25hp Johnson stalls when I throttle up

[matt198325]

I just bought a new boat a couple weeks ago and it came with a 25hp Johnson model number cj25rwlk. At first I couldn't get it to start but a quick replacement of the plugs fixed that, starts every pull. The problem now is then when I try to give it any throttle it stalls out. It will run on high throttle when I first start it but if I go back down to an idle and try to accelerate again it will stall every time. I removed the carb and cleaned it out and it looked fine and the fuel line is brand new. Any ideas on how I can fix this and get out fishing.

 

[HighTrim]

Re: 25hp Johnson stalls when I throttle up

The most likely issue is still the carbs. Did you remove the jets/orifices and thoroughally clean them?

Also check to see if the timer base (starboard side, under the edge of the flywheel, linked to the throttle lever) moves smoothly without sticking when you advance the throttle.

Take the airbox cover off & observe whether the throttle plates are parallel.

Also, the timer base should start it's travel *before* the throttle plates start to open, else she'll fall flat when you try to accelerate.

 

[Okee Jimmy]

Re: 25hp Johnson stalls when I throttle up

I couldn't cross over that model number, is it a tracker? If your carburetor has a low speed mixture screw, I'd try richening up the low speed mixture. It sounds to me like it is having trouble making the transition between the low and high speed circuits. Also, did you replace the round gasket on the main fuel nozzle when you cleaned the carb? If this is torn, or left out you won't be able to properly adjust the motor, and it will do all kinds of strange things.

 

[matt198325]

Re: 25hp Johnson stalls when I throttle up

I am not sure about the low speed mixture screw. The only adjustment I can see is a black knob on top of the carb which I believe is the fuel/air mixture adjustment, I have played around with this but it hasn't made a difference in fixing the problem. As for the round gasket, I made a new one out of gasket material that is the same size, so it is replaced. I have read some posts that about a possibe fuel pump problem but I am not sure how to check this or adjust it.

 

[Okee Jimmy]

Re: 25hp Johnson stalls when I throttle up

I would go to my local Evinrude dealer and get the factory nozzle gasket. This is made out of an alcohol resistant rubber, and is designed to be self centering while still allowing fuel flow. I can't tell you how many times I've come across a leaky nozzle gasket causing funky carb. problems.

0332708 nozzle gasket $3.05

 

[Kettler]

Re: 25hp Johnson stalls when I throttle up

I just went through a similar problem see the post "engine stalls when throttle is advanced" but first buy a carb kit and really clean the carb and make sure the float is properly adjusted.

Do you smell gas when it stalls?


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