loss of power on 140 hp

J

JonRiley56

Seaman Apprentice
Joined
May 24, 2005
Messages
31
Hi,

I have a 1972 140 hp johnson that has been very reliable. I had it out tonite and it was fine idling out of the marina, but when i got out onto the bay and it warmed up it lost power and started making what I can best describe as a whining noise.

I dont know where to start to try and diagnose it, any help would be appreciated.

thanks

jon
 
HighTrim

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: loss of power on 140 hp

Trying to think of a "whining noise"

A spun prop perhaps? Sound like it may be over revving a little? Best way to test this is to draw a line across the hub and prop, run the motor until you hear it "rev", pull it out and inspect the lines. If they are no longer lined up, the hub is spun, and can be rebuilt.

Short of a spun prop, you may be dropping a cylinder once a particular ignition component heats up. Spark test could verify this. But that does not explain the noise.
 
jimmbo

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,961
Re: loss of power on 140 hp

What year was that again?
 
You must log in or register to reply here.
Top