fuel pump pressure

[mike58]

I have 1983 200 hp don`t know the serial # and motor starts right up idles fine and revs up fine on land but bogs out in water upon accelaration. Changed 2 coils and have a nice blue spark on all cylinders checked the fuel pump pressure and have 1.5 pounds at idle book calls for 2.5 at idle and up to 6.5 when you give it throtle do you think that could be the problem?(rebuilt the carbs this summer and it worked fine)put fuel in a aux. tank and still bogs.any input would be most helpful (ps rebuilt both fuel pumps this summer could the check ball go bad?) thanks Mike

 

[ezeke]

Re: fuel pump pressure

It is much more likely that you are dropping a cylinder or two and that it is noticeable only under load. Pull the spark plug wires one at a time to isolate the cylinder that is[are] not performing. Then do a compression test. ​

If the fuel pump pressure is not up to specifications, you must determine that there is nothing on the tank, or supply side that is reducing the pressure. In other words, it is best to check the pump with a different tank and line.

BTW, make sure that the coil grounding is absolutely clean, and that you have not switched the coil wires.​

 

[mike58]

Re: fuel pump pressure

I already pulled each plug wire one at a time and knocks the cylinder out.comp. all good between 95-100 all cylinders and I tried an aux tank and same problem! (thanks for the reply)

 

[ezeke]

Re: fuel pump pressure

If you are certain that there are no leaks in your fuel system, then, if the pressure is being read below the second pump, per the manual, you may want to continue with the manuals instuctions re: swapping the pumps with replacements one at a time.​

Remember that any fuel pump only lifts fuel to the carburetor bowls and fills them until the floats lift closing the valve. The fuel pump does not pump fuel through the carburetors, that is done by the pistons.​