1978 Johnson 70hp "runaway motor"....now won't turn over(Solved!)

BonairII

Commander
Joined
Jun 7, 2011
Messages
2,727
Installed a new(used) PP on the motor today. Spark on all 3 cyls now. Hooked up fuel and test fired it. It immediately "ran away" and the motor SCREAMED! :eek::eek::eek: Probably hit 10K+ rpm

I pulled all 3 plugs in a matter of a couple seconds(did it so violently that I pulled 2 wires right from the coils themselves).

I went to turn motor over after the "runaway" and now I get nothing(starter isn't getting juice). The electric choke IS working, but nothing from the starter. I checked the fuse at the back of the motor and visually it looks good.

What could have gone wrong? :confused:
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: 1978 Johnson 70hp "runaway motor"....now won't turn over

Re: 1978 Johnson 70hp "runaway motor"....now won't turn over

Throttle wide open??? I don't know if that one has a throttle/starter lockout or not.
 

BonairII

Commander
Joined
Jun 7, 2011
Messages
2,727
Re: 1978 Johnson 70hp "runaway motor"....now won't turn over

Re: 1978 Johnson 70hp "runaway motor"....now won't turn over

Throttle wide open???

Yup, throttle was wide open(controls were screwed up somehow). I'm going to run the throttle manually until I get that sorted out.

My question was referring how the 'runaway' could have caused the starter not to get juice now.
 

BonairII

Commander
Joined
Jun 7, 2011
Messages
2,727
Re: 1978 Johnson 70hp "runaway motor"....now won't turn over

Re: 1978 Johnson 70hp "runaway motor"....now won't turn over

Problem solved!

The culprit was the neutral safety switch. In my panic to pull the plug wires(and avert a blown motor), I bumped into the gear lever. It was about 1/4" forward of neutral.

Now on to figuring out why my fuel is dribbling out the bottom carb. :mad: I just pulled the carbs an hour ago to clean the carbs and reset the floats. I found a small amount of trash in the seat, so I figured I had the problem solved....but of course, I couldn't be that lucky. :(
 
Top