from the crankcase of our starboard engine
is being shot out of the dipstick hole into the bilge
. Our 2GM20 Yanmar
used to do it once or twice a season, but this year it went first to 6 weeks, then 4 weeks and now it seems weekly. We never notice any trouble, then bang, a big mess and the dipstick is loose. I mentioned it to a mechanic
at Fred Marine
in Pointe-A-Pitre, and he said it was most likely a bad diaphragm
in our fuel lift
pump. The lift
pump runs off a cam inside the engine
block, and if the diaphragm
can leak into the crankcase until it is a problem. He sold me a "rebuilt" pump for 50 euros, and, after my guests were gone and we were in Antigua
, I put it on and started the engine. Worked like a dream, so we started to lift anchor
when the engine raced out of control. By the time I had gone down, dug down to the engine, and stuck my hand over the intake, there was a big mess coming out of the exhaust
. I checked the dipstick (I had also wedged it a little tighter) and when I pulled it out a half litre of oily fuel poured out of it. The fuel had got so high in the crankcase that it travelled through the crankcase breather, around the tube to the air intake, and the engine took off!
I brought the boat into Jolly Harbour, Antigua
, and started up a relationship with the mechanic
: Carl Mitchel. Nice guy, really. I took off the injectors and he tested them as well as the two fuel lift pumps. My old lift pump worked while the "rebuilt" one was truly faulty, and had nearly destroyed my engine and/or boat! Carl also believes the problem of disgorging oil
out of the crankcase is a matter of fuel getting its way in, but believes it can only be via the high-pressure injection pumps. Makes sense, as that is the only other location that fuel enters the exterior of the engine, with all fuel piping being exterior. As few people work with these pumps, he said he'd only take my pumps out if he had another to slide in - he is looking, while I keep sailing around Antigua. The engine is available, but I seldom use it.
There is a carbon buildup that only shows itself when we run it around 2500 rpm
. Otherwise the engine runs like a dream and Carl does not suspect any problems with piston, cylinder, rings.
Any one with experience or ideas, or opinions on this? It may not be an issue of fuel in the oil, as I really couldn't tell from the mess in the bilge
each time, but it makes the most sense.