Mercury classic 50 (45hp) won’t stay running

[Jd0g]

Hello, I was wondering if anyone has any insights or suggestions. I’m trying to figure out why this motor won’t stay running, it seems to be a fuel problem. The motor won’t stay running unless it is primed consistently. The fuel tank pick up is clean and the hose and bulb are brand new. I rebuilt the fuel pump with a genuine mercury kit and tested it by cranking the engine it seems to be pulsing adequately because it spits out fuel. The fuel filter is clean and all the fuel lines connecting to the carbs. As far as I’m concerned the carbs should be getting fuel. I also inspected all the jets and gaskets on both carbs and they are all clean. The needle and spring seem to be in working order. Could the floats be possibly causing an issue if they are not sitting at proper height? When the motor is running it sounds good and revs nice. One other thing I noticed is that the water jacket gasket needs to be replaced, water does drip by the spark plug holes but I’m not sure if that would be causing a fuel issue. Any insights would be appreciated thanks

 

[BrianVT]

The floats seem like a good thing to check. Make sure that they are level with the carb. body seam when the carb. is turned upside down and make sure that they still float (old ones do go bad).
I would also check that your float needles are making a good seal. With the float and needle raised you should not be able to blow through the fuel supply hose.

 

[Jd0g]

The floats seem like a good thing to check. Make sure that they are level with the carb. body seam when the carb. is turned upside down and make sure that they still float (old ones do go bad).
I would also check that your float needles are making a good seal. With the float and needle raised you should not be able to blow through the fuel supply hose.

Thanks I will check that, I actually pulled off the carbs and the float level seems to be very off on one of the carbs. I also noticed that the idle mixture screw was all the way seated (clockwise) on the lower carb and only 3/4 out on the upper carb I believe they are suppose to be at least 1 full turn out hopefully this will resolve the issue I will be putting them back in later today and testing.

 

[Jd0g]

motor is now running good seemed to be that idle mixture screw, i also adjusted the float. if anyone is having similar issues as i was i would definitely check those things. was kinda weird that the person i bought it from had that mixture screw all the way in cutting off fuel flow