Westerbeke 8.0 KW engine

My Westerbeke wouldn't start at the end of last season after sitting unused for 6+ weeks. Got it winterized and started working on it this season to analyze the problem. Changed fuel filters and bled system, checked glow plugs, pulled injection pump and injectors and sent to rebuild shop. 2 injectors were bad so I thought I had located the problem but no joy. It still wouldn't fire up, so I then purchased a kit to check compression, I didn't think this was a problem because it didn't have excessive blow by. #1 510 psi #2 215 psi & #3 180 psi, I then figured the head gasket was blown between #2 & #3, could hear air hissing during cranking that added to this feeling. Pulled the head and no sign at all of gasket failure, I then removed the generator and hauled home to my sons shop because he has all of my tools now. Tore it down yesterday and found that everything looks very good inside, the bearing inserts look new, cylinders aren't scored, pistons still have machine marks on the skirts. The pistons have 3 compression rings and 1 oil control ring. The problem was all the compression rings were stuck in the grooves on the 2 with low compression and only the top ring on the other piston expanded out of its groove. A little more information #1 had a little rust in the cylinder when the head was removed so at some point it ingested water possibly during cranking.
Now the question for those still reading what are you ideas on the cause of the stuck rings?

your gauge is toast?

510psi ~ 35:1 compression.

kev_rm said:

your gauge is toast?



510psi ~ 35:1 compression.

Click to expand...

Possible, new gauge but of unknown quality if came with the kit. But there is no doubt about the problem only what caused it.

If that wasn't a typo your gauge is not possibly toast, definitely toast. Your generator would be in the range of 20:1 compression. You're already making assumptions based on its readings. You've no idea if those rings were in fact leaking compression during run time.

Except for the findings on breakdown and (assuming the gauge was reading wrong constantly) the vastly differential readings.

BruceK said:

Except for the findings on breakdown and (assuming the gauge was reading wrong constantly) the vastly differential readings.

Click to expand...

My thoughts exactly, I had to use the tools available and the difference between cylinders was key to pulling the head and then the pistons. The rings seized in the grooves was proof to me I had found the problem. I've rebuilt a lot of diesel and a few gas engines over the years so I'am not a rookie at analyzing a problem. The initial question about the cause was my reason for the post. I think I know what caused it but was looking for other opinions.

Running it unloaded? Never changing the oil? Overheating? Solar eclipse?

Head is off..pour as much marvel mystery oil into the cylinders as you can and let it marinate. See my post on alternate suppliers for Mitsubishi parts. Weaver Tractor in Pennsylvania may have a $70 Mitsubishi head gasket instead of a repackaged one from Westerbeke for $211. Good luck.

Thanks Mule I did save that information when I read your thread. I have sources for parts much more reasonable than Westerbeke.
Xsbank the oil and filter since I've owned it has always been changed between 90 to 100 hours. Never ran with no load but I believe that light loading may of been a contributing factor, the PO always ran it whenever he left the slip and I doubt he had much of a load on it. Getting it out was a genuine pain in the a$$, that was one reason I didn't replace with a new 5.5 to 6.5 kw unit. The head has to be replaced once it's back in place & I didn't want to remove the head on a brand new unit because of warranty concerns. Later models of my boat have a hatch over the gen that makes maintenance and replacement much simpler.

Rings can stick from moisture or from soot, soot from low load running. Can soften it up with outboard two stroke ring free or other solvent. Or pop pistons out and loosen by hand with solvent. Note that some westy 8's have four rings and the mitsu specs show three rings. So unless you want to buy rings from westy, loosen up and reuse the old ones.

I had the same problem with a smaller 5.5 kW gen set on my former sailboat. It sat for a month and then would not start. Sprayed some oil in air intake and after a few cranks it started up, albeit a bit rough. After running for a min or so, smoothed out. Later, in talking to Diesel engine guy, he said that sometimes diesel motors that are not run for a while, develop a layer of fine rust on pistons, rings and valves. All combined to thwart compression, so no start. If I know I won't be using the motor for a while, I give the intakes a brief squirt of engine fog oil to coat the internals. good luck.

During the effort to find the problem I pulled the glow plugs and gave each cylinder a squirt of oil. I rolled it over a couple of times and then left it sit for a day. This didn't help so I repeated the process and still no help getting it to fire up. I should also mention that I cleaned all the battery connections and had the starter rebuilt at the beginning of the problem. After changing all the fuel filters, checking flow and bleeding the system, this was the 1st thing I did to make sure it was spinning over fast enough.

".pour as much marvel mystery oil into the cylinders as you can and let it marinate."

A friend at a large company had MM oil analyzed .

Its #1 diesel , with coloring and oil of wintergreen to change the smell.

Save your money . ATF is a better , and is PB Blaster , but the stuff for removing carbon from outboards is probably the best.