[C320-list] Engine/Fuel Issue with my 2001 Yanmar

[tjdames at comcast.net]

All,

I am hoping that someone has had a similar experience and can provide me with some guidance. As of late I have been having an issue with my engine (Yanmar - for my 2001).

When the issue began 3 weeks ago,  the engine started fine, ran for about 3 minutes, than sputtered and would not restart. When it stopped it sounded/behaved like a lawnmower running out of fuel. 

My mechanic said it had to be "primed", which he did, and it ran fine for ablut 30 minutes until he shut it off, and let it sit over night. The next morning, the same thing happened, it ran for a few minutes and sputtered out.

He now tells me that he suspects fuel is draining back to tank through the fuel sytem and he is going to "install a check valve" into the system. that will "hold fuel in system". Please note that half of my current fuel is new this year, purchased very early in the season.

Has anyone ever had a similar experience and does the mechanic's solution seem logical?

I would appreciate any thoughts! 

Thanks,
Tom Dames
Whisper 708