I cleaned and rebuilt the carbs, including removing the idle needle valves for cleaning. I set the float level according to the Mercury shop manual (1/4 inch above the bowl base on the carb housing).
I have been trying to adjust the idle valve with no luck - I have been trying with dog ears, not in water, I see I need to do that. (I also found a post that gives some detail about how to go about it - copied below).
But I have a couple questions.
At what RPM should the motor be running as I do these adjustments?
The Mercury manual says to start 2 turns out from seated, I have read a number of posts here that talk about 1.5 turns - are either as good as the other?
I reused the old idlen needle valves - I used Sierra kits and the replacment valves were different shape (with a shoulder before the tapered point) than the originals. Tthe originals looked fine; if I have not luck with adjustments under load, should I try the Sierra valves?
The problem I had that lead to the carb cleaning was that the engine would not run up to speed, then eventually died and would not start. This happened when hooked up to the built-in fuel tank and a spare 6 gal tank with fresh fuel mix, so I don't think it is a fuel line issue. I had rebuilt the gas pump 2 or 3 years ago so I assumed it was not that.
FYI this is a 1986, 4 cylinder, 45 HP with exhuast through the leg, and 2 carbs.
The post I found re: adjustments is as follows: any other advise would be apprieciated.
"Idle mixture begins at one and one-half turns out from LIGHTLY seated. This should give enough fuel to get the motor started and in gear. Idle mixture MUST BE perfected ON THE WATER and IN GEAR, this provided the proper exhaust back-pressure and load on the motor.
Once warmed up and IN Forward gear ON the water, adjust each idle mixture screw to 'Best Idle Speed'. Taking time between each small adjustment to allow the motor to burn off any excess fuel. Make VERY SMALL adjustments, just the width of the screwdriver blade slot.
Once adjusted to 'Best Idle' the motor needs even more idle fuel to provide the additional fuel necessary for acceleration. Turn each mixture screw out twice the width of the slot, test acceleration, ANY bog, lean cough, hesitation, is proof the motor needs even more idle fuel. Open each just another blade slot width and retest acceleration.
Repeat to perfection.
Note; A heavier loaded boat may need additional idle fuel for acceleration, a full fuel tank(s), full coolers, added passengers, all add to the load on the motor and may require another slight tweek of the idle fuel."
I have been trying to adjust the idle valve with no luck - I have been trying with dog ears, not in water, I see I need to do that. (I also found a post that gives some detail about how to go about it - copied below).
But I have a couple questions.
At what RPM should the motor be running as I do these adjustments?
The Mercury manual says to start 2 turns out from seated, I have read a number of posts here that talk about 1.5 turns - are either as good as the other?
I reused the old idlen needle valves - I used Sierra kits and the replacment valves were different shape (with a shoulder before the tapered point) than the originals. Tthe originals looked fine; if I have not luck with adjustments under load, should I try the Sierra valves?
The problem I had that lead to the carb cleaning was that the engine would not run up to speed, then eventually died and would not start. This happened when hooked up to the built-in fuel tank and a spare 6 gal tank with fresh fuel mix, so I don't think it is a fuel line issue. I had rebuilt the gas pump 2 or 3 years ago so I assumed it was not that.
FYI this is a 1986, 4 cylinder, 45 HP with exhuast through the leg, and 2 carbs.
The post I found re: adjustments is as follows: any other advise would be apprieciated.
"Idle mixture begins at one and one-half turns out from LIGHTLY seated. This should give enough fuel to get the motor started and in gear. Idle mixture MUST BE perfected ON THE WATER and IN GEAR, this provided the proper exhaust back-pressure and load on the motor.
Once warmed up and IN Forward gear ON the water, adjust each idle mixture screw to 'Best Idle Speed'. Taking time between each small adjustment to allow the motor to burn off any excess fuel. Make VERY SMALL adjustments, just the width of the screwdriver blade slot.
Once adjusted to 'Best Idle' the motor needs even more idle fuel to provide the additional fuel necessary for acceleration. Turn each mixture screw out twice the width of the slot, test acceleration, ANY bog, lean cough, hesitation, is proof the motor needs even more idle fuel. Open each just another blade slot width and retest acceleration.
Repeat to perfection.
Note; A heavier loaded boat may need additional idle fuel for acceleration, a full fuel tank(s), full coolers, added passengers, all add to the load on the motor and may require another slight tweek of the idle fuel."
