svonmiller

Thanks for the advice. The engines have 430 hours on them. It's a 1991 boat that I bought in 2008. The PO said it was well taken care of, regular servicing and oil changes. The state of the boat and the estate is was located on backed that story up. After one season, the starboard engine started having problems and I wasn't in a place to do anything about it. So I parked it, and it's sat ever since, until now. It was full of oil that entire time.

I pulled the starboard motor and it's being rebuilt. I've been reading, and apparently motor oil will gel after sitting for very long periods of time (four years probably qualifies). The engine starts and runs for five seconds before shutting down (dies like it's running out of fuel). Oil pressure won't build, and I'm pretty confident that the ECU is detecting no oil pressure and shutting off fuel flow.

After thinking about it more, I'll bet money that the gelled oil is clogging the screen on the oil pump and preventing it from pumping or priming. Or, as Andy suggested, maybe it's just lost prime altogether. Either way, that's where my issue is I'm pretty sure.

I used to build engines when I was a kid (a hell of a long time ago), but haven't since. So I pulled out my David Vizard book and refreshed my memory on re-installing the distributor. I'm confident I could get the timing back where it should be, but everyone's point is well taken - it's a lot of hassle. And anyway, I'm pretty sure I can't fit a drill and a priming tool in there anyway (no room in the engine compartment). So I'm not going to pull the dist.

I've poured diesel fuel into the crankcase and am letting that sit, hoping it'll break down the gel in the pan some. My plan is to drain that, fill again with half oil/half diesel and use a pre-oiler to prime the system. Then I'll run that half and half for a few minutes to clean the motor, the change the oil and filter again. If that all works, I'll likely change it one or two more times after that, mixing seafoam with the oil.

I plan on pulling this motor and rebuilding it too, but I really wanted to get a season out of this thing before doing it.

svonmiller

I thought I'd post an update here in case someone has a similar problem and is searching through the forums.

You were right Andy, the pump had lost its prime. I fashioned a pre-oiler out of pvc pipe and pressurized it with an air compressor. After I pre-oiled I put the sending unit back in an started it. Worked great, pressure came right up, engine purs like a kitten. I only ran it for a minute since it's got three quarts of diesel in the crankcase. But it ran nice for that one minute. Now I'm going to change the oil about 5 times :-)

Thanks to everyone for the tips.

Stan