My S150 would not start and the codes appeared to be the fuel solenoid shut off. I replaced it and I thought all was good. But, the no start issue seems to be replaced with a very slow starting issue. I have to let it crank for a solid 7 seconds or so. It is not the cold weather, as I have been dealing with this since the summer. I bought a cheaper part on Amazon and not a Kubota part. Anybody run into this or think this could be the solenoid? Any way to check, other than getting another solenoid and comparing? Thanks.
UPDATE: Upon replacing the fuel shut off solenoid again, with a different brand, the machine is back to starting perfectly. So.....a cheap fuel solenoid may work, throw no codes, but make your starting crappy.
Thanks for telling us what solved the problem. Another place to check is the glow plugs themselves or the glow plug circuit. Some of these units won't start even in summer with malfunctioning glow plugs. The type of oil in the unit will make a big difference in winter. Go with 5W40 or 0W40 synthetic to save wear on starters, cylinders and other engine parts. Oil pumps do not like 15W40 in 0F or minus 18C. Very hard to pump. Simon C
Minus 31C here this morning, just for your info. Simon C