SB8 fuel check valve/ motor mounts

[tmason]

I'm getting air in the fuel line of my Yanmar SB8 diesel. It has been getting progressively worse through the summer -- to the point that I have to bleed the system if it sits overnight. I can't see any obvious fuel leaks. Is there a check valve I should be checking?Also, while reliable when running, this motor can shake the fillings out your teeth. Has anyone changed motor mounts? Does it help?Thanks.

 

[john]

I have the same engine with maybe a similiar

problem. I have noticed over the summer that my engine was slow to "catch" as time went on. It always starts, but a little slow when first starting up. I do not have to bleed. I contacted the Mack Boring dealer. They suggested that I replace the worn fuel lines. I went to the local yanmar dealer and they recommended carefully cutting the crimp fittings on the fuel lines and replacing the fuel line substituting good clamps in lieu of the crimps. I used an angle grinder to carefully cut-off the crimps. Step 2 . ...which I an doing this weekend is to replace the mechanical fuel (lift) pump. Mack Boring told me that there is a diaphram in there that wears with age. It may be allowing fuel to siphon back as it is worn. This is a $200 part from yanmar. One yanmar fellow suggested (off the record) replacing the mechanical fuel pump with an electric. I have purchased the electric pump at my local auto parts store. Facet makes these generic low pressure pumps. They must deliver about 2 to 5 lbs/psi to meet the low pressure requirements.My little sb8 runs well...it is a bit noisy and vibrates a bit...not too badly. I don't run it much anyway...just up to the mooring and off. If the wind is in my face, I motor into the Hyannnis channel. Best of luck.

 

[tmason]

Thanks

I had the fuel pump as a suspect. I hadn't thought of the crimp connections. We overnight at a favorite cove in the Upper Chesapeake 25 miles from our mooring. It seems like the wind cooperates about half the time, so I do a lot of motoring. On the plus side, the SB8 is extremely thrifty.