also if you put a load on the engine the engine opens the throttle butterfly to compensate for the lose of rpm, and then is running on the high speed jet which in most cases will also stop the surging.
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Interesting re the choke. Gotta try that next time I come across a surging governor.

Tks..
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