1971 50hp johnson....need advice

LAKEHOME

Cadet
Joined
Dec 14, 2012
Messages
8
Motor has been running great after a new starter, solenoid, plugs, wires, throttle cable, etc. Running about half throttle yesterday when it started to lose rpm's. It would only run at about 30% of power when wide open and went through a
bunch of gas in 10 minutes. I did spray some carb cleaner but it did not change anything. Both carbs. are spraying a
lot of gas out the throat...my guess is it is electrical...coil, trigger, etc. and not all gas is firing in cylinders.

I know just enough to be dangerous........any thoughts/advice, other than heading to repair $hop. Thanks.

as of today......good spark both cylinders, took off bottom carb. since it is spraying the gas. cleaned carb
and float and needle look good as did rest of carb. back together and no change...blowing gas on bottom carb and running basically on top cylinder.....any thoughts??
 
Last edited:

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 1971 50hp johnson....need advice

First thing is to check your compression. If that is okay get an open air gap spark tester set at 7/16" and check the spark on both cylinders.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,216
Re: 1971 50hp johnson....need advice

Agreed 100%. But don't ignore the simple stuff----spark plug??? It's so easy to assume the worst.
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,129
Re: 1971 50hp johnson....need advice

Check your fuel bulb holds firm with fuel with the engine off. Ive seen carb floats fail and the motor starts chewing through fuel and running over rich and thus you lose a lot of power
 

pn

Petty Officer 1st Class
Joined
Apr 20, 2013
Messages
374
Re: 1971 50hp johnson....need advice

check fuel pump too.
 
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