I pulled the exhaust
elbow - no big carbon build-up at all. Yes there was some but nothing real bad. Exhaust side of the turbo has a blob of carbon buildup about the size of a quarter - not on the blades but near the flange that mounts the exhaust elbow.
I pestered the local Yanmar
expert for about an hour and we reviewed the entire scenario and history
. I also spun a known good turbo unit he had in the shop and it feels the same as mine. Don't think it's the turbo at all.
One thing I had not done is change the secondary fuel filter
- the 2 micron unit mounted on the engine. I will change that before we launch again.
I remember that after we first took delivery
and made the trip from New Orleans
to TX, we had black soot in the wake. We made 7 kts at only 2200 RPM
, and I honestly cannot remember if the engine ever spun up to its rated max of 3600.
I'm going to gather the prop specs and tranny ratio and go figure out if I have the right prop.