Johnson 70 hp different carbs

[53150]

I've run into another problem with my Johnson 70 hp. The #1and #2 carbs have low intermidiate and high speed circuits. Thee #3 carb just has high and low circuits. The #3 cylinder is not firing right. When looking into the front of the #3 carb. the fuel is coming out in big drops instead of being atomized. The top two carbs have a small tube running up though the throttle body and the #3 doesn't. Any ideas What might be going on?<br /><br /> Thanks <br /> Will Vaughan

 

[Hooty]

Re: Johnson 70 hp different carbs

What year Johnson?<br /><br />c/6<br /><br />Hooty

 

[53150]

Re: Johnson 70 hp different carbs

My engine is a 1980 mdl. I just cleaned and rebuilt the carbs. ,but the problem persist that's what leads me to question the third carb. difference.<br /><br /> Thanks <br /> Will Vaughan

 

[53150]

Re: Johnson 70 hp different carbs

A little more info. The third cylinder is getting too much fuel. Every time I try anything and pull the plug back out to check it it is very wet with fuel. The cylinder has very good spark. and good compression (125psi). The engine will Idle but not very smooth and goes dead when I try to put it into gear. Will not reach full throttle when I do get it to stay cranked in gear.<br /><br /> Thanks <br /> Will Vaughan

 

[Hooty]

Re: Johnson 70 hp different carbs

The upper and lower carburetors, on your engine should be the same. The different one should be the middle one. After getting that streightened out, you probably need to do a link & sync.<br /><br />g'luck & c/6<br /><br />Hooty

 

[53150]

Re: Johnson 70 hp different carbs

Thanks for the help, but I want to make sure I get it right. The #1and #3 carbs should have the intermediate ciircuit and the #2 should not. Would the present set up cause the #3 carb. not to atomize fuel properly, or will that be another problem?<br /><br />Thanks <br />Will Vaughan

 

[Hooty]

Re: Johnson 70 hp different carbs

Look here <br /><br />c/6<br /><br />Hooty

 

[53150]

Re: Johnson 70 hp different carbs

That breakdown was showing the center carb. That is the one on #2 on my motor. The #1 is the same type of carb but with the different linkage for the top carb position. The #3 is a differnt type of carb. it doesn't have the jet in the upper left side(intermidiate circuit) like the other two. It looks like from that breakdown that the upper and lower carbs should be exactly the same (same part#). Is it likely that this mixmatch is causing my problem?

 

[ob]

Re: Johnson 70 hp different carbs

Will,the carb that was misplaced may have a sticky float valve causing it to flood.Iwould remove it and take off the carb bowl and clean and adjust the float.When you initially pump the primer bulb ,does it get firm and hold ,or can you keep squeezing fuel through to the carbs?

 

[53150]

Re: Johnson 70 hp different carbs

The primer bulb gets firm and holds. I just thoroughly cleaned and rebuilt all three carbs. Replaced needle, seat, float and all gaskets. I've since taken the carbs back off and am soaking them in carb. cleaner. Maybe I didn't get them clean enough, but I sure thought I did.