Johnson 50 2stroke Starting issue

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,080
Yeah... I'm wondering.
Just did a quick check.
Neutral: prop spins freely
fwd: prop is locked
rev: prop is locked
return to neutral: prop spins freely

Probably doesn't tell much... but posted here.
Your not understanding how an outboard works. Whether the prop turns in gear or not has nothing to do with an engine issue. You ask for help, why not follow the recommendations to find your problem. ?
 

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,640
I have a four and a half deluxe sitting in my garage right now. I can spin the flywheel one way until it stops and I can spin it back the other way until it stops, it's got a broken rod and the crankshaft is coming around and smacking part of the rod that's not moving. If you lean the motor backwards and get the Piston to slide down then you can spin it all the way but the Pistons not moving so that's the problem. If you try to do a compression check it shoves the Piston back and re-locks up.

There really is no big mystery here. The fact you can't easily spend it with your hand with the plugs out tells me that Pistons are partially seized or the bearings or something or other so pretty sure your power head is fried.
 

Nordin

Commander
Joined
Jun 12, 2010
Messages
2,555
The thread says Johnson 50 2 stroke.
Modelnumber?
Early 70.es (71 and up) loop charged "looper" OMC 50-55Hp was known as "explode motor".
They shoot a hole or a crack into the crank case when the connecting rod or the piston broke.
I have had some of those engines and sometimes it is hard to see the crack in the crank case if do not look very close.
 

LincolnLog

Cadet
Joined
Oct 26, 2024
Messages
10
The thread says Johnson 50 2 stroke.
Modelnumber?
Early 70.es (71 and up) loop charged "looper" OMC 50-55Hp was known as "explode motor".
They shoot a hole or a crack into the crank case when the connecting rod or the piston broke.
I have had some of those engines and sometimes it is hard to see the crack in the crank case if do not look very close.
I'll have to look more closely. It's a 1990.
 
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