Originally Posted by simmons0
We have the same Mercruiser 1.7 in our boat, no problems with the engine yet, but it does seem to be running a bit smokey.
If you do a search on Mercruiser diesels there is a thread where a couple of people say their's has suffered holed pistons.
Edit: Found it: Mercruiser 1.7 dti engine failiure
As to running smokey, are you running any diesel fuel additives? Also are you allowing a cool down after running it hard? How many hours do you have on it?
I'm running a diesel additive that has definately reduced the knock/rattle of the diesel and I also let it idle for several minutes to cool the turbo oil before shutting it down. I only have 30hrs on the boat and no smoke at all. I've run about 500 miles (gps) so far. I do a lot of trolling which seems to use almost no fuel. Cruise speed is 28mph at 3800rpm, 5-6mpg depending on sea conditions, turning a mercury mirage 15.5x17pitch prop. Top speed is about 32 mph. No race boat but it sure does pass the fuel dock a lot!
I read the links and would love to figure out what the holed piston boat is turning for a prop/weight/length/ etc. He states several divers, gear, turning 3100rpm and NOT on plane? May just be a case of overloading the engine. I also hear a there was a problem with the waste gate shaft sticking that allows the engine to over boost when heavily loaded. Wonder if this boat is trailered or stayin the water? I would hate to loose a piston 100 miles out in the gulf of mexico! Arlon