Plastic Classic Forum

Seems like the universe really wants me to learn more and more about deisel engines, or one in particular.

Went out for a glorious sail yesterday. Used the engine for about 5 minutes and that was just to ease the strain on the mooring lines in order to release them. Was able to kill it and sail off the mooring and out the channel. When it was time to come back in the channel, bow into about 15-20 kts of wind with minor seas and current, my 50 hp engine only allowed me about 2 kts of SOG.

I am assuming that this was a result of major barnicles on my prop but the situation, once back on the mooring, did not allow for me to investigate this further. Not sure how I'd do it anyway other than getting in the dinghy and trying to peer throught he murky water and see the prop. It's too cold at this point to jump in.

I had no vibration while running the engine at 20M RPM's.

Any thoughts, suggestions?

Is that 2,000 rpm? In Galveston Bay, encrustations of barnacles, tube worms, and even oysters can render a prop almost useless. Spinning it as fast as you can has limited propulsive effect. Powerboats here cannot even get up on a plane. I don't know if this is the case on the NE coast, though.

Yes, 2,000 (M is work spake, sorry).

I was able to get a gander at the propellor today and it's not pretty but it's not ugly either. My friend Nigel suggests it's fuel related. My primary filter is clear, fuel flow seems fine, temp is perfect, oil is good, but since those first two mentioned were a problem just weeks ago, I think it suggests there are more demons to be dealt with and that takes me to the tank itself. The black stuff that I sucked out of the tank a few weeks ago has been nagging me ever since. I'm told black means bacteria, not algae and the only way to get rid of the bacteria is to have the tank professionally cleaned? i.e. removing it and taking it to a land based business outfit - not the people that come to docks with their gizmos.

Is 2000 max rpm? Did it come to full RPM? If not, another potential source of your woe is the exhaust elbow. They have a habit of clogging up with carbon and rust and that prevents full power.
A friend just experienced the same problem on his Yanmar. He replaced the elbow and was finest kind again.
Best regards,
David

Hi David, I think my rpm's go as high as 3500, at least 3000 for sure. I only took it to 22, because of my recent fuel woes I was hesitant to force things too much. I think I'll get a diver down there this as that is the easy to do. I've heard that this has been a very high growth season