1979 115hp Johnson HELP!

sgtallen414

Cadet
Joined
Jun 12, 2019
Messages
7
I have a 1979 Johnson 115hp. I changed the impeller. Put new plugs in. I took it out for the first time yesterday. It would not idle very well. so I turned up the idle about 2 turns. after that I ran on the lake for about a hour. worked perfect. stopped to fish that is when every thing went bad. The boat will idle and I can run bring it up to 5k rpm, and 5k rmp in revers but it will not go over 2k rpm in forward motion full throttle. Ran like this for about a hour the stalled on me. Acted like the battery was dead. I pulled the plugs out and the motor turned right over. Put the plugs back in and the motor would barley turn. So I think the timing is off, but why would it only go 2k rmp in forward motion?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,501
How long hqave you owned this motor ?----Start with a compression test.------Check the flywheel key.------Load test the battery.-------Pull starter apart for inspection.-----Check lower unit oil.------Not much money spent to doo these inspections.
 

sgtallen414

Cadet
Joined
Jun 12, 2019
Messages
7
I just bought it about 3 weeks ago. I also put in new battery, starter, and changed the lower unit oil.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,501
It is 40 years old.----The compression test is important.---Get the new battery load tested.-----A factory replacement starter or something else from an online source ??
 
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