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Jason, Marine Mechanic
Category: Marine Electronics
Satisfied Customers: 500
Experience:  Degree in Marine Technology, Also Certified with Mercury Marine, MCM, MIE, VP, Yamaha, Honda, Suzuki
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I have a 1986 mer 115 with 3 carbs. I took it twice to a guy

Customer Question

I have a 1986 mer 115 with 3 carbs. I took it twice to a guy who is supposed to be a great mechanic, haha. It runs great wot, but, absolutely will not idle for very long, when you unload it from the dock, and try to give it a little throttle, it will die or sputter and die. The mechanic put new kits in all the carbs, told me not to touch it! well, I didn't touch it, he put new wires, plugs, checked everything I tested a lot of things also, the motor has great even compression on all 6 cylinders too. He told me the motor is in great condition. I am about ready to sell it and just buy a new motor. I am asking you and maybe trying one more mechanic, then im done. any suggestions?
Submitted: 5 months ago.
Category: Marine Electronics
Expert:  Jeff_Gr replied 5 months ago.

The timing and sync of the carbs to the timing has to be correct, what is your engine timed to?

Look at the float bowls on the top, side of the carbs is there a small brass air jet in the cap next to a small hose?

Where are the idle mixture screws set at? Turn them in slowly counting how many turns until they lightly seat. One 1 1/2, 2 turns?

What is your compression?

Customer: replied 5 months ago.
My idle screws are at 1 3/4 turns out I forget the exact lbs. But according to the book it is only about 20 lbs. Or less than the very top when new, the mechanic did the compression also and he measured almost exactly what I did. I know the carbs have to be synched together and they are. I have done everything I COULD MYSELF then took it to the supposed top old metc. Guy in Salem, Oregon, and when I got it back, it would idle so so and after the first outing which was nominal at best, ***** ***** running the same way, falling flat at going from idle to quarter to half throttle. I have spent 600 bucks , new carb kits once MYSELF, once the mechanic, and this is why I'm asking before I dump it. I know it is a sound motor there is just something were not catching.

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