New Member Yellowtail Needs Help

[Islandtrader]

I thought I would do a cut and paste for this member(yellowtail) since his question might get buried in the other thread.


Hi everyone. I am a new member and am not sure if I am posting correctly as this is my first post but I could use some input from the group. I have a 1976 23 ft inboard Scepter and am running a 240hp Yanmar 4 cyl. diesel down here in Baja. The other day coming back in I burned up my front bearing in the v-drive for no apparent reason as it was full of oil and the cooler was working. I was lucky enough to find guy with a rebuilt drive here which he thought was a 1.5-1 like the one I had but after installing it and sea trialing the boat I found I could not get the boat up on plane at WOT. Obviously it is a different ratio. Prior life I was running a 4 blade 16x18 prop with slight cup and ran 23 -24 knots at 3000 rpm burning 7.5- 8 gals per hour. We installed a 3 blade 17x 24 and now I am running 20- 21 kts at 3000 rpm and am burning 6 gals per hour with a heck of alot of rumble but at least I am running now. Any suggestions as to where I go from here? I was very happy with prior performance of the 16x18 but have no idea how to get back to where I was and wonder if I might have been stressing the drive previously and may be better off running a little slower. I would be ok with the slower speed if I could get rid of the rumble and wonder if cupping the prop would help? Any comments would be appreciated. I will post pictures of the boat as soon as I figure it out. Thanks