Q-jet float setting

[boatman37]

hey guys. i have rebuilt several q-jets back in the day but my 1986 merc 260 q-jet (#17080561) tag # MCM 260/270 1347-8292 says to set the float at 1/4" and to measure about 3/16" in from the end of the float. my old float was set closer to 1/2". i just want to make sure i am using the correct setting?

come to think of it, i measured the old one with the new needle and seat so that may have been the difference. so does the 1/4" sound right?

 

[Bt Doctur]

http://www.florida4x4.com/tech/quadrajet/index.php

 

[NHGuy]

For 1985 to 1988 Mercruiser Quadrajets on 350's you measure from the casting surface to toe of float. It's supposed to be 15/64" +/- 1/64. Sounds a lot like a scoshe under 1/4" to me.

 

[boatman37]

thanks guys. i just got back from the boat. put it on but had trouble getting it to start. held the choke flap open and then it started and ran fine after that. same thing as before. sounds to me like it was flooded?

 

[NHGuy]

Yes. it does.
First start after installation isn't normal though. Remember the bowl needs to fill, and if you get the bowl full while pumping the gas it could have flooded due to that. So give it another cold start try before taking it apart.
What happens if you watch the primary venturi's during cranking and after shutdown? Any drips?
How are the needle and seat? You check the seal by turning the carburetor over and applying vacuum to the fuel inlet.
Also check that the float pivot is assembled correctly. Inspect the needle and seat for marks and damage that could flow fuel even when the float is at it's full point,with the needle seated.
If all that is good, maybe do some more checking at some of the carb and hot rodding sites for float levels.
If it still gives you trouble post back, I have a really good quadrajet book and I will go through the troubleshooter for you.

 

[boatman37]

thanks NH. there were no drips or signs of any fuel after shutdown. and i was aware of the float bowl being empty so expected the first startup to be difficult. it fired right back up instantly after the engine was warm and the choke flop fully opened but as you said, i knew i needed to try it cold again so came home and will try again today with a cold engine.

i also pulled my vacuum gauge out of the toolbox last night and will try to get that hooked up to manifold vacuum today to see how that looks and will report back later

 

[boatman37]

update, just got back from the marina. boat fired right up and idled good. i set the idle to ~650 in gear and ~700 in neutral. went out and ran it and seemed fine. putted down the no wake zone about 30 minutes down and back and it ran fine. i think (hope!) the issue is fixed. i think i may have flooded it yesterday trying to get the fuel bowl filled. thanks for the help and i will let you know how tomorrow goes

 

[boatman37]

went out again today. fired right up and ran good. hope the rebuild fixed it