Merc 350 260hp fuel issues?

[dremmick85]

I have a 91 ski supreme with a chevy mercruiser 350 engine. I just got the boat back from the mechanic who took apart an cleaned the rochester quadrajet, set timing checekd compression etc. When i drove the boat from the boat landing to my dock it ran perfectly. 10 mins later i got back on the boat and it struggled to start. I could get it to start in neutral with the throttle slightly forward but then the rpm's fell and the engine died. Once it starts as soon as i put it in gear it dies. Well here is the kicker that next morning i went to start and it started right up. drove it around for a 20min. 10 min later i went to start it and the same symptoms occured as before. What i found weird is if i let the boat sit for multiple hours it will start up fine, but once i let it sit for a few minutes after driving i can barely keep the engine running. Possibly excess fuel in the bowls?

 

[HT32BSX115]

Re: Merc 350 260hp fuel issues?

Howdy ,welcome to iboats!

I just got the boat back from the mechanic

You really should take it right back to him and let him trouble shoot his work.

I can think of several carb-related things I would check but knowing that someone had it apart, (and I payed him for it) I would look to him first.

I'll assume that he put a "kit" in it? Did he adjust it properly? Float level, idle mixture, electric/heat choke setting, idle RPM, etc......


Cheers,


Rick

 

[djmakko]

Re: Merc 350 260hp fuel issues?

Same thing happened to me 4 years ago, I have the same motor with the Rochester Quadrajet, I bought a rebuilding kit and did it, and same symptoms as you, friend of mine that is a mechanic try to adjusted but he said that the needles were wore down , I found one online for like 200 bucks replaced it and no problem since, of course until something else broke , take it back to the mechanic if he can't adjust it sue him lol

 

[dremmick85]

Re: Merc 350 260hp fuel issues?

I bought a edelbrock 1409 and he said he would install it for free. I have had lots of problems iwth my quadrajet since i have owned the boat for 5yrs. The carb was professionaly rebuilt 2 yrs ago.

 

[dremmick85]

Re: Merc 350 260hp fuel issues?

Alrigh experts im still having the same problems with the boat. My mechanic installed a brand new edelbrock 1409 on my engine. It ran great right away. After about 20 mins of driving i let the boat sit for about 15 min and went to start it again and would not start. I could get it to start in neutral with increased RPM's but after a bit RPM's will start to fall and kill the engine. Once i put it in gear it kills instantly. So we performed a fuel pressure test, and compression test which were both good. So what could be going wrong when the engine is hot?

 

[dremmick85]

Re: Merc 350 260hp fuel issues?

bump!

 

[Bondo]

Re: Merc 350 260hp fuel issues?

Alrigh experts im still having the same problems with the boat. My mechanic installed a brand new edelbrock 1409 on my engine. It ran great right away. After about 20 mins of driving i let the boat sit for about 15 min and went to start it again and would not start. I could get it to start in neutral with increased RPM's but after a bit RPM's will start to fall and kill the engine. Once i put it in gear it kills instantly. So we performed a fuel pressure test, and compression test which were both good. So what could be going wrong when the engine is hot?

Ayuh,... So what are the Sparkplugs tellin' ya,..??

Are they wet or dry,..?? Colors,..?? Sparkin',..??

 

[dremmick85]

Re: Merc 350 260hp fuel issues?

Spark plugs are a nice coffee brown. Also they were faintly wet.