Merc' just stops!

davepring

Cadet
Joined
Feb 10, 2003
Messages
15
I have a 25hp Mercury outboard (1987) My problem is that the the last three times out it has just stopped, no cough or splutter it is almost as though the ignition is switched off. Once this has happened it will not start unless left for 30mins+. (we had to be towed in this weekend). I have checked the sparks which are fine. There was some muck in the fuel filter, but no more has appeared. On each occasion once restarted everything has been fine. (This weekend it ran for 3hrs when restarted). The time to each stop has varied - 2mins, 5mins and 30mins. When starting from cold it takes no more than two pulls to fire up. Can anyone help shed some light on this please?
 

ve25dc

Recruit
Joined
Jul 6, 2003
Messages
1
Re: Merc' just stops!

Sounds just like problem I had last summer. It ended up being an intermittently shorted ignition coil.
 

trumpetbucks

Petty Officer 2nd Class
Joined
Jun 2, 2003
Messages
140
Re: Merc' just stops!

I think Dan C has given you a big clue: it definitely sounds like an intermittent electrical problem, now you just have to trace it down.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Merc' just stops!

I had a small Johnson 7.5 do the same thing. Turned out to be a floater in the carb bowl. It would get sucked into the main jet, effectively shutting off the fuel. Motor would die without so much as a sputter. After sitting for a bit the floater would settle out of the jet and the motor would start up fine. Turned out the gasket that seals the carb bowl to the carb body was rotted out and small chunks were breaking off. Cleaned carb, replaced gasket, no problems since...<br />- Scott
 

maillon

Seaman
Joined
Dec 21, 2002
Messages
68
Re: Merc' just stops!

Had a similiar problem with a small merc outboard.<br /><br />It turns out that the ignition coil was arching.<br /><br />I didn't find this out until I brought to a good Merc Mechanic.
 

davepring

Cadet
Joined
Feb 10, 2003
Messages
15
Re: Merc' just stops!

Thanks all, I think it's time to visit my friendly local mechanic. Diver
 

Maximerc

Petty Officer 1st Class
Joined
Jun 26, 2003
Messages
292
Re: Merc' just stops!

Check to make sure the fuel tank is Vented !!
 
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