merc 260 q-jet fuel drips from boosters

[indy440]

I've had this boat since 2014 and it runs pretty good. Its a Mercruiser 5.7 with a q-jet carb. Last night i just happened to look down inside the carb while it was idling on the hose and noticed there was fuel dripping from the boosters. It was running perfectly. Idling around 700rpm. I didnt expect to see fuel coming from the booster. Im guessing something must be wrong? Once I shut the engine off no more fuel drips.

Its a 1990 Wellcraft 226

 

[Bt Doctur]

high float level leaking needle/seat

 

[kenny nunez]

One other thing that causes the drip is a partially blocked air bleed tube near the booster. Sometimes a small piece of wire pushed down through the tube and some carburetor spray might work. Also removing the idle air screws and blowing cleaner and air works. They are not hard to rebuild and kits are cheap so you may have to go through it.

 

[indy440]

Unfortunately we're leaving for vacation next week and I will have almost no time to look at it again before we go. I just wont let it idle so hopefully it doesn't dilute the oil with raw fuel. Definitely not ideal. For all I know it could have been doing this for years.

I guess another option would be to order a refurb carb and get overnight shipping. I could swap the carb there even if it were already in the water

 

[Scott Danforth]

you have time to take care of it this afternoon

 

[Lou C]

I had this on mine (nozzle drip) and it was just as Kenny said. I soaked it well and used a real compressor not canned air to blow out the idle air tubes. You can run it that way though, it won't really hurt anything. If you have an original un-molested Marine Q-Jet DO NOT exchange it for a rebuilt unit, those can be Franken carbs that never work right. Take the time to learn how to take it apart (not that hard, the main tricks are the accel pump roll pin and the choke linkage) then the air horn comes off, when re-assembling the trick it to get the primary metering rods in right and the gasket for the air horn. Note the position of the little hook that attaches to the needle valve, not supposed to be in one of those holes...
Everything else is easy.

 

[indy440]

you have time to take care of it this afternoon

I wish I had the time. Too busy with kids playing sports and one that races motocross. I've only put 8 hours on the boat in 2 years...

 

[indy440]

I had this on mine (nozzle drip) and it was just as Kenny said. I soaked it well and used a real compressor not canned air to blow out the idle air tubes. You can run it that way though, it won't really hurt anything. If you have an original un-molested Marine Q-Jet DO NOT exchange it for a rebuilt unit, those can be Franken carbs that never work right. Take the time to learn how to take it apart (not that hard, the main tricks are the accel pump roll pin and the choke linkage) then the air horn comes off, when re-assembling the trick it to get the primary metering rods in right and the gasket for the air horn. Note the position of the little hook that attaches to the needle valve, not supposed to be in one of those holes...
Everything else is easy.

I think the plan is to try and poke some wire thru those air tubes and if that doesnt help I'll just run it as-is. We dont idle much anyway. Honestly it could have been doing this for years and I've never looked. Heck it could have been doing it since we repowered in 2015.

In the meantime I'll order a rebuild kit and maybe at some point this fall I'll take my time and rebuild it. Its likely that this trip will be the only time the boat gets wet this year.

I dont think this is a sunken float, or large partial stuck in the seat, issue because i can run it on the hose at 2000+ rpm for considerable time and it never starts pushing fuel out of the vent.

 

[kenny nunez]

You do not have to take the carburetor apart to push wire down through the bleed tubes and removing and blowing out the idle mixture screws. Usually a shipping tag wire is small enough to go through the tubes. If you want to remove the screws first screw them in and count the turns so that you will have a reference where to re set them at. Q jets usually like 3 turns out from seated.
Most auto stores will have the flexible tool that fits the head of the screws and makes it easy to adjust or remove them.

 

[indy440]

Got a chance saturday morning to look at it again and actually put the boat in the water for a few minutes, it seems to have healed itself up. No more drips at all.

 

[tank1949]

I wish I had the time. Too busy with kids playing sports and one that races motocross. I've only put 8 hours on the boat in 2 years...

So gas sits in tanks/lines/ carb bowl and breaks down over time and creates crap and then gets into small places inside carb... Perhaps after total cleaning of carb and maybe a rebuild, there is a better method of winterizing? Your problem happens all the time. Trust me!