ANOTHER Quadrajet problem.....

[wilkboater]

I'm working on an '88 Bayliner Capri, 102 hours, 5.0 GM OMC cobra drive. Had the carb rebuilt last year, ran perfectly when it was winterized in September. It started after about 10 seconds of cranking this spring, but it won't wind out completely when the secondaries open. It idles good, is very responsive, everything is good, until you get into the secondaries. Everything is cleaned and lubed, all linkages are free, fuel filter is clean. The air shutters on top open slowly(but move freely when it isn't running), and fuel is present; I removed the top of the carb and blew carb cleaner through the secondary circuit, nothing was stopped up(BTW carb cleaner really burns your eyes). I'm running out of ideas.........can anyone help?

Thanks,
Jeff

 

[robjen1019]

Re: ANOTHER Quadrajet problem.....

There is an adjustment for the spring on the secondaries. The spring might be set to tight. do a search on google for adjust qjet secondary. Should come up with some pictures.
If you decide to adjust it, be careful with the set screw. Take note where the spring is initially set. Once that set screw is loosened, it will uncoil.
What I do is make sure I have a screwdriver in the adjustment screw before I loosen the set screw.
sounds like yours is too tight. Once it gets to loose, the engine will bog when opening the secondaries on acceleration.

 

[Menace2Authority]

Re: ANOTHER Quadrajet problem.....

Q-jets are cheap at scrap yards. Find an old trans-am or camaro with a HO 305. 100 bucks might save u a lot of headaches.

Good luck

Rob

 

[wilkboater]

Re: ANOTHER Quadrajet problem.....

Yeah, I've read up on the spring adj. procedure. If I understand it correctly, that controls when they open, and how quickly; am I correct? My problem isn't when they open, or how quickly, it's that they open, and the engine never really winds much farther. It goes into sort of a "sustained bog" and doesn't get any better. Will the spring cause that?

What baffles me here is that it was put away running perfect, no one has messed with it, and now it doesn't run right. Welcome to boating.

Thanks,
Jeff

 

[lonemust]

Re: ANOTHER Quadrajet problem.....

You said it doesn't open all the way. Yes if the spring is to tight it won't open allthe way. Vanish or "goop" can buildup on the pivot points during the winter and that can cause your problem too. When the air flap opens it lifts 2 needle valves to allow fuel to enter the back two barrels on the carb. If the flap doesn't open all the way the engine will not rev right do to lack of fuel. carefully pull the screw in the middle of the flap and remove the lever(with the 2 metering rodshooked to it) and clean the metering rod with solvent real good, if they have the slightest buildup on them they wont let gas flow right either. And while the metering rods are soaking spray the flap shaft really really good with a high quality solvent. I prefer chemtool b-12. It contains acetone which works forremoving the gum and gunk the coats the shaft over the winter. This has always seemed to be a problem with every Q-jet I have ever rebuilt on a car/truck carb that would see alot of set time.

 

[Lennyd123]

Re: ANOTHER Quadrajet problem.....

Not sure if this is your problem, but it seems the new fuels are really causing problems for many as they seem to be cleaning out years worth of junk that has accumulated in the tanks, and sending all kinds of water through the system.

I am battling this myself and have been dumping the spin on filter after every run and am amazed at what I am finding in the filter.

I gave up on the old rebuilt carb, and want to try and keep the new one from getting junked up etc so I am hoping that I can stay ahead of the crap getting past a clogged up filter.

Take a look at what your filter has been trapping, and if its not pretty check it its getting into your carb.

 

[cr2k]

Re: ANOTHER Quadrajet problem.....

Rebuilding the carb shouldn't effect the secondary spring setting. If it ran before there is something else wrong. I would suspect a vacuum leak.

MENACE2AUTHORITY....NEVER EVER EVER Put an automotive carburetor on a marine engine. Besides being highly illegal it is one of the best ways to blow your boat up and kill people. The next would be a car distributer, starter, alternator or fuel pump. ALL DIFFERENT from their automotive counterparts.

Just as a Marine engine LOOKS like a car engine, a Marine carb looks like a car carb, They ARE different.

 

[6meter]

Re: ANOTHER Quadrajet problem.....

Try here.

http://www.lbfun.com/warehouse/tech_...ng Paper.pdf