My Johnson 120 won’t rev in water

[Dirtyrider]

The rpms will go to 5000 with muffs out of the water but will not go above 2000 in the water it happened out of the blue on the water and we had to go back to the dock at about 7 mph top speed at full throttle any ideas…?

 

[racerone]

Timer base not rotating ?-----Lost spark on 1 or 2 cylinders ?-----Overheating and S.L.O.W. kicking in ?-----So post actual compression values here.----Does spark jump a gap of 3/8" on each lead?----Water in the fuel ?

 

[Dirtyrider]

I have great spark on all 4 cylinders gaps are correct I changed fuel pump and plugs made no difference not sure on compression have not checked it yet, I am glad you mentioned water in the fuel because that’s what I was originally thinking but a “boat guy” said no way I am new to the boat world this is my second my first one never gave me any trouble I am going to check the fuel tomorrow thank you for your input hope it works

 

[racerone]

post #3 is a very long sentence.

 

[kevinj]

I have great spark on all 4 cylinders gaps are correct

What spark plugs are installed and do they jump a 3/8" gap using an air gap tester with all 4 plugs removed?

I changed fuel pump and plugs made no difference

That was a big leap to change the fuel pump before verifying everything else.

not sure on compression have not checked it yet

We need to know compression #'s and spark gap results before moving forward.

I am glad you mentioned water in the fuel because that’s what I was originally thinking but a “boat guy” said no way

Water in your fuel can cause all kinds of headaches. Using your primer bulb, pump fuel into a glass jar until full then let it set for 30+ minutes. If you get an off-color layer in the bottom of the jar then you definitely have water in the fuel.