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1989 Mercury 70hp 3 cylinder intermittent running problem

Tim Jenny

New member
I'm having problems with it bogging down at times and other times it runs great, Sometimes it will do this then just kick in and run great for a while. Very hard to pin down, Ive checked for spark and have it at all 3 cylinders. very frustrating problem.
 
Alright I'll check for spark at the plugs when it bogs down and if it has good spark I'll turn out the idle mixture screws.
Thanks Guys
P.S. If you have any other ideas I'm all ears.
 
Well I think I've located/solved the problem, on my ignition switch if you push the key in while turning it over it engages the choke. This seemed to be sticking or staying on. I went to a marine dealer and he called it a enricher solenoid I replaced that and it ran great the rest of the week.
I don't know if this is a common problem or not but the Mercury dealer up there in Northern Minnesota had one in stock so they must go out occasionally . Has anyone else experienced this problem. Hopes this helps someone.
Thanks Tim
 
I've seen that happen before (and I'm sorry I didn't think of it). That solenoid rotates a 'valve' on each carb to send extra gas to the motor for starting. If they don't shut properly, even with a good solenoid, the motor will load up at low speeds so make sure they are shutting all the way.

Jeff
 
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