Go Back  Offshoreonly.com > Technical > General Q & A
What would make Carb overflow when hot? >

What would make Carb overflow when hot?

Notices

What would make Carb overflow when hot?

Thread Tools
 
Old 09-01-2010 | 12:54 PM
  #1  
Thread Starter
Registered
20 Year Member
 
Joined: Nov 2003
Posts: 2,296
Likes: 3
From: Lake Travis ,Texas
Default What would make Carb overflow when hot?

Its an HP500 carb, we have already rebuilt it, set the float levels multiple times and it keeps doing same thing,
once you have been out running for a while and idle down to dock it will sputter and be way rich, as you look down carb bores you can actually see fuel trickling out of tubes. Makes it a scary propisition to dock.
When its cold it does not do this, idles perfect , nice 13.9-14.1 AFR , no fuel dripping.
Driving me bonkers..
Its sitting on a Ebrock Victor Jr with no heat passges so intake stays relatively cool.
HTRDLNCN is offline  
Reply
Old 09-01-2010 | 01:36 PM
  #2  
Registered
 
Joined: Feb 2009
Posts: 319
Likes: 0
Default

Replace the needle and seat. If it is a brass float be sure it has no fluid inside.
Boat1 is offline  
Reply
Old 09-01-2010 | 06:44 PM
  #3  
blue thunder's Avatar
Registered
20 Year Member
 
Joined: Nov 2001
Posts: 3,393
Likes: 6
From: IBX
Default

How much fuel pressure when this happens?

Last edited by blue thunder; 09-01-2010 at 06:46 PM.
blue thunder is offline  
Reply
Old 09-01-2010 | 08:22 PM
  #4  
Registered
20 Year Member
 
Joined: Jun 2004
Posts: 1,948
Likes: 37
From: Omaha, Nebraska. Boat on the Mighty Mo! Longest river in the USA!
Default

I had a Holley 800 do the same thing this spring. You could look down it and see gas pouring out. I just took the one bowl off cleaned it, set the level while the engine was running and never another issue.
1BIGJIM is offline  
Reply
Old 09-01-2010 | 09:00 PM
  #5  
Registered
15 Year Member
 
Joined: Mar 2007
Posts: 936
Likes: 9
From: New Jersey
Default

Check the floats to make sure they are not filled with fuel.Also have you replaced the fuel pump with a higher volume. Those needle an seat cant take any more than 7 lbs .
excalibur82 is offline  
Reply
Old 09-01-2010 | 09:23 PM
  #6  
Banned
 
Joined: Mar 2008
Posts: 981
Likes: 0
Default

Originally Posted by Boat1
Replace the needle and seat. If it is a brass float be sure it has no fluid inside.
Yep what he said !!! Even if they look good , which they will replace them .
Jeff P31 is offline  
Reply
Old 09-02-2010 | 07:58 PM
  #7  
Thread Starter
Registered
20 Year Member
 
Joined: Nov 2003
Posts: 2,296
Likes: 3
From: Lake Travis ,Texas
Default

not the vent tubes, it leaks out the venturi where fuel normally comes out when it is running.
Stock fuel pump.
Only does it after it warms up so if it is the float wouldnt it do it all the time?
Thanks!!
HTRDLNCN is offline  
Reply
Old 09-02-2010 | 08:35 PM
  #8  
Thunderstruck's Avatar
Charter Member
 
Joined: Nov 2000
Posts: 1,094
Likes: 0
From: Lake Charles, LA USA
Default

Bad Power valve? Idle not adjusted properly so that low idle vacuum lets the power valve open??
__________________
Long time cult member.
Thunderstruck is offline  
Reply
Old 09-02-2010 | 09:08 PM
  #9  
Thread Starter
Registered
20 Year Member
 
Joined: Nov 2003
Posts: 2,296
Likes: 3
From: Lake Travis ,Texas
Default

replaced power valve
good idle until it heats up and good vacuum.
Frustrating.
HTRDLNCN is offline  
Reply
Old 09-02-2010 | 09:40 PM
  #10  
Platinum Member
 
Joined: Dec 2002
Posts: 2,195
Likes: 2
From: Dallas, TX
Default

Try calling the Holley tech line
BenPerfected is offline  
Reply


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.