no spark

[mark sprayberry]

1994 or 05 70 hp mercury force today boat cranked and ran for 5 min's then it shuts off like someone turns off key
restarted in fired right up ran for 5 mins and shut off again now i have no spark

 

[pnwboat]

Re: no spark

If you have access to, and know how to use an ohm meter you can do some basic trouble-shooting using the following guide. See the section for 3 cylinder engines 1992 - 1997. Make sure the kill switch is not defective and grounding out the ignition.

http://www.boatpartstore.com/page11.asp

 

[mark sprayberry]

Re: no spark

checked the kill switch ignition and everything under dash all is okay and in good shape. I dont understand about ohms meter. I went out three days after this post hit the key boat started right up after 5 mins it shuts off and no plugs will fire at that point no spark the engine will turn over but will not start. before my problem started we were out fishing and the motor ran great but would not open up all the way, not missing just would run wide open, could this be the stater or coils shuting off when motor gets warm. Is their a emergency shut off on the motor so it wont blow engine

 

[pnwboat]

Re: no spark

Sounds like something is failing after it warms up. The ohm meter is your best bet to solving the problem without spending money needlessly.

You can eliminate a short to ground in the ignition kill circuit by disconnecting the black/yellow wire from the switch box and try starting it when it acting up. This totally disables the kill circuit. NOTE: Since this disables the kill circuit, the only way to shut the motor off (if it starts) is to either choke it until it floods out and stalls, or pull the plug wires off the plugs.

I would suspect either the switch box or the stator since you're loose spark to all the plugs.

You mentioned that just before it went out it would run but not at full speed. Some of the Thunderbolt ignition system stators have a separate low speed winding and a separate high speed winding. I wonder if you lost the high speed winding, and now the low speed winding is also going out?

The ohm meter is your best friend in this type of situation. It will tell you if the stator windings are good or bad. The only bad thing about changing the stator if pulling the flywheel. Sometimes they can be difficult to remove.