Carburetor Problem

[a1nowell]

'84 JC Tritoon w/MC 470. I have the Rochester 2 Barrel carb. I am experiencing carb flooding. I have cleaned and rebuilt the carb, new needle and seat, gaskets, pump etc. I am still having the problem. I can start the engine and it will run 2-3 minutes just fine no flooding, then it will start to flood. I have checked the float, dry, no leaks. Float is adjusted correctly, no trash in or around the seat & valve.

Any suggestions?

 

[Don S]

Re: Carburetor Problem

Is it flooding from too much fuel, or the choke not opening as it should?
Another possibility is a fuel pump failure and the extra fuel is coming into the carb from the clear hose from the fuel pump.

 

[a1nowell]

Re: Carburetor Problem

Don,
The problem is too much fuel, the choke is open. I do not think it is the fuel pump because I have a spare carb and have put it on and I have no flooding problem. My spare works but is not the correct carb for that engine, it's off a 140 HP engine.

 

[GLENN M]

Re: Carburetor Problem

if that's the case when motor quits does fuel continue to pour down carb.only two things can cause this if fuel pump not leaking, that's float setting or needle and seat ive had brand new needle seats leak,you have to go back and find problem.before i put back together i always try blowing through carb raising and lowering float make sure it shuts fuel off.

 

[a1nowell]

Re: Carburetor Problem

Glenn,
Yes, after the motor dies the gas continues to flow down the carb into the intake manifold.

 

[CobiaXL]

Re: Carburetor Problem

3 things to check that would cause your issues..

1. Float not adjusted correctly or float has hole in it.
2. Needle not seating correctly.<Check the little clip on top of needle>
3. Too much fuel pressure.

 

[Joshua Nichols]

Re: Carburetor Problem

Okay likely needle is leaking.. Pull the carb and make sure it is sealing up.. I know you said the float is okay, but did ya make sure it floats? Some will get a bit of gas in them and it is enough to hold the float down enough to flood the carb... Did you use the gauge to set your float correct? When ya get the carb off blow in it while operating the float and see if it seals

 

[GLENN M]

Re: Carburetor Problem

check also if needle has teflon tip or not,if not sometimes very gently tap needle to set it in seat,had to do that on a lot of gm cars to get them to seat.now iam talking tap it gently if its all metal needle and you can blow through it when closed,rare floats sink it will most likly be a needle seat issue,or float not set right goodluck[3 times a charm]

 

[backyard mechanic]

Re: Carburetor Problem

Along the "check the float" line... Many of the older Rochester 2bbl carbs had a black foam float. With ethanol fuels, they break down. That is going to cause you trouble. Make sure your float is alcohol compatible. Be careful with the metal ones too... they were painted with shellac as a sealer. Remember; alcohol is the reducer and cleaner for shellac.

Good luck!

 

[poorguy]

Re: Carburetor Problem

Is it flooding from too much fuel, or the choke not opening as it should?
Another possibility is a fuel pump failure and the extra fuel is coming into the carb from the clear hose from the fuel pump.

What is the purpose of this clear hose from the fuel pump to the carb? Thanks.

 

[mkast]

Re: Carburetor Problem

Read this.

Weigh the float.

 

[Bt Doctur]

Re: Carburetor Problem

What is the purpose of this clear hose from the fuel pump to the carb?

Called a "telltale" .It lets you know the pump diaphram has ruptured and the fuel that would normally dump out into the bilge now goes up to the carb.

 

[dccordell]

Re: Carburetor Problem

I had this same problem with my 2bbl rochester a little while back. Most of the things I checked was the float (check it, set it, check it 2x again) and make sure if your carb had the little ball under the throttle pump, it needs to go back in during the rebuild. Make sure you replaced the needle AND seat that came in the kit... not just one or the other (you said you replaced both, but just checking).

Somebody had told me to hold the carb upside down with the bowl removed (with the float in closed position) and blow into the fuel inlet and listen if you hear any air slipping through the needle. Some other people questioned this test, but it seems reasonable, just to test if the needle is seating.

Mine was flooding almost immediately, so I likely had a different problem. Good luck..