4.3 hard starting when hot

M

Mikegue

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Sep 2, 2007
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I have a 1991 4.3l cobra drive. It starts up relatively easy when cold but, once it is hot, I have a difficult time starting. If I hold the choke closed I can usually get it to start. I have replaced the water seperator, spark plugs, wires, cap, rotor, and pumped some water out of the fuel tank and had the carb rebuilt. The fuel line does not feel hot. PLease send your advice I am at a lost as what to do next. Thanks.
 
Gary H NC

Gary H NC

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Dec 1, 2005
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8,972
Re: 4.3 hard starting when hot

Any signs of fuel leakage under the float bowl? With the engine warm no choke should be needed.Sounds like the float bowl is leaking fuel down.
The Rochester carbs have plugs in the bottom of the bowl that are known to leak.During the rebuild they should be sealed with epoxy.
Did the problem exist before the carb was worked on?
 
M

Mikegue

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Re: 4.3 hard starting when hot

I have a holly carb. I also had the problem prior to the rebuild. Prior to it being rebuilt, I noticed that the carb. was still pumping gas after I stoped cranking. When it was rebuilt, the mech. said the accelerator pump was sticking. The boat runs great with the exception of trying to start it when it is hot. Thanks.
 
G

gvarney13

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Jul 1, 2007
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Re: 4.3 hard starting when hot

I had the same problem prior to rebuilding my carb, but I also had to re attach the coil in the choke it had come loose and I haven't had a problem since.
 
M

Mikegue

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Re: 4.3 hard starting when hot

I does not leak gas since I had the carb. rebuilt. I was explaining what it used to do. Sorry for any confusion
 
180shabah

180shabah

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Mar 26, 2005
Messages
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Re: 4.3 hard starting when hot

There shouldn't have been any confusion, I just can't read:D


You may also want to verify your initial timing, Mercruiser is 8deg. BTDC, OMC should be close, double check with your manual. If it is advanced too far, it can make it hard to start. You should also recheck all carb/choke settings, just because it was rebuilt doesn't mean it was properly set up when it was reinstalled.

Good luck
 
M

Mikegue

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Sep 2, 2007
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Re: 4.3 hard starting when hot

Thanks for the info. I looked into the carb when it was not starting, it appears to be be dripping into the intake manifold. I am going to check the pressure on the fuel pump, if that is with in specs, i'll check the float of the carb. I'll keep you posted
 
M

Mikegue

Recruit
Joined
Sep 2, 2007
Messages
5
Re: 4.3 hard starting when hot

Just an update, went out on the boat the last couple of days. After I turn the boat off, I put it in WOT. I have not had trouble since doing this. I was talking with my friend who rebuilt my carb. I asked him what type of float was in the carb, he stated it was the black plastic type. I've read that these absorb gas and don't work properly after a while. I plan to replace the float and hopefully my problem will be solved. If you have any further advice or suggestions please reply. Thank you for your help.
 
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