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This adjustment should result in a true approximate setting. 3 adjust one carburetor at a time.
Optional outboard mounting kits shown must be used if outboard will not be permanently fastened to the transom with mounting bolts.
How to adjust mercury outboard carburetors. The parameters for adjusting the carburetor on a Mercury outboard involve both the idle speed screw that controls the motors speed at idle and the mixture screw that controls the fuel-to-air ratio. Adjusting both of these requires that you have the motor running. How to Adjust the Carburetor on a 40-HP Mercury 2-Stroke Outboard by Will Charpentier in Health The parameters for adjusting the carburettor on a Mercury outboard involve both the idle speed screw that controls the motors speed at idle and the mixture screw that controls the fuel-to-air ratio.
Continue to turn the idle mixture screw clockwise until the mixture becomes lean and the outboard motor begins to misfire youll notice the rpms falling. Then set the outboard idle mixture screw 14 turn out counter clockwise from the lean out position. This adjustment should result in a true approximate setting.
HiCustomer With an engine of this age I would not think that adjusting the air mixture screw is the answer as the indication is there of another problem my advice on this engine would be to take the carb off and clean it I suspect you have debris contaminating the idle circuit which will need to manually be removedno 10 in the diagramI Also dont think the idle screw is able to be adjusted as mercury have. The idle adjustment is on the underside of an outboard carburetor. Use a small adjustable wrench or screwdriver and rotate the idle adjustment 14 turn clockwise until the engine idle slows.
Rotate the valve counterclockwise in 18-turn increments until the engine idles smoothly. Subscribe On todays video I show the carburetor removal procedure for 2 stroke Mercury outboards. I also go over the tools needed and show step by step.
Turn both screws back counterclockwise 1-14 turns to set the starting position for the adjustment on the 2-cycle outboard motor. Start the motor and let it warm up for about five minutes. Remove the rubber vacuum hose from the vacuum port and attach a vacuum gauge to the port.
Increase performance through airflow intake. The engine sucks in air and blows air out. If this process is hindered then performance is lost.
Examine the air intake on the engine. Look for obstructions debris or other dirt that may clog the engine. Clean the air intake thoroughly.
Examine the air filter and replace if it is dirty or damaged. I have a 35hp Mercury outboard sn A151937. After rebuilding carb needle valve doesnt appear to be sealing off fuel supply fuel being pushed through vent hole when priming.
I installed a new float old one had gas in it. My question is can any of you guys tell me what controls the float level and how to adjust it. Insert a screwdriver into the Mercurys idle adjustment screw located at the bottom of the carburetor and turn it to the left until the motor barely continues to run.
Insert the screwdriver into the valve screw and turn it in 18-turn increments to the right until the motor idles evenly and smooth. If you are upgrading a 4hp Mercury to a 6hp we recommend our 4hp to 6hp Upgrade Kit that includes both this carburetor and the correct propeller to use in order to take advantage of the additional power. If you are upgrading a 5hp Mercury to a 6hp this carburetor is all you will need as the 5hp comes with the higher pitch propeller already.
Locate the upper carburetors lever adjustment screw on each carburetor and loosen it. Rotate all the throttle shafts a bit permitting them to snap shut. Push upward gently on the adjustment tab found on the bottom of the throttle cam where the throttle shaft connects to it to prevent its movement.
Mercury 98Hp Carburetor setting I forgot to replyHere is what happened when i tried to adjust idle screw. I tried doing setting as per above instructionBut some time motor startedeven if it started it starts in full rpmwhen i lower it to near idle it stopsBut some time i. It is best to adjust the carburetor while your boar is in the water.
Loosen idle screws counter clock wise or from a lightly seated position 1 to 1 14 out. Start up engine and ensure the engine is idling properly not backfiring warmed up. If it is not correct you may have to adjust the idle.
Optional outboard mounting kits shown must be used if outboard will not be permanently fastened to the transom with mounting bolts. A a - Outboard Mounting Kit Part No. Center outboard on the transom.
Install the outboard so that the anti-ventilation plate is in line or within 1 in. 25 mm below the bottom of the boat. So if you need to adjust them relative to each other you need to loosen that sensor linkage first get them both where you want them then lock off that Center linkage.
All right what Im going to do now is set the mixture screws to the factory setting for these which is basically two and a half turns out. Mercury Mariner carburetor rebuild kits and repair manuals. Rebuild Mariner carburetors remove Mercury outboard carburetors adjust Mariner carburetors set the idle on Mercury outboards install Mariner carburetor floats adjust the fuel mixture on Mercury outboards remove linkage from Mariner carburetors.
How to clean out and rebuild your carburetor on an outboard engine. The whole process is not hard just tedous. It takes patience and a clean work environmen.
The idle adjustment is on the underside of an outboard carburetor. Use a small adjustable wrench or screwdriver and rotate the idle adjustment 14 turn clockwise until the engine idle slows. Rotate the valve counterclockwise in 18-turn increments until the engine idles smoothly.
Mercury outboard motor float problem how to adjust float on 2002 99 hp. Ser 0T487689 - Answered by a verified Marine Mechanic. We soak all outboard carburetors with Outboard Engine Decarbon Chemical which wont hurt anything inside the carberator.
And then wash off with soap and water and complete with drying off with compressed air. 120 Force Outboard carburetor question s Just to show Im not crazy here is a screen shot of a similar image to the one found in my owners manual. 1 Start engine until fully warmed up.
2 Return control level to neutral position. 3 adjust one carburetor at a time.