1980 70hp Johnson top carb spitting fuel at idle

[ddzurik]

I bought a boat that sat for six years. When I finally got it started it had no power at WOT and bogged bad.
I replaced every electrical component on the engine, stator, timer base, brain box, rectifier and coils. Timing is at 20 btdc.
I also boiled out and rebuilt all 3 carbs. The engine starts great and runs good but the top carb at idle seams
to spit little droplets of fuel out the back of the carb. When revving the motor I don't see anything abnormal.
after awhile at idle it seems like it drips a little gas from the back of the carb. I have torn it down 3 times
and I am sure the new needle valve is closing tight. When held upside over I can not blow air into it.
the carb is spotless. Float is level inverted and 1" of float drop right side up.
All three cylinders have 125 psi of compression. The reed valves look clean. Any suggestions.
Thanks for any input.
Dave

 

[kodibass]

Re: 1980 70hp Johnson top carb spitting fuel at idle

When you say the reed valves look clean, So did you pull the intake cover and check them? I'm not that up on the 70's but spitting thru the carb is a symptom of a reed problem, but not to sure about the back of the carb? Swap carb with lower and see if problem follows, check intake/carb gaskets, and look over fuel/vac lines. I had a 35 doing similar and it was a cracked nipple at base of carb body. best of luck finding the problem.