Amateur rochester 2GC carb rebuilt, leaking shaft

[artificialreef]

Hello again friends. Progressing well on my twin 470 mercruiser resurrection. Put one carb i rebuilt back on, fired her up and am trying to set the dwell. I am using an external tank untill i get them both running well and every time i start it i pour some fuel down the line to get it primed.
Well today i had some fuel left in the cup and just poured it in the carb instead of back into the tank and noticed fuel leaking out of the throttle plate shaft onto the manny. Yikes! Looks like an explosion waiting to happen. I dont believe i soaked the plate in the carb cleaning bucket.
Questions:
1. Are the throttle plate bushings something that gets changed in a carb rebuild. There werent any in the kit?
2.Are they rubber bushings that are easy to put in and easy to get. This is a Rochester 2GC on 1983 mercruiser 470.
3. Do people check for this or just run like this because the carb doesnt usually doesnt get filled up with fuel like i did (just got lazy). Just seems very dangerous.
Almost had to change my username to burnedtothetrailerline since i havent got it to the water to be an artificialreef yet.
Thank you for your knowledge and willingness to share it.

 

[Fishermark]

Re: Amateur rochester 2GC carb rebuilt, leaking shaft

If the throttle shaft is loose and leaking, the bigger problem is usually a vacuum leak and erratic idleing - not a big explosion factor.... unless you pour a bunch of gasoline down the throat.

I don't believe that replacing the bushing is a typical thing - those carbs are simply replaced as they are literally worn out.

 

[artificialreef]

Re: Amateur rochester 2GC carb rebuilt, leaking shaft

Thank you for the reply Fishermark. It idles and runs like a champ. I havent even set the dwell and timing yet. Do you mean i can run it like this if it runs good?

 

[Fishermark]

Re: Amateur rochester 2GC carb rebuilt, leaking shaft

Yes - run it. The shaft is not designed to keep raw fuel from leaking out. It is designed to be tight enough not to cause a vacuum leak.

 

[Silvertip]

Re: Amateur rochester 2GC carb rebuilt, leaking shaft

At idle there is so much vacuum at the shaft no fuel could get out even if you poured it down the carb. At wide open throttle there is so much air passing down the carb throat fuel can't possibly get upstream. Be more concerned about wear in the distributor shaft upper bushing than the carbs. When you set the dwell, watch the meter carefully as you blip the throttle a time or two. Dwell does not (or should not change) with engine rpm. If it does, the distributor shaft is wobbling in the bushing and it's repair time. The reason the dwell changes is because the shaft is opening and closing the points erratically as it rotates.

 

[ziggy]

Re: Amateur rochester 2GC carb rebuilt, leaking shaft

agree with everyone like usual.
i'll add that i've seen throttle shaft wear on an auto carb (i know, boats ain't cars, but this one it may not make a difference). the consequences were the throttle plates literally shaving the metal off the venturi. then you can't set idle mix because of the leak by the throttle plates at the wear in the venturi.

 

[Gary H NC]

Re: Amateur rochester 2GC carb rebuilt, leaking shaft

I agree too,If you can get it to idle ok and the dwell set then run it like it is.
If not a new carb is in order.There are plenty of the 2 GC carbs around.

 

[Alpheus]

Re: Amateur rochester 2GC carb rebuilt, leaking shaft

Yes they make a kit that you can drill out the throttle plate and install new bushings. They are there to prevent vacuum leaks. You will never get your idle set right if its leaking air. This is one of the biggest reasons people throw away a perfectly good carb after they rebuild it and cant get their engines tuned right...

http://www.supercooltools.com/html/ZA-ATS/index.html