Nissan mfs6cul looses prime

[airboat86]

I have a new Nissan MFS6CUL 6hp outboard. I have to prime the motor before starting when it has not been running for a few hours. Is this normal? I had a Johnson 8hp Sailmaster for 25 years that would hold prime as long as the fuel line was connected. The Nissan has a 3 1/2inch diaphragm like object on the hose before the primer bulb. There is no mention of what the function is in the manual, and I wonder if has something to do with the loss of prime.

 

[pvanv]

Re: Nissan mfs6cul looses prime

It should start after a couple of hours, regardless of "prime" (because of remaining fuel in the carb), but maybe evaporation from the carb could affect that. The diaphragm thing is a fuel demand valve, required courtesy of EPA. It does affect quite a few things. You do need to run the carb dry at the end of the day (and you should then disconnect the fuel line at the motor), so then you will be re-priming anyway.

 

[Sea Rider]

Re: Nissan mfs6cul looses prime

In cold enrironments when stopping for some time, engine does cool fast, will need to advance throttle to start position, pull rope max twice, if doesn't start, pull choke, pull again, once started, inmediately close choke, set throttle to idle & let warm. If in heat environments with cold engine, place throttle to start position and pull rope, should start much faster...

Happy Boating

 

[airboat86]

Re: Nissan mfs6cul looses prime

Turning the motor over twice before pulling out the choke works great. I would never have tried that if you hadn't mentioned it. Thanks a lot.

 

[airboat86]

Re: Nissan mfs6cul looses prime

Today I had another hard restart. I did the two pull and choke pull routine after priming it. I had been saiing with the motor raised for 4 hours. when the motor finally started there was a gas sheen in the water. Am I flooding the motor by priming it? The primer bulb feels absolutely empty when I check it. Should I ignore the bulb and just start it?

 

[pvanv]

Re: Nissan mfs6cul looses prime

If the motor was just running, and then you tilt, the gas runs out of the carb. That can flood the intake and cylinder, leading to difficult starting. Best bet would be to run the carb down before tilting. The primer should not cause flooding. You do, after all, need gas in the carb to run.

 

[TOHATSU GURU]

Re: Nissan mfs6cul looses prime

You might want to consider running the engine by a dealer for a quick test run.