| Author | Message | ||
     Scott Corder (Pastcommodore) Rating: N/A |
I want to say that I have posted regarding this issue elsewhere on the board but will elaborate here anyway. Basically, KATO's advice (although very simply stated below) is recommended VERY highly. The proper "match" of prop size and pitch to the engine depends ALOT on the Yanmar gearbox. I have what appears to be a very large (heavy looking hub) martec while most others I have seen look quite light and smaller in the hub. When I called Martec, they indicated that the gearbox (gear ratios) determine what size and pitch of prop should be used. They said the gearbox or clutch could easily be burned out by an improper match. Here's the troublesome part: There were several gearboxes delivered on the 2GM and there is no rhyme or reason as to why and when... as far as I have been able to learn, they just used whatever gearboxes they had on the shelf as they were building them. Thus, there is NO on-size-fits-all answer to this question. Lance's comments on proper operating RPM are also well-founded. The folks at Martec indicated that maximum propulsion (boat speed) should occur somewhere around 2900 rpm for the 2GM. Again, Martec was able to explain this in great detail over the phone. Best bet? Call Martec with the info KATO suggested. They'll advise accordingly and can be very trusted in my experience. |
