1991 force 90 hp only runs on middle cylinder

J

JON MCMANUS

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May 20, 2019
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compression on the cylinders are between 100 and 105psi. carbs have been cleaned and i have spark in all 3 holes. the boat ran about 10 years ago and has been sitting since. I replaced one of the CDI boxes with no change help I am getting confused and frustrated lol/.
 
jerryjerry05

jerryjerry05

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outboardignitiondotcom has test procedures.
You can use a regular analog meter for the basic tests but will need
a DVA or Peak Reading Volt meter to get to the more technical tests.

But if you have spark??
Then you might want to clean the carbs?
Make sure the jets are clear.
A piece of dirt the size of a pin point can stop them from working.
Install a filter between the pump and the carbs.
G-2 G-3 G-12 Fram

The compression on all 3 is low but that could be the way you did the test or the gauge itself.
The good: all 3 are about the same :)
 
J

JON MCMANUS

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I have cleaned the carbs good but couldn't figure out how to get the needle valve out it is in the middle of the carb and i didnt want to damage it.
 
J

JON MCMANUS

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So I was also reading in my manual that all 3 carbs use different power jets. Was wondering if maybe this was my problem also
 
jerryjerry05

jerryjerry05

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What manual?
The main jets are all the same size.
They vary for the different elevations.

The air screw won't come out? Needle valve or float needle? Pics??

The only difference is the fuel inlet 2 are a T shape and the top is an L shape.
The bottom carb also has linkage differences, ie the roller for the throttle cam.
 
J

JON MCMANUS

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I downloaded one online and you are right all 3 are the same so. the idle jet straw is what i dont know how to remove but I dont think it is necessary.
 
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racerone

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Spray some fuel into the carburetors with motor running.----Report what happens on each cylinder.-----This may be as simple as a bad fuel pump diaphragm or wires crossed.
 
J

JON MCMANUS

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So it I replaced my stator and it started working going to go test out on the lake and see what happens hope I dont need to paddle lol.
 
jerryjerry05

jerryjerry05

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Shame on you!! Hijacking's a NO NO
But since you asked :)
I use a can of carb cleaner with the red straw, shoot the cleaner in the tip of the straw and see
if it shoots out the other end.

Cleaning a carb: the carb soaks can do more bad than good.
Some soaks can melt the plastic and the rubber in needle and seat.
Some seats have a rubber seal, SF and soaks can swell the rubber and make delivery a problem.
If your lucky the swelling will go down after setting dry 24hr.
 
The Force power

The Force power

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Feb 3, 2019
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jerryjerry05 said:
Shame on you!! Hijacking's a NO NO
But since you asked :)
I use a can of carb cleaner with the red straw, shoot the cleaner in the tip of the straw and see
if it shoots out the other end.

Cleaning a carb: the carb soaks can do more bad than good.
Some soaks can melt the plastic and the rubber in needle and seat.
Some seats have a rubber seal, SF and soaks can swell the rubber and make delivery a problem.
If your lucky the swelling will go down after setting dry 24hr.
Click to expand...

when spraying through, where is it supposed to come out? as that jet-straw goes into the top of the Carb.
 
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