Fuel Pump ? 1973 85hp

[snwwlkr]

1973 Chrysler 85hp outboard..

This might be one of those dumb questions.

Does the fuel pump have to be functioning properly for the motor to run properly? Meaning, as long as the bulb on the fuel line is pumped up tight does the fuel still have to be additionally pumped by the factory pump on the side of the motor? I do have a clear inline filter and can also see what looks like plenty of fuel in it.

Basically I'm fighting a situation where the motor starts and runs and then after warming up for a minute it will either die almost instantly or loose power and die over a 3-5 second period. I've done numerous electrical checks and am really having a hard time zeroing in on the issue. I've changed several parts like CDI and coil with extras I had with no change. Then changed the ignition and thought the problem was solved only for it to start dying again. It may be multiple issues possibly ignition and fuel pump?

 

[Frank Acampora]

Re: Fuel Pump ? 1973 85hp

I'm not sure I understand exactly what your question is.

It doesn't matter how the carb bowl gets filled, as long as it stays filled while running. The primer bulb forces fuel through the fuel pump and through the check valves there The float maintains the proper fuel level by either dropping to open the inlet needle or rising to shut it .SO: If you elect to pump the primer bulb constantly, the engine will run even without a fuel pump.

However, without pumping the priming buln, then yes, the fuel pump MUST function correctly for the engine to run well.

Yes, you may have multiple problems. It would be a good thing to remove the carbs and clean them. Also, as a matter of course, replace the fuel pump diaphragm and gasket

 

[snwwlkr]

Re: Fuel Pump ? 1973 85hp

I guess to clarify. I wasn't sure if for some reason the carbs required greater pressure than that supplied by just the fuel bulb. So basically you answered my question about that.

I do of course understand that for continued running without pumping the bulb requires a fuel pump.

That said I've learned my way around this Chrysler motor fairly well over the past few years to not be a total gear head but now have some intermittent problem that is driving me CRAZY!! More to learn no doubt.

I'll keep hacking away at it..

 

[jerryjerry05]

Re: Fuel Pump ? 1973 85hp

First a compression test .
Take the pump apart.Check for any holes/tears or a streched diaphram.
Any inline connectors? They can leak and suck air.
The compression makes the pump work.
Ethanol? It makes the older hoses soft mushy and collapse.

 

[foodfisher]

Re: Fuel Pump ? 1973 85hp

If the bulb collapses prior to dying, you have a fuel tank vent/pickup tube obstruction. Throw some more symptoms at us.