Generator Governor Issues

[Steve Kraus]

This is a no-name generator driven by an 8 HP Briggs.

It's having speed fluctuations and I'm trying to figure out why. It seems like the governor itself is creating them.

In this video it's running no-load and you can see the speed variations. Sometimes it's worse than this. In the video I reach in and hold the throttle and the variations cease.

The governor, of course, does not "know" the reason the speed has changed, whether it's due to a load change or some other condition; it ups the throttle when the speed drops and reduces it when the speed increases.

In this case there is no load. If the speed variations were due to, say, the carb putting out an inconsistent mixture or some mechanical issue in the engine I think the variations would be worse or at least unchanged with a fixed throttle position. But here a fixed throttle = fixed engine speed. Which leads me to believe the variations are being caused by the governor itself.

On this engine I think the actual governor is a flyweight thing inside the engine. There is a shaft emerging with a lever on it which is linked to the throttle valve.

What is my next step here? Some people have said that the governor spring can be very critical so I guess I'll get a new one to see if that cures it.

Anything else I should be looking at?

[Pat]

It is called hunting. Usually the governor is not at fault. Can be caused by a lean fuel mixture. I would probably clean out the carburetor first.

[LdB]

I had the same problem with a B&S 16HP. I was advised to change the oil in the engine. I did and the speed stabilized. I don't know why it worked but it worked.

LdB

[dpb]

Or an air leak is another common culprit.

Can be worn carb bowl around the throttle shaft, loose carb to block, etc., etc., ...

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[A. Baum]

Appears it's starving for fuel. Mine will do the same thing right before it runs out of gas. Pull the carb bowel and clean the banjo bolt if it has one. That's the fuel pickup. Or/and clean/replace the needle valve and seat.

[Jim Yanik]

"Pat" wrote in news:8badnawY8I4tmH3RnZ2dnUVZ [e-mail]:

could be water in the gas,too,or the motor doesn't like E10.

[hrhofmann]

How does it run under a real load, like a bunch of light bulbs or a motor? THat is what really matters.

[LSMFT]

Could be a normal 'no load' condition. Put a load on it and see if it levels out.

[dpb]

dpb wrote: ...

That would be "body", not "bowl", sorry...

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[Steve Kraus]

About the same. I could post another video I shot with it running a 1200W steam iron as the load and it's very similar.

[Ralph Mowery]

I have a 5 kw generator and it was speeding up and down with out a load. Put around 500 to 1000 watts of load on it and it smoothed out. I drained all the gas one year and put in fresh gas and it smoothed out a bunch from what it was running without a load. Maybe some water or just old gas was causing some of the problems.

[Steve Kraus]

Guess I'll order a carb kit. Again. I grew up with Tecumseh and this is my only Briggs experience. I hope for their sake my experience is atypical because it's been fairly annoying, primarily the carb.

[ransley]

You showed a meter registering HZ I believe, and it seemed to hold

60hz fairly well meaning its holding rpm fairly well. 3600 rpm is 60 hz. What happens when you fully load it to its maximum which should be about 3000w, with an 8hp motor. What you show is it is bad idling, mine does that idling at 3600 no load but is fine loaded with 2-4000 w. I would clean and tighten everything first and test it more.

[dpb]

Well, the problem isn't unique to B&S; I've Tecumseh's that suffer the same fate. But, first determine if there's your problem. You can determine if there are air leaks by the spray solvent test, verify there aren't any leaking gaskets, loose connections, etc. Parts w/o knowing they're the right parts won't necessarily help (and if it were the throttle shaft problem, there's nothing in the kit that'll help, anyway).

How old is the genset, what kind of run time?

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[jamesgangnc]

Change the gas and clean the carb. Generators sit too much.

[Steve Kraus]

Yeah, I think I will try a new spring.

[Steve Kraus]

I do see a bit of gas seepage around where the carb bowl and top come together. That's actually my main complaint about the carb and the reason I bought a kit before. I've polished the mating surfaces, tried it with and without Permatex. Sometimes it's better sometimes not. Right now, if I turn on the gas flow and run it after a time I will see a tiny bit of gas on the outside of the bowl. I have no issues with rest of the Briggs engine but that carb...ugh.

1992. Maybe 100 hours. A few good runs during blackouts and a lot of half hour test runs.

I try to test run it periodically and turn off the gas flow to let it run out of gas. I don't know if that drains the carb bowl or not. I change out the gas if it's been in the tank a long time or just let it run out of the tank. I sometimes use Sta-bil but not all the time; sometimes it's better just to replace the gas and use it elsewhere.

[jamesgangnc]

I let mine run the bowl dry. I put stabil in the gas and I just keep a little gas in it so I can test run it every couple months. If I have no call to use it for a year or so I drain all the gas in it and put in a little fresh gas in for the next test run.

I know that fuel exposed paper gaskets can shrink when they dry. For the most part they should swell back up when exposed to gas again. Occasionally something might need tightening if something still leaks. Those small carbs only have a few gaskets on them.

Depending on how and where it is stored it might be worth while to use some of the marine engine store spray on it. It's basically a spay oil used to store marine engines over the winter. You spray it down the carb until you manage to stall the engine. Or shut it down while it's flooded with oil if you can't quite stall it.

I spray ether down carbs to get things to start but never down the spark plug hole. That really is a bad idea as the cylinder below the rings is lubricated with spashed oil. Too much ether will wash by the rings and leave the cylinder walls dry. It shoudl reoil pretty quickly but there still is no reason to do it.