johnson running problem

[delguy]

Thanks to anyone that can help. I will give as much info as I can.
I have a 1994 johnson outboard. 25hp. j25rerc
the problem is that the engine surges or sputters when trying to get on a plane.

have cleaned and rebuilt carb
changed plugs..both were equally dirty(oil,carbon)
changed fuel pump diaphram
changed fuel pump screen
compression 118,120
spark is good on both

This engine has a primer for cold start. pull it twice and it kicks right over. At idle plunger has to be pushed or it wont idle well. but when inreasing rpm it starts to spit and sputter. If you pull the plunger out a bit it smooths up and doesn't sputter as bad if at all. Not sure what else to check unless the primer assembly is bad. please help!!

 

[Daviet]

Re: johnson running problem

By the way you are using the primer it sounds like a fuel problem. When you cleaned the carb did you remove the all the jets, clean and blow out with compressed air? Make sure all of the passages were blown out also. The high speed jet is in the bottom of the carb and is the first to clog up.

 

[delguy]

Re: johnson running problem

When I cleaned the carb, I removed the idle screw and spring, the float, spring and needle. I also removed the gas inlet and jet(assume its the high speed). Completly cleaned, then blew out all passages with air. The primer is what I suspect it is but not 100% sure. I was also thinking of replacing the lines, even though they look o.k.