Boat Starting Problem

[bugup]

I have a 1995 Mercruiser 4.3LX with a 4 barrel and Thunderbolt IV ignition. I am not sure what the problem with it may be, however, it is hard to start when cold. It will start first crank initially after 2-3 shots of prime, however, will only run at idle for a minute or so and then die. This is when the fun begins. In order to get it to fire again I end up cranking and cranking the starter and then finally it will fire and I have to immediatley get it up to about 1500 rpm or else it will die again. Once the temp is up to 100-150 it is fine afterward. You can shut it off and and start it no problem as many times as you like as long as it doesn't sit for more than an hour or so. If anyone has any ideas it would be great. I think it may be a problem with the choke , however, not sure.<br /><br />

 

[Don S]

Re: Boat Starting Problem

Have you ever run an engine with a carb before, or have you always had EFI?

 

[Haut Medoc]

Re: Boat Starting Problem

Sounds like a choke problem for sure. When it dies, (first time), pull the flame arrester and look at your choke. If it is still closed your choke needs to be adjusted...JK

 

[waterone1@aol.com]

Re: Boat Starting Problem

It could also be a bad fuel pump or something in the supply line causing it to loose prime. Next time it dies durring the first minute, pull the flame arrestor, have someone push the throttle down a few times (ignition off) while you look for jets of gas in the carb throat(from the accelerator pump). If you don't see any gas squirting, the float bowl is empty. Check all of your hose clamps and connections between the fuel pump and fuel tank.

 

[bugup]

Re: Boat Starting Problem

Don S<br /><br />Actually this is my first carburated engine because all my previous vehicles have been EFI.

 

[Don S]

Re: Boat Starting Problem

Starting and keeping a carbed engine running usually takes some throttle pumping depending on how the choke is set. Even after it starts you may have to keep the revs up to 12 to 1500 rpm too keep it going.<br />They are nothing like EFI. You may also need a tuneup if it's getting to hard to start, and some choke and carb adjustments.