90 v4 carburator questions

[gulfcoastsurf]

1984 johnson 90 horse just did a rebuild on the carbs thanks iboats "great forum for now on i buy my parts here" runs great with the manual valve open red valve facing toward the water but you close it dies at idle but if your up on plane it will run fine with it closed and a little faster ? does it matter if i just leave it open?

 

[tashasdaddy]

Re: manual prime choke carb question 90 johnson 1984

Re: manual prime choke carb question 90 johnson 1984

means you did not get your carbs clean. the primer valve bypasses the carbs, and the fuel goes directly into the intake manifold.

turn the primer to auto, pushing in on the key activates it for cold starts, that is all it is to be used for. the manual setting is for rope starting, with a dead battery.

idle can not be set on muffs, and then expected to idle in the water, due to exhaust backpressure. idle must me set with the boat in the water, fine tuned so the the motor WILL IDLE IN GEAR.

 

[gulfcoastsurf]

Re: manual prime choke carb question 90 johnson 1984

Re: manual prime choke carb question 90 johnson 1984

how do you set the idle and also the little metel tubes that fuel flow up from int the carb bowl were slightly resting on the metal around not sitting straight in the middle

 

[tal]

Re: manual prime choke carb question 90 johnson 1984

Re: manual prime choke carb question 90 johnson 1984

I think those offset metal tubes are normal. I just did carbs on a 87 70hp and its 3 carbs were that way to. You need to make sure that little tube that's to the side is clean all the way up to the top of the carb. You can run a small copper wire from the bottom up to the top. Where it stops up there is your idle jet and chances are that little tube is plugged up. The jet all the way in the bottom behind the drain screw is your high speed jet, it needs to be completely open too. Make sure you float level is correct.

 

[gulfcoastsurf]

Re: manual prime choke carb question 90 johnson 1984

Re: manual prime choke carb question 90 johnson 1984

thanks makes me feel better that what was clog the high speed but i didn't get to take out the high speed jet on the bottom but soak it and spay it with air but how would it go about adjusting the carbs i thinking i would need that special screw driver

 

[gulfcoastsurf]

Re: carb question 90 johnson 1984

Re: carb question 90 johnson 1984

i got the service manual for the motor and notice the the top carburetor has a idle chamber on top of the carb and the bottom carburetor dose not have the idle chamber could this be a reason the motor will not idle and would that make the bottom carb harder to clean?

 

[Drum Luck]

Re: 90 v4 carburator questions

Sounds like you didn't get the idle circuits clean when you rebuilt the carbs. When you took the float bowls off there are two "plugs" on the bottom of each carb. They are about the size of a dime and two new ones come in each rebuild kit. If you didn't remove those then the idle circuits could have a lot of junk in them. You have to take a punch to them or use a small drill bit very carefully and then pry them out. I would check that first.

 

[gulfcoastsurf]

Re: 90 v4 carburator questions

sound like you might be right i try it and see what happens

 

[gulfcoastsurf]

Re: 90 v4 carburator questions

went and got the screw driver and removed all the jet high speeds low and intermediate and the were pretty gunk up and ran some strands of wire from an extension cord threw spray it with air and cleaner and it purrs like a kitten take it from me get the special screw drive or make one because that was the ticket to clean the carburetor jets and the price of a broken jet is about the same as the 20 dollars for the screw driver so get the real deal screw driver

thanks gcs