Johnson 3 hp won't run

[RBib]

Hi everyone, I just took possession of a 1963 Johnson 3 hp OB. The motor, while it appears to be in almost pristine condition otherwise, sat unused for a number of years and won't start. I've replaced the plugs, drained and cleaned the fuel tank, put in fresh mix. I sprayed some fuel mix into the combustion chambers and she showed a brief signs of life which leads me to believe the carb is gummed up etc. How hard is it to remove and clean and/or rebuild the carb on these small engines? Do I need to get a shop manual? I'm fairly mechanical but have never messed with small OB carbs. Thanks, Ralph

 

[bktheking]

Re: Johnson 3 hp won't run

Carb is one thing but what about eveything under the flywheel, coils crack from sitting. To remove the carb is a fuel line and a couple of nuts, then clean the carb and blow it out with compressed air, replace parts that come in a kit, not that difficult.

 

[RBib]

Re: Johnson 3 hp won't run

I haven't check compression with guages but I believe it is is okay as it feels fine when pulling the starter rope. Not sure if that is a reliable indicator or not.
As I stated in my original post when I sprayed fuel into the cylinders it fired immediatley although very briefly leading me to believe that the ignition and compresiion are okay??

 

[tx1961whaler]

Re: Johnson 3 hp won't run

I will run just fine on only one cylinder. Check the spark on both.
You didn't post the motor year or model #. Make sure the fuel valve and cap vent are open and gas is getting to the carb

 

[pman7]

Re: Johnson 3 hp won't run

I will run just fine on only one cylinder. Check the spark on both.

Just curious here, at what horsepower do they go to 2 cylinders? I know the 2hp is just 1.

 

[F_R]

Re: Johnson 3 hp won't run

The 3hp is a twin. Once upon a time, Johnson made a 2.5hp twin.