1987 35 hp not running right

[Spindle]

I have a 1987 35 hp Mercury motor that is driving me NUTS!!! It keeps going dead at slow speed. After it sits for about 15 minutes I have to repump the fuel line bulb to get it started. When it goes dead while moving at slow speeds I have to repump the bulb again and then it starts right up. The bulb is semi hard at that time It runs great at high speed. I have ran it on two different fuel tanks, replaced all the hoses from the tank to the carb, had the carb professionally cleaned and rebuilt, put in new spark plugs, had the compression checked and both cylinders have 130 lbs of compression. The Marine mechanic that rebuilt the carb said the fuel pump is good because it runs so well at high speeds. Any ideas ? Thanks

 

[oldman570]

Re: 1987 35 hp not running right

Replace th fuel line between the fuel pump an carb with clear gas line and watch for air bubles and the fuel flow. From what you have stated it still could be a bad pump that the valves are leaking by at slow RPM's. If it will not restart after dieing right away you may be haveing electrical troubles. Switchboxes, stators, and triggers can heat up and need to cool down and work again. Checking the spark right away when it happens will rule them out or not. Has the water pump been replaced in the last 3 years? It might cause a overheat problem that effects the whole works. Just my Thoughts.
Oldman570