Hi Thanks for the replies.
I have removed injectiors, whilst no obvious signs of damage have been unable to get checked.
It would seem what i have descibed as brown smoke / sludge is in fact black (light playing tricks) whilst trialing after doing further checked we recoved some of the "sluge" emitted from the exhaust
and appears to be carbon / soot.
Whilst checking the air filter which was supposed to have been replaced on last years service
, it seems to have been burnt or not replaced for some years and degraded / burnt. Concerned part of filter could be in air inlet manifold and decreasing air input.
Running with no air filter did not change amount of smoke in fact seems to be getting worst.
It would seem engine is carboned up, have tried to check the mixing elbow
on the 3gm30
but can not see how it come off.
Any advice, on how to determine if black smoke is lack of air or too much fuel
Although some weed is on the boat it is not as bad as when purchased so don't feel its down to this.
Does it pay to try and run engine hard to remove and try to clear?
Have attached pictures.
Thanks for your help