Home › Forum › Ask A Member › Stalling 1965 Merc 39 › Re: Stalling 1965 Merc 39
That sounds like a fuel problem. There are a couple of quick and easy tests you can run: when the motor starts to slow down, squeeze the primer bulb to bypass the fuel pump. Also, try removing the fuel tank cap; if the vent hole under the knob is blocked, the motor will run OK with the cap off.
Third (and I ran into this myself) be sure the line from the motor side fitting to the fuel pump is clean, and take the fuel pump apart and clean it carefully. Tiny bits of dirt can get under the valve discs. Use a magnifying glass to check.
The diaphragm shouldn’t be affected by operating temperature but if it is cracked, holed or torn, replace it. (I have had very good service from Ferguson-Poole Inc.)
Look into the tank. If there is a lot of debris, it is possible that the fuel intake inside the tank is clogged.
Your little Merc should give you a lot of good service. They’re not known as problem motors and they’re not difficult to repair. Of course, there is a vast amount of knowledge in this Club and it is generously shared. Don’t give up on the Merc.