If a boat has been (and still is!) overpropped for years, and therefore has never been run past approx 2000rpm (yanmar 2gm), will it hurt now to slowly try to bring it up to max rpms (WOT)in neutral?
I cannot bring it anywhere near max rpms while in gear
, as white smoke will come out, and I don't want to overwork the engine
to the point of causing damage!
Explanation - just installed a new magnetic pickup tach, as the boat never had one, and i wanted to know my rpms. The specs say 97 teeth on my engine
. I set the teleflex guage is for the range 90-110 teeth - it may need calibration, but I think is somewhere in the ballpark, as idle shows about 800rpm.
I can rev to about 3000 in neutral - may go more, but I didn't want to damage it!
Will put out white smoke above 2200 rpms (again guage may be off some).
On my 30' med displacement
(9000-10,000lb) sailboat, I can do 5 - 5 1/2 kts around 1800-2000rpms, but will smoke it I try to go above 5 1/2 or 6 kts. I know my hull speed
would not be much greater thna 6kts, but I am nowhere near cruising rpms (approx 3000rpms) at this speed, and white smoke starts coming out.
PS the engine works / sounds very good until it revs to the point of white smoke - does not overheat, etc!
I thought it was overpropped anyway as it has a 15" x10 3 blade
prop - the prop caclulator showed I should have something like a 15" x 7.4 or a 14" x 8.6.
I will likely have some pitch
taken off, once the boat is hauled in the fall, but want to know that it will not damage it more as is.