OK, you asked for it................. here's the long story........
Black smoke and char lilly pads shoot out the back on any kind of throttle up. Low engine output.
Cleaned or changed all filters in fuel line.
Checked compression. ok. Pretty good actually.
Checked timing. ok as far as I can tell.
Cleaned out the tank. New gas from a highly traffic'd truck stop.
The above was all done at the end of last summer.
I had no knotmeter or rpm gauge last year. Now I have a knotmeter.
The engine did perk up after all that. I was able to go from a waddle (1knot?), to actually making a little wake (3 knots?) at full engine output. The engine output stops at 1/4 to 1/2 throttle on, and the black smoke starts.
Now the engine is overheating too, as we discussed in the other post.
The engine output has again dropped to where the boat waddles. 1-1.5 knots with knotmeter. 2knots top with smoke/char starting. 1 knot or lower with proper temperature. Above that it wants to be at 100C.
One guy I talked to last week told me to check the prop for barnacles. Sounds like a good idea which I will probably do today. I am hopefull about this idea, as I can see how it could explain a lot of what has happened so far. Had boat pulled and cleaned in June.
Also today I will put in the baracle buster in the engine.