I've got a Vetus m3.10 diesel. I was motoring a couple days ago and all of a sudden I lost what felt like 90% of thrust to the prop. Engine was running fine, at minimum throttle in gear the boat would slowly move at what felt almost normal, but any increase in throttle would result in no increase in speed, and a metal-on-metal squeal.
Thinking I got something caught in the prop I dove under and there was nothing.( I did notice however that the new zinc on the shaft behind the prop had fallen off? -might be related).
We sailed back into the harbor and was able to slowly motor to the mooring at minimum throttle.
I checked the transmission fluid, level good and clean. I just changed the transmission fluid this spring, less than 10 hours of motoring.
We were able to reproduce the metal-to-metal squeal with me under the boat, with the gear engaged and giving the prop a turn, the shaft will spin, but the coupling does not.
Back in the boat, engine running, engaging the transmission in reverse the shaft was able to be pulled back about 3/4 of an inch from the coupling, putting it in forward the shaft is driven back into the coupling.
Looking at the Vetus diagram for this coupling, it appears that there is no key? But a pin driven through the coupling and shaft. see below:
My plan is to take apart the two halves of the coupling to see what's going on inside. Did I break the shaft, or the pin that goes through the shaft? Is there a through-pin? I'm hoping that the front part of the coupling does not need to be removed as I don't have a spanner type tool that will fit that, and it looks like with a 130 lbs it could be a bear to remove.
Anyone have any other ideas or suggestions? Things to look out for? Don't assume I know anything about couplings, yesterday was the first day I've even given this thing a good look.
PS. For those who know the main coast, we were motoring around the west side of Seguin with a west wind making it an imposing looking lee shore. I was saying "this would be bad spot for engine trouble"..shortly after which we rounded the southern tip of the island and the above engine issue happened. We were able to easily pull up sail and tack away from the island, but if had happened 15 minutes earlier we'd have been in for a fight!