OMC 5.7L, starts, idles, then dies when accelerates, ideas?

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palmsolo

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Jul 9, 2006
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OK, I am just about ready to take my boat into a shop to see if they can solve my problem, but due to the boating season backlog and my own desire to fix the issue myself I wanted to post my problem to see if the online boating community could help me out.

I put new fuel in my 1989 Reinell/Beechcraft with 5.7L OMC I/O engine after the winter season. It started and ran fine last fall, but I neglected to start it up over the winter. It now will idle OK (not super like before), but as soon as I try to accelerate/increase the throttle it starts to make a sound like it is sucking air and will then die with too much throttle. It also starts to smell of gas and will smoke if I keep running and accelerating.

Here is what I have done so far; replaced the fuel filter, replaced the inline carburetor fuel filter, replaced the fuel pump, rebuilt the carb, and replaced the spark plugs.

I think I now have the entire fuel system covered and wonder if it could be an electrical/timing issue? Will replacing the distributor help? Should I do something with the timing that may help? Will replacing the cheap little condeser do anything for this situation?

Please let me know if you have any ideas. Thank you!
 
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Maclin

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May 27, 2007
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Re: OMC 5.7L, starts, idles, then dies when accelerates, ideas?

Do a full electrical tuneup (contact points, condensor, cap and rotor) including dwell and timing check so you will know where you are at on everything, especially since your engine uses a points type ignition. Make sure the rotor moves one way a little bit and snaps back, if not then the dsitributor may need work, but do the full electrical tuneup first, it is imperative.
 
L

Limited-Time

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Re: OMC 5.7L, starts, idles, then dies when accelerates, ideas?

Sounds like the accelerator pump (in the carb.) has gone bad. With out a hot tank or some serious soak time, a home spun carb rebuild is a crap shoot at best. I'd check into a remanned, or new carb.
 
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palmsolo

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Re: OMC 5.7L, starts, idles, then dies when accelerates, ideas?

I actually had the carb rebuilt at a shop after I took it apart to clean it the first time that didn't solve the issue. The carb shop ran it on their test engine and it ran like a champ so it is not a carb problem now.
 
H

HT32BSX115

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Dec 8, 2005
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Re: OMC 5.7L, starts, idles, then dies when accelerates, ideas?

palmsolo said:
I think I now have the entire fuel system covered//////SNIP//////
Click to expand...



No,

you don't.

You probably have an anti-siphon valve at the tank that could be plugged or restricted and an intank filter screen that could absolutely be partially plugged and cause this very problem.


Cheers,


Rick
 
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palmsolo

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Jul 9, 2006
Messages
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Re: OMC 5.7L, starts, idles, then dies when accelerates, ideas?

Thanks. I'll buy all the ignition parts tonight and check the timing on the engine too. There seems to be lots of fuel getting into the carb so I don't think I have a fuel restriction issue. We'll see how it goes.
 
H

happy_flyer

Cadet
Joined
Oct 9, 2007
Messages
16
Re: OMC 5.7L, starts, idles, then dies when accelerates, ideas?

What would explain the smoke as described ? I ask because I have had the same problem...once in a while it comes back, usually if I have not let the engine warm for 10 minutes or so then run at 3000rpm or more...
 
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