Grey smoke

[shogi]

The boat will be out around February and this will be the first thing to do.
I tried it and before, but the prop is very old and the numbers on it didn't make a lot of sence for me.
Meanwhile, I'll ask the mechanic to do the compression test shortly,although the "bore glazing " issue sounds very reasonable.

 

[SandgroperWA]

Thanks folks much appreciated cheers

Thanks everyone!

 

[shogi]

Just to update….although I thought that my boat is quite clean under the waterline after the diver cleaned it I’m able to do 2600 RPM (before was 2000 RPM) and nearly 6.5 knots.
I’m still seeing some smoke (much less than before) when at full revs. In fact it is so little, that I’m not sure if it grey, black or steam….When in full revs I filled some water from the exhaust, which was black and not oily. As soon as I reduce the revs just a bit everything is ok.
I started thinking, that might be always like this and the problem was with the fouling. At least I hope so!

 

[Tranona]

Your prop is still too big. The black is unburnt fuel because you ar overloading the engine. Probably need to reduce the pitch by 2" or the diameter by 1" and pitch by 1". Then you should get around 3400.

 

[shogi]

The diver measured the prop’s diameter to be 10’’ and I’m not sure if I can reduce it further. The internet calculations are giving me a size 11”X7”.Meanwhile, a couple of quotes I got from prop manufacturers are telling me 14X7”.
So, I’m a bit confused.

 

[Tranona]

14*7 sounds more like it. Don't think saildrives had props as small as 10". You need to check the reduction ratio as there were 2 alternatives, 1.66 or 2.15:1