omc new carb won't idle

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ldshrk

Recruit
Joined
Jun 28, 2006
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2
Have a 351 ford omc.Had old carb rebuilt by carb shop and it wouldn't idle.Adjusted floats and still idled rough,since carb was 30yrs old I decided to go and buy new holley 600 marine carb.Put new carb on and same problem.Put it in neutral and rev it up a couple times and it will idle for about 30 sec and run rough and then dies.It will idle fine while sitting at dock but soon as it gets into gear same problem.
 
P

Purduebarry

Petty Officer 1st Class
Joined
Sep 29, 2005
Messages
378
Re: omc new carb won't idle

Wow, that's an expensive way to troubleshoot. I'd look at all of the gas supply issues, sounds like the motor is starving at low RPM. Gas pressure, fuel pump, fliters, anti-siphon, water seperator, blockage, crud, water in the gas, old gas???
 
L

ldshrk

Recruit
Joined
Jun 28, 2006
Messages
2
Re: omc new carb won't idle

The problem is that I smell gas when it starts running rough so I know I'm getting fuel.
 
F

fendersfender

Petty Officer 1st Class
Joined
Mar 23, 2005
Messages
317
Re: omc new carb won't idle

When is the last time a complete tune-up was done? If all else is well (plugs, wires, cap, rotor, points, etc.) then maybe idle mixture screws need to be adjusted......sounds like its just running rich at idle
 
Reel Poor

Reel Poor

Vice Admiral
Joined
Jan 29, 2005
Messages
5,522
Re: omc new carb won't idle

I would recommend a compression test or leakdown test, and also check for vaccum leaks around the intake manifold.
 
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