Rochester Carburator

[gldavison]

Hi again-
I finally have the tilt under control and fuel to my carb but I think there is still a problem with the carb.
I have not got something right in my adjusting I am figuring or my float is stuck....This is a 1976 Mercruiser 888 with a Rochester Two barrel carb. I just rebuilt the carb as it sat for 10 years idle.

When cranking I get nothing till I open throttle wide open then the cranking seems to speed up like it is going to fire and get going but never does. After a minute or two of this wishfullness I check the carb and in the body it is pretty full of fuel- this is not suppose to be is it? When my wife cranks on the starter and I watch at the carb fuel is even coming out the top of the air horn.

Two things I was not able to replace when rebuilding were the "guide pump discharge" and ball/spring as I was unable to remove the old ones.

Any advice please. I am getting so close to getting my project running please help!
Thanks,
Greg

 

[wire2]

Re: Rochester Carburetor

Re: Rochester Carburetor

The starter will speed up a bit with throttle open, now the engine isn't working like a vacuum pump.

No, there shouldn't be fuel standing in the carb, it should be atomized and drawn into the manifold.

I'm not clear on what "guide pump discharge" and ball/spring" you're talking about, but maybe get someone to see if they can re & re those parts.

It *might* be as simple as a stuck float valve, but I'd be inclined to let a reputable shop open it and give it a thorough going over.
Or, if that's going to run into big $, look at a new Marine carb from Jeg's or NAPA.

 

[Silvertip]

Re: Rochester Carburator

I've been retired a number of years and it's been a good long while since I was inside one of those but I used to be able to rebuild them in my sleep. If fuel is squirting out the air horn, you failed to install a check ball. Now here's where I get fuzzy, I believe that check ball resides in the bottom of the accelerator pump chamber. How do I know this happens? Many moons ago my brother in law was going to be a good guy and rebuild the carb on my father-in-laws '66 Olds. Got it together and yup -- fuel squirted out the top. When I arrived on the scene I suggested that was the problem but my bro-in-law (who is always right) got ugly sarcastic and said he didn't lose the ball. I toured the work bench and presented him with the ball that had rolled into a crack in the wooden bench.

 

[gldavison]

Re: Rochester Carburator

Thanks I am trying everything you guys are advising.

Greg

 

[rodbolt]

Re: Rochester Carburator

all 2bbl rochesters had an accelerator pump discharge check ball and spring. the guide is the metal cross piece under the venturi cluster. pry the old one out and install the new ones at reassembly. some rochesters had a pump inlet check ball and screen.
the pump inlet just aided in keeping the pump well full to make the fuel go into the accelerator passages and not back into the fuel bowl.
your issues sounds like a bad needle,needle seat bad float or improper float settings.

 

[gldavison]

Re: Rochester Carburator

I think I have it undercontrol thanks to you guys. I was missing the ball in the accelerator pump for one and I think I had the float out of adjustment. I fixed both and no more gas out the top of the carb. Thank you to all.

I still can not get the boat going.

Greg