SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: Steel Gromet on May 04, 2011, 09:19:54 PM

Title: Carb issues pt. 2/Holley 4160 750 cfm
Post by: Steel Gromet on May 04, 2011, 09:19:54 PM
Well thanks for the replies on my first post!  The advise was right on the money, but didnt have clue what I was doing (kinda).  Removed the carb and took the bowls off.  the prim bowl was wet, but the secondary bowl was dry.  Probably the reason the secondaries were'nt opening up :screwy:   Bought a trick kit and got most of the carb put back together, but there is 2 small cork pieces and not sure where they go??  Any info would be appreciated!  Thanks.  Can post pics if it helps, but just got home from work...
Title: Re: Carb issues pt. 2/Holley 4160 750 cfm
Post by: Nordie on May 04, 2011, 09:45:21 PM
they go around the air bleeds in the primary metering block...those little brass flat head screws on the side of the carb...one on each side
Title: Carb issues pt. 2/Holley 4160 750 cfm
Post by: HomeBlown57 on May 05, 2011, 08:05:51 AM
If the piece is very thin like .030 it could also be a gasket between the vacuum secondary diaphragm housing and the carb body. Sometimes these are made of gasket material and sometimes cork. Pics always help.
Title: Re: Carb issues pt. 2/Holley 4160 750 cfm
Post by: TIMINATOR on May 06, 2011, 09:00:46 AM
Vac. secondary carbs will never fully open the secondaries at jetboat RPMs unless you run an extremely light spring in the diaphram, then you will have a bog on acceleration as they will open too quickly. The additives in the fuel(alcohol or MTBE) will harden the sec. diaphragm in short order too. If you insist on using a vac secondary, plan on replacing the diaphragm every 3 to 6 months. No happy medium here, use a double pumper, you will be much happier. It is hard to overcarburate a jet motor, get an 850 or HP 970, even for a stock motor. The larger primaries allow you to cruise on plane on just the primaries, something you can't do with a smaller carb, especially a Quadrajet!  TIMINATOR
Title: Re: Carb issues pt. 2/Holley 4160 750 cfm
Post by: Steel Gromet on May 06, 2011, 03:11:59 PM
Thanks for the replies.  There are so many gaskets and o-rings, one can easily get confused!  Mounted the carb and so far so good.  It fired right up! I will take it out next week and so how she does.  Timinator put maybe I should ditch my carb and go with a double pumper.  Would it be better on fuel economy and power?  I'm running a BBC.  I tracked down some previous owners, but all they new was it had a big cam.  Took off the valve covers and it had GM performance heads and Crane roller rockers.  When I took the carb off I looked into the intake (Weiand) and you could see some porting had been done.  Also has a Bassett pan and new twisties.  All braided lines with a stinger ingnition (havent heard of it).  Anyways if you have any input I would appreciate it!!
Title: Re: Carb issues pt. 2/Holley 4160 750 cfm
Post by: Danger731 on May 11, 2011, 12:34:49 PM
Congrats, don't forget to use a real good fuel filter for all that patience and hard work !
Title: Re: Carb issues pt. 2/Holley 4160 750 cfm
Post by: 79charger on May 15, 2011, 05:56:01 PM
Hey Gromet , When you heading out to Echo Lodge again ???
Title: Re: Carb issues pt. 2/Holley 4160 750 cfm
Post by: Steel Gromet on May 18, 2011, 08:10:01 PM
Whats up Charger?  No plans yet, but maybe cruise out to Blythe a few times.  Got any trips planned?
Title: Re: Carb issues pt. 2/Holley 4160 750 cfm
Post by: 79charger on May 19, 2011, 01:19:24 PM
Be out at echo weekend after memorial with some Jetboat guys , Never been down to Blythe with my boat , How is it compared to the Parker strip?
Title: Re: Carb issues pt. 2/Holley 4160 750 cfm
Post by: Steel Gromet on May 23, 2011, 10:53:39 PM
Probably not as rough, but havent been out there this year.  Been missing all the trips working weekends.  Pus its only 2.5 hrs from mi casa.
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