1980 Merc 115 overhets. (I think)

[Rads92]

My boat starts fine as the day begins but will not start after a few hours on the lake. I have to let the motor cool for a considerable amount of time before it will restart, and even then it is a little rough getting it going. What could be the cause of this problem?

 

[Laddies]

Re: 1980 Merc 115 overhets. (I think)

Does the water from the telltale steam or to hot to put your hand into--then it's the w/pump. If not you will need to ck for spark, if its OK then you may need to ck the hih speeds for a lean condition or the timing for to much spark advance

 

[emckelvy]

Re: 1980 Merc 115 overhets. (I think)

Upon failing to restart, have you checked for spark?

I'm betting you don't have any and I'm also betting a bad stator.

If you are having spark issues, take resistance readings on the stator when cold, then when warm. If the resistance values change considerably the stator is shot. I'm just working on a '76 850 that's doing this, starts and runs OK for a few minutes then no spark until it cools. Stator checked great when cold but resistance on the Low-Speed windings went haywire after it lost spark.

These are the values expected for a good stator, if you don't have a meter, you can pick up a perfectly useable one at Sears for under $20:

Blue-to-Red stator leads: 4500-6200 ohms;

Blue/Wht-to-Red/Wht stator leads: 5400-6200 ohms;

Red stator lead to powerhead ground: 125-175 ohms;

Red/Wht stator lead to powerhead ground: 125-175 ohms

For detailed instructions on how to diagnose stator issues, do a keyword search on this forum for "stator" and you'll be amazed at all the problems these Pesky Buggers have been causing!

This site has additional, good info regarding troubleshooting ADI-type ign's in general:

http://outboardparts.com/mercury/troubleshooting/troubleshooting10.htm

HTH............ed

 

[Clams Canino]

Re: 1980 Merc 115 overhets. (I think)

A good waterpump will pee strong at idle - end of that story.

Assuming it's not an ignition failure, your warm starting procedure is probably flawed. They are much harder to start cold then they are warm. Try pumping the ball to start with - a vaccum leak can make it lose prime.

-W