I'm hoping someone might have some thoughts on my engine
dilemma prior to me ripping the head
off it to hopefully get a better idea of what gives.
40 hours of use after firing up this old Yanmar
its aggressive oil consumption
is starting to annoy and concern me.
It had sat, perhaps only operating for a few hours in 8 years prior to myself buying
(previous owner just lived in it).
I have used it regularly since (an average of 1.5 hrs engine
hours per week).
It starts really well, has plenty of power (6.5 kts in 34ft Joubert mono hull
yacht), hasn't missed a beat except it blows a bit of smoke and initially used about 45ml of oil
Now its closer to 75 - 80 ml per hour. It still runs extremely well though.
Other info -
This engine has been 'rebuilt' twice - firstly in 1998 by a firm I beleive to be very professional and a second time in 2010 by a firm perhaps less so.
The second rebuild
is fully documented and included rings and big end bearings, a proper head
refurbish (subbied out to pros) and the injectors were serviced/rebuilt.
My guess is it has done no more than 100 - 200 hours in the hands of the owner who had the work
done in 2010 and as mentioned above only 40 odd hours since 2012.
Oil I'm running is Castrol RX Super 15/40.
is between 1 to 1.7 litres per hour depending how hard I am flogging it.
I haven't driven it real hard as much of my motor
to get out of the river is 4 kt speed limit and I was wondering whether the increased consumtion under my ownership
is due to glazing up the bore a bit?
The harder you drive it, the more smoke there is which is pale blue.
The oil doesn't go black in a hurry at all either.
5 hours after a recent oil change
and it still looks quite clear.
The oil that was it it when I bought the boat
was black black though.
Thoughts engine gurus?
Heavier oil and ignore it/hope that that slows consumption?
As I intend to go away in it in a few months for 2 months I keen to make sure its going to be reliable.
Many Thanks for reading, Andrew.