Quadrajet problems

[fendersfender]

Well...i have a carb issue with a quadrajet 4 barrel...carb was rebuilt over the winter (soaked and blown out with air) put the boat in last week, fine tuned idle mixture screws and let sit and idle for a good hour, no problems...went fishing the other day and both engines ran perfect....i troll with port motor (power steering) so starboard engine was shut off....when done fishing, started starboard engine and ran to port, again no problems....when i idled engines down when in port, starboard motor was running rough and died a couple of times on way back to slip.....i went to boat today to check it out and found that starboard carb was pouring fuel into intake...so i took top of carb off to check float and needle seat, everything looked ok, but it still pours fuel into intake when "trying" to run...... i think it has to be float or needle seat allowing fuel bowl to overfill....any tips or ideas will be appreciated. thanks

 

[Don S]

Re: Quadrajet problems

What are we working on?????

Any gas in that clear hose between the fuel pump and the carb? If there is, you have a bad fuel pump that is dumping gas into the carb.

 

[Maclin]

Re: Quadrajet problems

There could be another problem lurking within the carb(s). Quadrajets have well plugs in the bottom of the fuel bowl, these are originally just pressed in and can begin to lose their seal and leak fuel from the bowl thru the throttle plate and directly into the intake manifold plenum. A Google search for "quadrajet well plugs" will return a good many listings on this subject. Other carbs have problems with these also, not unique to QJ's.

The symptoms are overnite drain of the fuel bowl, hard re-starting and rough idling and rough running due to an over-rich condition, after turning the engine off you can sometimes hear fuel dripping into the intake and sizzling as it hits the heated plenum floor but can't necessarily see where it is coming from.

 

[fendersfender]

Re: Quadrajet problems

Sorry Don,
Its a '85 searay w/ twin 3.8L v6 OMC's....... Come to find out, one of the new brass floats was leaking and sank on me ..... put in another float, set float level and fine tuned carb and it runs EXCELLENT.... the notorious leaking well plugs were also sealed up during the rebuilds....thanks boys!!!

 

[Maclin]

Re: Quadrajet problems

Glad you found it

 

[mthieme]

Re: Quadrajet problems

FWIW and if it helps anyone else....
I rebuilt a carb this winter and it sat around the woodshop until last month. It wouldn't run after installation. Dust had clogged up the idle circuit.
Next time I'll store it in a zip lock bag.