1994 Johnson 50 hp Surging Problem

[djcvet]

I have a 1994 Johnson 50 hp 2 stroke engine that has just recently had both carbs cleaned and new kits installed by a competent mechanic. Other than running a little rough at idle, it has been operating satisfactorily. Last week while cruising on the lake, I noticed at around 3200 RPM the motor started to surge (drop from 3200 to 2200 rpm and then back up). Above 3200 rpm the motor ran fine. It was just at or around the 3200 rpm range where it wanted to surge. It almost acts like it starves for fuel for a brief moment. Any ideas?Also, I noticed that for the first time, when I pump the ball in the fuel line from the tank to the engine, it never would get solid (hard) like it always did before. Any ideas on that one?

 

[JUSTINTIME]

Re: 1994 Johnson 50 hp Surging Problem

sounds like bad fuel pump or dirty carbs

 

[bgbass.1]

Re: 1994 Johnson 50 hp Surging Problem

change the ball. when it does it did you try priming the bulb to see if it goes away if it does its fuel pump

 

[djcvet]

Re: 1994 Johnson 50 hp Surging Problem

It is definitely fuel related as we verified last night that the top carb is not getting any fuel. While I had the throttle all the way forward and the engine only running at half power we squirted gas directly in the carb intake and the power came up for a brief moment. We shut the motor off and pulled the little plug out of the bottom of the float bowl on the top carb when we got back in and and no gas came out at all. Questions -
1) What would cause this carbs float bowl not to have any fuel in it?
2) Why would it start and idle if this carb were not getting any or enough fuel?

 

[petryshyn]

Re: 1994 Johnson 50 hp Surging Problem

It is common to get debris blocking the needle and seat shortly after a carb service. It especially happens if you don't purge the lines before connecting them after a rebuild. Reclean both carbs and purge the fuel lines before reconnecting....When I say purge, simply stick the lines going to the carbs in a old water bottle and squeeze the primer bulb hard 10 times or so. Then inspect the fuel to see any debris.

Good luck