Carb- how to lean/rich adj. knobs?

[aeviaanah]

Just got this 1962 15hp sea king running. This was my first rebuild and it's runnin sweet just curious if I'm adjusting lean/rich knobs properly.

I read manual for initial knob setting 3/4 turn out from fully seated. At this setting it would pop every few seconds, I backed it off until I got the pop to stop. What else should I look for when fine tuning both the low speed and high speed knobs?

 

[roadkill636]

the low speed is ONLY adjusted at an idle, in newtral,, the high speed must be adjusted when running ON THE WATER IN GEAR at full speed under a load. dont do it in a bucket or hose, only while at full speed moving across the water for best results, its hard to do but thats where it is made to be adjusted at

 

[cajuncook1]

(Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)

Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.

Setting the high and low needle valves properly:

NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle va /lve adjustment.

(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, wating for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.

(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

 

[Pappy]

Since that engine is prior to 1963 see if the fuel mixture labels are still intact on it. I believe that engine will still need to be run on 24:1 fuel mix. If not legible then I would definitely run it at that ratio just to make sure your classic will stay together and give you a full service life.

 

[aeviaanah]

(Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)

Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.

Setting the high and low needle valves properly:

NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle va /lve adjustment.

(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, wating for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.

(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

Thanks for the tips, that is pretty much along the lines of what I did. Just listened to the engine for a nice idle.

Since that engine is prior to 1963 see if the fuel mixture labels are still intact on it. I believe that engine will still need to be run on 24:1 fuel mix. If not legible then I would definitely run it at that ratio just to make sure your classic will stay together and give you a full service life.

This engine is 24:1 fuel mix. The sticker is missing but I found a service manual. Thanks!

the low speed is ONLY adjusted at an idle, in newtral,, the high speed must be adjusted when running ON THE WATER IN GEAR at full speed under a load. dont do it in a bucket or hose, only while at full speed moving across the water for best results, its hard to do but thats where it is made to be adjusted at

Ill be sure not to adjust high knob until i am on the water and moving full speed. I got the low knob adjusted pretty good. Thankyou!