Technical

I had assumed that the timing was off on the Golden Fleece I have. Reverse running it runs fine, but forwards it stops with port side con rod just above fully aft, and starboard side just in front of up.

But with the port side con rod disconnected from the wheel it still stops here. I wondered if the steam port was blocked but the starboard piston successfully pulls again after it passes this dead zone , albeit less strongly. Looking at the port side crank positions, with the port con rod off, the wheels move briskly from 12 to 7 o’clock, and from 6 to 3, but need nudging to 2 before carrying on to 1.

There isn’t an obvious leak from the piston gland, and I can’t think what would only affect forward motion like this. Has anyone seen anything like this?