1975 850 No hot start

[phoenix37]

Had to get towed back to the dock yesterday. My 85hp mercury ran great all day and would start right up after stopping for short periods of time trying to find fish. We finally found a good spot and stopped for about a half hour. Tried to start the motor to head home and no signs of life. Seemed like it wasn't getting spark. I tried everything I could think of and finally ran the battery down trying to get it to kick over. Charged the battery overnight and went out this morning and it started right up without a problem. What am i missing?

 

[merc850]

Re: 1975 850 No hot start

That sounds like the trigger is crapping out, open the cowling and check for bad wiring at the harness and switchbox first, then use the test method on this site. I have the same motor and it had the trigger problem.

 

[phoenix37]

Re: 1975 850 No hot start

Thank you. ill give that a try.

 

[MH Hawker]

Re: 1975 850 No hot start

I would guess its a heat soak problem, its not common but it happens, Run the ohm meter tests on the components.

 

[Fed]

Re: 1975 850 No hot start

Re: 1975 850 No hot start

After half an hour I'd treat it pretty much as a cold start, a bit of fast idle & ready to hit the choke if it didn't fire within a couple of revolutions.
Don't expect a half hour restart to be the same as a 5 minute one.
They cool down very quickly in the water, this advice was given to me by a wise old Mercury dealer when I got my first outboard and it has always worked for me.