35hp 1987, 1 cylinder working

JayRd7

Cadet
Joined
Aug 12, 2006
Messages
8
Hi,
I have a 1987 Marvac 14 foot boat with a 1987 35hp oil injected Mercury outboard, 2 cylinders. The motor seems to run fine, but when it starts up in the water only 1 of the 2 cylinders is running. After about 10 minutes or so of running the boat in the water (at half speed of course) the other cylinder will randomly kick in and start running and the boat will be able to get up to full speed. Sometimes though, when the 2nd cylinder is running, it will give out and the boat will go back to 1 for a few minutes, then it will randomly kick in again. Any ideas? I think it might be an electrical problem, maybe in the power pack? When both cylinders are going the motor runs smooth, but sometimes theres only 1. Thanks for your help,

JayRd7
 

JayRd7

Cadet
Joined
Aug 12, 2006
Messages
8
Re: 35hp 1987, 1 cylinder working

JayRd7 said:
Hi,
I have a 1987 Marvac 14 foot boat with a 1987 35hp oil injected Mercury outboard, 2 cylinders. The motor seems to run fine, but when it starts up in the water only 1 of the 2 cylinders is running. After about 10 minutes or so of running the boat in the water (at half speed of course) the other cylinder will randomly kick in and start running and the boat will be able to get up to full speed. Sometimes though, when the 2nd cylinder is running, it will give out and the boat will go back to 1 for a few minutes, then it will randomly kick in again. Any ideas? I think it might be an electrical problem, maybe in the power pack? When both cylinders are going the motor runs smooth, but sometimes theres only 1. Thanks for your help,

JayRd7


Just to add that both sparkplugs have recently been replaced and are fine. This has been an ongoing problem for several years now...
 
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