1996 mercury force 120 hp carb problem

[ekincaid86]

I have a 1996 mercury force 120 hp i have changed to the correct jet for elevation .92 i have changed both needle valves set the floats replaced bad reeds and no matter what i do the bottom carburetor spits gas out the top vent only does it when i give it full throttle and it gets higher rpms and floods it dont know what else to do any suggestions?

 

[jerryjerry05]

Welcome.
​Do a compression test.
Probably not a problem but all info will help.
Before you rebuilt the carbs did the bottom give you a problem?

Still have the old parts?
Replace the needle with the old.
Pics of the old and new needle??
Do both needles have rubber tips?
Or are they solid tips?

Since your new you probably can't post pics yet.
I think you need to post 5 times to add pics.
You can send me your e-mail in a PM and I'll get the pics that way.

 

[ekincaid86]

Yeah it was doing the same thing thats what made me think the needle valve was bad in the first place. It has a rubber tip on it. I threw away the old one ordered another new one the other day just in case something was wrong with this new one. Compression was good all cylinders were around 140 we took each plug out grounded it to motor and checked for spark all had spark. I start my rotation at work tonight gonna change out new parts this coming monday my email is ekincaid86@hotmail.com if u want to send me an email so i will have urs i will email you pics of inside the carb when i take it apart i also ordered a new float and float pin just in case and going to rebuild fuel pump

 

[pnwboat]

From what you describe, either the float level is set too high, or there is some debris caught between the end of the needle valve and seat. Most likely the float setting since it only does it at WOT where fuel flow/pressure is the highest

I've had to play around with the float level from time to time with the needle valves in the kits that are available these days. I suspect that the needle valve is a bit off as far as the factory specs so the factory float setting doesn't quite work. Try setting the float level so that the free end of the float is about 1/32" - 1/16" further away from the carb body than factory specs.

 

[ekincaid86]

Ok i will try that monday and let you know how it goes thanks for the help

 

[ekincaid86]

Ok put new parts on the fuel pump and bottom carb. That fixed the problem with the bottom carb overflowing but now that carbs are running out of gas starting at 4000 rpms how much gas should be in the bowl i may have them set too low