40 Hp Johnson outboard motors stalls out after a few minutes running then takes forever to start again

https://www.google.com/search?q=1957+johnson+outboard+10+hp+fuel+oil+ratio

What is the mix ratio for a Johnson outboard motor?

Any Johnson outboard motor built since 1964 requires a 50/1 fuel ratio. Motors built prior to that date require a 32/1 ratio, with the exception of a few fishing motors built prior to 1955 that use a 16/1 ratio.

Feb. 22, 2021

What is the mixing ratio for a Johnson outboard motor? - Mvorganizing.org

Has this engine been sitting for a while?? Sounds like the carbs need cleaning and setting... a job for a professional!! A professional motorcycle mechanic can do this also!!

1988

Little Johnson outboards are famous for being very easy to start, So- first pump up the gas, then set the throttle open to the neutral stop -pull thru once -then set the choke to fully closed (look down the carb and see if it is) and pull thru 2 more times- open the choke. try again --If it is not running by now you have a bad ignition, or the engine has no compression. - very likely if you are running the wrong spark plugs. You may have some shattered reed valves.

See if the spark plugs are getting wet with fuel.

Take the cowling off. Also drop the foot. There wil be a stainless linkage rod that runs the length of the motor that you will have undo to drop the foot. The water impeller will be inside a stainless casing that you will have to disassemble.

go to an auto parts store and get a can of gasoline additive called seafoam. Read the label so you know how much to add to your 6 gallon tank. This stuff works wonders on outboard motors.

Not familiar with that specific motor but had similar vintage smaller HP Johnsons. From my experience it sounds like it could be that the high speed carb adjustment is too lean. What I would try is running the backing off the high speed screw 1/4 turn to 3/4 turn, then test. If works better, screw back in in 1/8 turn increments until the problem recurs, then back out 1/4 turn and leave it there.

Ihave a 1991 70 hp Johnson outboard thats hard to start the first time but starts good after that. Seems to be flooded. Starting rpm seems to be low.

Hey BK, Its still the carburetor!.... take it to a qualified professional.. there are TOO many tiny passages and jets that must be perfectly clean for a small engine to run properly..