Engine rev after carb overhaul continued...with pics!

Ok. Here is the situation. I really appreciate all the help as I have no one around me to help out. I took the carb off of my 300u yesterday. Replaced the gaskets and float valve to stop a leak. put the carb back on. leak stopped but the engine revs too high. My tach is broken. So I don't know how high. I checked today to make sure that I properly attached the governor control to the carb. I was able to peek in at the throttle plate as my wife (lol) moved the throttle control. with the throttle closed, the plate closed, with the throttle open, the plate opened. All looked good. I put it all back together and... same thing. There are 2 possibilities in my mind. I will state them and you guys and gals can suggest whatever else.

1-somehow the governor is throwing the throttle open when it shouldn't. Not all the way... because I can rev the engine a little higher manually with the throttle control. (i do not know how I could have screwed this up by taking the carb off.)

2- When I took the carb apart there is one piece that I am unsure of its function. On the attached photo note the post sticking up toward the rear of the carb. This post inserts into a hole on the top of the carb in which there was a rubber.. something... washer... gasket... who knows. This piece is all but destroyed. The carb rebuild kit I got does not have this piece. What is this piece? Could it be causing my problems?

If not, is there a way I can figure out how I screwed my governor?

Pull the cover off the side of the gov & see if the thrust bearing fell apart.

That "post" sticking up is the idle jet and there is no rubber part where it goes into upper carb body. I would look at the gov also.

If you are talking about the "post" sticking up inside of the round area, that "post" is the main metering stem, and yes, there is supposed to be a hard, fiber gasket under it. If that gasket is missing, you would experience some engine running issues, maybe too lean, or maybe too rich, but I don't think it would cause the problems you are describing.

I really think you have missed getting that tab into the slot. The throttle shaft in the carburetor fits into a recessed area on the governor shaft, so even if you missed getting the tab into the slot, there would still be some movement of the throttle plate when the throttle handle is pulled back and pushed forward.

I think you nailed it, but let's hope he opens up that governor case before he blows up that engine.

I'm with Rusty, when you at the inside of the shaft coming from the governor to the carb there is a small tab that noticibly sticks out. On the carburetor, that tab **HAS TO** line up in its slot properly. It is a pain in the A$$ sometimes, but a little patience pays off!!

I have been in the governor. Bearing is intact. OK I hear you on lining up the tab and the recess in the carb. I really thought I had it. I will try again. BUT lets assume I am getting it in the slot. Any other ideas?

And the post I am referring to is not the one in the center but the one towards the rear. There was a rubber ...something.. inside the hole that it matched up to. I removed it.... and now it is trashed.

I will try again to align the governor shaft. Any other ideas?

(quoted from post at 11:01:09 08/17/11) I have been in the governor. Bearing is intact. OK I hear you on lining up the tab and the recess in the carb. I really thought I had it. I will try again. BUT lets assume I am getting it in the slot. Any other ideas?

And the post I am referring to is not the one in the center but the one towards the rear. There was a rubber ...something.. inside the hole that it matched up to. I removed it.... and now it is trashed.

I will try again to align the governor shaft. Any other ideas?

Click to expand...

There is not supposed to be anything in the hole that the idle metering jet fits into. If there was, it was some kind of foreign material crud, sludge, etc. That hole is to be clean.

If the throttle plate was taken out of the shaft, it might be improperly centered and stuck part way open. To fix, unscrew the idle speed stop, then loosen the screws holding the throttle plate, move the throttle closed against the housing, and retighten the screws. The most likely is the tab and slot issue already mentioned!! it is a pain. Jim

I am thinking that I got the tab in the notch as it should be. Because if I got the tab below the notch then I would have seen the throttle plate open easily but had a hard time closing it. If I got the tab above the notch then I would be able to close the throttle plate but it really wouldn"t open. When I was able to peek inside and work the control lever, the throttle plate opened and closed completely each time the lever was moved up and down.

Is there anything else this could be?

I should say that I have NO experience whatsoever. I could have done 100 things wrong. Don"t assume I did anything right. I am a total novice.

For example. I cant for the life of me figure out how the idle screw does anything. All I can see is a tiny pin point that moves slightly in or out inside the top of the carb as I screw it in and out. I have no idea how that affects anything.

OK so....now that you know who you are working with... and assuming I am getting the governor connected right... what else could this be? You guys are my only hope!

Nah, the throttle plate will move even if its not lined up. The gov. isnt going to work "right" without the engine running anyways, so thats really a mute point.Hate to say it, but I agree with everyone else, the tab isnt in the right place.

On your idle screw, are you talking about the idle speed, or idle mixture screw?

i dont have an answer to your question but i would soak that carb in carb cleaner. it looks a little crusty. maybe you have a worn shaft? also are you sure all the jets are adjusted correctly? maybe throttle butterfly got turned the wrong direction or something?

Sean, I have fought a lot of those governor tabs over the years and thought I had the hang of it until last winter. I put the carb back on my M and she wanted to run wide open. I checked that tab and was just sure I had it in the right place and still same problem. I fought this thing taking it on and off several times and finally got it. I was just sure for a while that it had to be something else but in the end it was the tab. I have done quite a few of these and never had as much of a fight as I had with that M last winter. Good luck.

There is one other thing I have done so I know it can be done, if the air horn is upside down it will run wide open. (the throttle plate hits it and it can t close.)