motor wont start when hot??

millerfiller

Recruit
Joined
Apr 1, 2009
Messages
1
i have a 1979 johnson 50 hp tiller manual start motor that when it gets up to operating temp it wont start....model #50RL79C / serial # c 8045174 . i believe its a commercial motor that was used in the coast gaurd. it runs great and starts when cold within 2 to 5 pulls. would it be possible that it is the coil or power pack ?? any help would be appreciated. !!
 

Mas

Lieutenant Commander
Joined
Oct 3, 2006
Messages
1,656
Re: motor wont start when hot??

Test the spark when at temp...make sure the spark and jump a 7/16 gap with a spark tester.

MAS
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: motor wont start when hot??

Sounds like the pack if you have no fire at all. Try starting it on muffs and point a hair dryer real close to the pack and see if it dies faster than is usually does.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: motor wont start when hot??

have to agree 99% power pack, is heating up and failing. let it get warm enough to cut off, check spark on both cylinders, if you have spark on one, swap the coils, and see if the problem follows the coil, if so replace the coil. if you have no spark on either, or the problem stays with the cylinder, replace the power pack.
 
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