Mercury 50 hp 2 stroke carb adjustment


The parameters for adjusting the carburetor on a Mercury outboard involve both the idle speed screw that controls the motor's 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. While the adjustments seem minor, both affect the performance and economy of your motor. Move the motor's shifter into "Neutral.

Turn the idle speed screw until the throttle plate positioner does not touch the idle speed screw. The throttle plate will close. Loosen the jam nuts, located right below the throttle cam on the throttle cable. Move the the throttle to the idle position.

mercury 50 hp 2 stroke carb adjustment

Set the cam follower roller against the throttle cam. Tighten the jam nuts on the throttle cable and tighten the cam follower screw. Turn the idle speed screw clockwise -- to the right -- until there is a gap of between 0.

Attach a flushing attachment to a garden hose. Set the flushing attachment over the raw water intake ports of the motor and turn the hose on full force.

mercury 50 hp 2 stroke carb adjustment

Start the motor and warm it to its normal operating temperature range. Attach a shop tachometer to the motor's Number 1 cylinder. Turn the idle speed screw on the carburetor linkage to adjust the motor's speed to between and rpm. Put the motor in "Forward. Turn the screw counterclockwise one-quarter turn or until the motor no longer misfires.

With the motor in gear, "punch" the throttle for sudden acceleration and readjust the mixture screw if it "bogs down" before accelerating. Recheck and readjust the idle to between and rpm. Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.

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How to Adjust Idle Mixture Screws on a 2-Cycle Outboard Motor

FLOATS are not included in carb kits and need to be purchased separately if needed, but they rarely do need replacing. Revised: April 21 Right Here! Contact the Mastertech! Home Contact Us What's New! KIT KIT 8. KIT 3. WME, 22B, 23, 24, 26, 27, 28, 35, 43, 44, 45, 53, 68, WME, 22B, 23, 24, 26, 27, 28, 35, 43, 44, 45, 57, WME,23, 24, 26, 27, 28, 35, 43, 44, 45, 57, WME, 30, 314146, 47, 48, 49, 59, 60, 6162, 75, 76, 77, 7.

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ROUGH IDLE Mercury 50 Outboard 2 Stroke FIXED New Fuel Filter 2 Stroke Mercury 50 DIY 9M9XM00591C1

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mercury 50 hp 2 stroke carb adjustment

All Rights Reserved.Remember Me? Contact Us Advanced Search. Search Fishin. Results 1 to 10 of Thread: For you mechanic guys here For you mechanic guys here Long story short I hope. I have pro 17 with a 60 hp mercury. Last fall it began to spit a little but was not a continuous problem. This spring I've only been able to get out twice and so far both times full throttle out of gear no problem with engine. I checked the gas tank and have ethanol parts from the hoses in the tank and have now bypassed my main fuel tank and tried running of a small portable tank with clean fuel.

Tonight, ran motor with clean gas and carb cleaner and sprayed out carbs with cleaner but have not been back to test under load yet. I am a little leery of rebuilding the carbs since I dont consider myself much of a mechanic, but does any one else have any suggestions?

Sorry if this is not correct forum for this post. Thanks for any help gang. Re: For you mechanic guys here If so, have you tried adjusting them. You can do a google search on doing the adjustments for your specific motor. He can be reached at LWathen aol.

If you can't get your problem straighten out then give him a call.

mercury 50 hp 2 stroke carb adjustment

Originally Posted by ffitch Just make sure that the butterflies are opening at the same time. I had that issue once and it affected low end but I guess if it was bad enough it could affect the top end. I changed the plugs but it never seemed to help. Fuel quality is terrible now.

You need to treat each tank full. You have to do it at the end of the year, or this is what happens when it sets for to long.Routinely adjusting the idle mixture screws on a 2-cycle outboard motor will keep the engine running efficiently and provide power when you need.

Results for "websitesub:"Complete Carburetors""

The 2-cycle outboard motor has two idle adjustment screws on the top of the carburetor that can be adjusted with just a screwdriver and a vacuum gauge. You can fine-tune the idle mixture screws in a few minutes and keep the motor running strong. Turn the idle adjustment screws clockwise with a screwdriver until you feel a slight resistance without over-tightening the screws.

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. Adjust the idle stop screw on the side of the carburetor near the choke cable, turning the screw with a screwdriver until the vacuum gauge is reading about rpm.

Repeat Steps Four and Five for the idle air speed screw. Check the idle stop screw next to the choke and verify it is still running about rpm. Remove the vacuum gauge from the vacuum port, reattach the vacuum hose and shut off the 2-cycle outboard motor.

Carl Pruit has been a freelance writer sincespecializing in service journalism and travel. His work has appeared on various websites. Related How to Adjust a Roketa Carburetor. Related How to Tune a Snowmobile Carburetor.

Mercury Outboard Service Manuals Free Download PDF

Items you will need Screwdriver Vacuum gauge. About the Author.These idle mixture adjustment tuning procedures apply the Mercury outboards manufactured between thru —specifically HP to HP models. A downloadable version of the factory manual is available from this site. Procedures are applicable to the following models:.

Testing and diagnosis helps determine problems and possible causes. Its important to perform extensive testing and troubleshooting prior to any major tear down or repair work.

How to Adjust the Carburetor on a 40-HP Mercury 2-Stroke Outboard

This ensures that the full extent of the problem is understood beforehand and may prevent any unnecessary repair work. However, over time periodic adjustments will be necessary for optimum performance. When making adjustments to the carburetor, it may be necessary to adjust the carb settings while the motor is running in a test tank or out on the water. To accurately adjust the idle mixture and the idle rpm, the motor should be under normal operating conditions. Set the idle mixture screw at the specified number of turns open from a lightly seated position.

Turn the engine on and allow the motor to warm to normal operating temperatures. Without water circulating though the lower unit, the water pump will fail within in just 5 seconds. Furthermore, the engine risks overheating. Extensive damage will result. With the engine at normal operating conditions, place the engine in forward gear and turn the idle mixture screw counterclockwise slowly until the affected cylinders start to fire unevenly this is a result of an over-rich mixture.

This adjustment should result in a true approximate setting. A setting that is to lean will cause hard starting on a cold engine. In fact, the main reason for hard starting on a cold engine is a result of a lean setting.

Generally, its always better to have the setting a little rich rather than on the lean side. Always make sure the the engine is not running lean. If after the idle mixture adjustments are made and the motor hesitates during acceleration, the mixture is to lean.

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