merc 65HP dies under load

[avenger79]

Figured the best place to get help with this was right here. Just had the carbs and fuel pumps rebuilt on a '68 merc 65HP. Since getting it back, it runs great ----- in neutral. When I put it in gear it would die right away. I found a hose not connected to dist, looked like a vent. Hooked that up and now it will run in gear, but I tried to pull a skier and as soon as the weight hit the boat. engine died. Once it dies it takes forever to get going again, then you have to play the I don't want to go when in gear game again.

Any thoughts.

 

[Yepblaze]

Re: merc 65HP dies under load

Since you "Just had the carbs and fuel pumps rebuilt"
Take it back.

I'd suspect fuel starvation, BUT....

It's not impossible to have some other issue causing it.

Perhaps you can have someone squeeze the primer bulb as you try to accelerate. if it corrects the problem it's fuel starvation and what they did needs to be redone.

 

[Flyinorchids]

Re: merc 65HP dies under load

Had same problem with my mariner 200s. I advanced the idle timing,and solved the problem.

 

[avenger79]

Re: merc 65HP dies under load

Since you "Just had the carbs and fuel pumps rebuilt"
Take it back.

I'd suspect fuel starvation, BUT....

It's not impossible to have some other issue causing it.

Perhaps you can have someone squeeze the primer bulb as you try to accelerate. if it corrects the problem it's fuel starvation and what they did needs to be redone.

I had heard this from guys at work as well so last night I called the shop and explained the issue. For only $100 he'll take a look at it and determine if it was their fault or not.

Probably won't be doing business there again. Many people seem to agree with Fly it's probably not timed right and seeing as the shop says they don't run the motor under load while there apparently they didn't time it while in gear. Guess I'll be learning about this motor after all.
Funny part is I had all but signed a contract on a new boat at the shop. I'll be calling the saleman today to tell him it won't be happening.
It took a long time to find a bike shop that was proud of their work and really cared about customer service in this area, apparently it will take a while to find a boat shop as well.
At least it's closer, it does run while in neutral and if I mess with it I can actually run it around the lake.

 

[Yepblaze]

Re: merc 65HP dies under load

Don't force it to run around if it is experiencing a lean condition.

It will burn the piston(s).

 

[Chris1956]

Re: merc 65HP dies under load

Avenger, The motor may be timned in gear or just cranking, it makes no difference. The idle mixture must be set under load. It is likely this was not done by the shop.

You should test the idle timing at idle pickup and at WOT to see that it conforms to spec. That motor is pretty old for any shop to have experience with, so ignorance may have ruled the shop.

 

[avenger79]

Re: merc 65HP dies under load

Avenger, The motor may be timned in gear or just cranking, it makes no difference. The idle mixture must be set under load. It is likely this was not done by the shop.

You should test the idle timing at idle pickup and at WOT to see that it conforms to spec. That motor is pretty old for any shop to have experience with, so ignorance may have ruled the shop.

Thank you, will have to check it out. Actually the service writer and I were joking around that the motor was older then the tech who worked on it.