SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: Steel Gromet on April 15, 2011, 05:02:32 PM

Title: Carb issues, i think!
Post by: Steel Gromet on April 15, 2011, 05:02:32 PM: Took the boat out to blow all the cobwebs out. Would inly rev up about 3900 rpm's. Ususally runs up to 5000 or so. It appeared to be starving of fuel. Run a Holley 4150(?) and just replaced the accelerator pump gasket. It has a fuel regulator w/ a guage. Guage reads about 6psi. Doesnt seem the secondary's are opening up and runs sluggish. Any help would be appreciated. Thanks! :banghead:
Title: Re: Carb issues, i think!
Post by: obnoxious001 on April 15, 2011, 05:14:24 PM: Quote from: Steel Gromet on April 15, 2011, 05:02:32 PM
Took the boat out to blow all the cobwebs out. Would inly rev up about 3900 rpm's. Ususally runs up to 5000 or so. It appeared to be starving of fuel. Run a Holley 4150(?) and just replaced the accelerator pump gasket. It has a fuel regulator w/ a guage. Guage reads about 6psi. Doesnt seem the secondary's are opening up and runs sluggish. Any help would be appreciated. Thanks! :banghead:

Vacuum secondary or double pump?

Have you checked to see if there is fuel in bolt bowls, up to the sight plug? Might be a stuck needle and seat if it's been sitting. You didn't open it up while you had it off to replace the accelerator pump diaphram?
Title: Re: Carb issues, i think!
Post by: Steel Gromet on April 16, 2011, 08:57:55 AM: It's a vacuum secondary and didnt open up the carb except to replace the accelerator pump gasket. Prob been siiting for 6 months or so.The gasket can only go on one way right! Nothing else has been messed with including the timing. Thanks for the reply ob001!
Title: Re: Carb issues, i think!
Post by: obnoxious001 on April 16, 2011, 12:57:08 PM: Quote from: Steel Gromet on April 16, 2011, 08:57:55 AM
It's a vacuum secondary and didnt open up the carb except to replace the accelerator pump gasket. Prob been siiting for 6 months or so.The gasket can only go on one way right! Nothing else has been messed with including the timing. Thanks for the reply ob001!

The accelerator pump "gasket" is actually the entire accelerator pump diaphragm, correct?

As I said, first thing is to check and see if both bowls are filling with fuel.

Did you try moving the secondary butterflies by hand? It's also possible the vacuum diaphragm needs replacing.

Maybe just time to pull the carb apart, check it all out and put a kit in it.
Title: Re: Carb issues, i think!
Post by: Steel Gromet on April 16, 2011, 05:53:42 PM: I will check the bowls and if there is fuel I will go through it and see what happens. Thanks again for the helpful info!! :beer:
Title: Re: Carb issues, i think!
Post by: obnoxious001 on April 16, 2011, 11:59:42 PM: Quote from: Steel Gromet on April 16, 2011, 05:53:42 PM
I will check the bowls and if there is fuel I will go through it and see what happens. Thanks again for the helpful info!! :beer:

What I was saying is that if the gauge shows fuel pressure, but the sight plug in the bowl does not, then you have a problem with a needle and seat.
Title: Re: Carb issues, i think!
Post by: SS-201 on April 17, 2011, 01:56:46 AM: Sound like you are not getting into the secondaries. Be sure the vacumn diaphram is moving and not stuck from sitting. Check the spring, if yoo don't already have put the lightest spring in.
Title: Re: Carb issues, i think!
Post by: Steel Gromet on April 18, 2011, 08:29:52 AM: No, i'm definetly not getting into the secondaries. There is fuel to the guage, pulled the sight plug and appeared to be dry. Going to pull it apart and check the needle and seat first!