outboard problem

B

Bethelcock

Recruit
Joined
Nov 7, 2012
Messages
1
I have a newly rebuilt 1993 Johnson 50 HP. Yesterday, during the breakin sequence, the engine throttled down from about 4500 RPM to about 2000 RPM. The control was still in the nearly wide open position. The engine did not run hot and was not skipping. I managed to cruise at a good trolling speed back to the landing. The engine cranks and idles smooth. There is plenty of fuel in the tank. The carbs were rebuilt and the fuel lines are new. Any suggestions are welcome.
 
64osby

64osby

Admiral
Joined
Jul 28, 2009
Messages
6,826
Re: outboard problem

Not a lot of info to go on.

Need to start at the beginning. Compression check, check spark on all cylinders, check fuel pump, check carbs.

Sounds like you lost spark on a cylinder or two or have a fuel delivery issue, pump or high speed clogged, would be my guesses.
 
B

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: outboard problem

Do a cyl drop test on it and see if it's running on both cyls.
 
nwcove

nwcove

Admiral
Joined
May 16, 2011
Messages
6,293
Re: outboard problem

does that motor have the "system check" on it?
 
H

Home Cookin'

Fleet Admiral
Joined
May 26, 2009
Messages
9,715
Re: outboard problem

If it didn't run rough, you may have had an oil/overheat warning. Some motors drop speed automatically; they are supposed to sound an alarm, too, but odds are the alarm was not hooked backup or is defective. Test the alarms.

Hope that's it b/c that's the symptom of a motor half-seizing. If this is an option I'd take it straight back to the guy who rebuilt it before you start wrenching on it.

I nearly lost a rebuilt motor due to a faulty oil hose (VRO) that luckily I checked before running.
 
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