Got her running cant keep her running

[labrooker]

ok so i got the boat running would like for someone that i have talked with about this motor before to respond. its a long story lol. starts fine and runs smooth with half throatle. but if i back off the gas it just dies and if i give it more gas it does nothing. and only will stay running for about 30-45 secs each time. but each time starts right back up just fine any ideas where to start. im gonna replaced wires havent done that yet. also the coil wire is visuallly arching to the coil housing im assuming a bad wire or maybe a crack in the coil housing? If u want a lil backround what i did to this motor check my other posts

 

[jerryjerry05]

Re: Got her running cant keep her running

What are we working on?It could be a coil or a shift cable.More info please.J

 

[labrooker]

Re: Got her running cant keep her running

ok heres what i did... had a 92 4.3 mercruiser with a cracked block.... got a new motor from the junk yard.. didnt realize the motor i got from the junk yard had a balance shaft... been told by many that it wont work but i was already too deep in the rebuild to start over lol. everything seemed to go togeather just fine. so i got a 92 4.3 balance shaft block with the balance shaft removed. i used every thing from the marine motor ...(pistons crank heads intake ect.. everything) ecept the camshaft i couldnt use the marine camshaft.

 

[labrooker]

Re: Got her running cant keep her running

oh ya and i also had to use the timing cover from the auto motor because the front of the block was a little different because of the balance shaft... so i had to remove the marker on the cover for setting the timeing because the harmonic balancer on the automotive motor was a smaller diamater than the marine one and the marine harmonic balancer wouldnt go on...... figured it was important to use the harmonic balancer that was set up for that crank.

 

[Lyle29464]

Re: Got her running cant keep her running

I think you have scared off all the good mechanics so your stuck with the weekend shade tree type like me that have no reputation to defend.

I dont know if the mix match of parts will work and for how long but here goes.

I think you have 2 problems besides the odd parts.
#1 not enought fuel. I would check to see if your pump is providing plenty of fuel. It sounds like that is part of the problem. If the pump is ok you need to look at the carb.

#2 I do not think your coil is bad. The spark is jumping because that path is better than the normal path. Look into you dist cap and see if it is a mess. Look at rotor and see if it is the right size and if the end is messed up and where it contacts the top of the cap.
Look at the contacts where your wires plug into the dist. look at the end that attaches to your plugs and check the plugs to see if they are correct and in good shape. You may need plugs,wires,cap.and roter. That is why it will not run at low speed. The fuel is the high speed problem. Yes all of this is a guess.

 

[labrooker]

Re: Got her running cant keep her running

haha scared off all the good mechanics lol.... well ill check all that out... i dont think it is the rebuild....miss matched parts... because #1 it will run ......and #2 it had these similar simptoms before i pulled it all apart... at that time i just assumed it was the cracked block.... guess not.... ill keep troubleshooting see what i can figure out

 

[labrooker]

Re: Got her running cant keep her running

also above u said shift cable? what did u mean

 

[ebear]

Re: Got her running cant keep her running

sounds like a carb problem. bypass your shift switch just in case the cables are stiff and binding. check if that helps. [Don't forget to rehook it up] check fuel pressure. If you have fuel, rebuild the carb.