Reply To: 1957 Sea King 12HP won't run right

[bayham3261]

I wouldn’t initially replace the float unless it is damaged. If it is cork you can reseal it. Generally speaking if you take the float bowl off and turn the carb upside down the float will rest in a fully closed position. This position dictates the height of the fuel in the float bowl. There should be a measurement you can find in a tune-up book that will indicate the distance between the float and the upper carb/bowl flange surface. To adjust the float height you carefully bend the needle valve tab with a pliers. Do not push down on the needle to bend. This is an adjustment that needs to be checked every time you clean a carb or replace a float. Brand new floats can be out of adjustment.

I don’t have a measurement for this carb float… maybe another member would know. Sometimes carb floats are designed to just be parallel with the carb bowl flange.

I’ve also heard about people installing floats upside down by mistake and having similar symptoms… goofy these things happen to the best of us!

If you’ve gone through the carb and everything is good, then look for cracks or poor fitting gaskets in the intake and block. A little light grease can seal cracks long enough to test. If the grease fixes your problem… you know where the issue is with an air leak.

If you have an air leak I wouldn’t expect that it would be at the crank unless it is worn out as mention previously. The old oil slinger style design on the crank top is generally looked as being reliable. I have heard that some other outboards rely on heavy oil mixes to provide a seal… theoretically if you were running a very light mix it could possibly occur on this type of motor as well.

A little information is a dangerous thing!