I have a pretty convaluted situation. I currently own an '89 Maxum 2000SR 230HP 305 GM/Alpha One, or some such, pretty nice boat, but I have some issues with it.
1) The biggest problem is that my first trip to the lake this year found a crack in the lower unit gear box. The lower unit was whining a bit, so I trailered it to top off lower unit gear lube. When I removed the lower drain plug, a significant amount of water came out. "That's bad", I remarked. When I optimistically went to fill with oil, found the oil leaking onto the ground at the forward of the "bullet" shaped lower unit gear box. So this is really a compound issue... there was water where there was supposed to be oil, indicating a seal problem probably; and because I didn't winterize a gearbox that wasn't supposed to be full of water, the casing cracked under the stress of the expanding ice that wasn't supposed to be there.
2) a couple spots in the floor are starting to give under my weight, mostly around the center storage area in the floor between the front seats. The seats have begun to deteriorate, screws pulling through old wood, etc, and the vynil on the seats and around the sides of the open bow is aging, cracking, etc.
3) I have a limited amount of emotional attachment to this boat. My first love will always be my long lost '69 Mark Twain 18' V-Sonic. Anything else is a meager stand-in to fill the void.
On the plus side, the powerplant (230HP/5.0LX) has always performed magnificently.
The most direct solution is to purchase a replacement lower unit, or just the casing, and then solve the unknown seal issue. This solution starts in the $1000 range and goes up from there.
Enter point #3. I did some hunting and found a 18' 1969 Mark Twain that's in good shape for its age, though its 160 HP 250cid inline-6 GM has a cracked block. It does have a good Merc Type I drive unit.
At this point I am contemplating purchasing the Mark Twain, and moving components around in various confiurations to get me back into my Twain.
First option: Move the 305 in place of the 250, keeping all the original drive components, gimbal housing, transom plate, bell housing, etc of the 1969 160HP setup. Only the V8 itself, motor mounts, exhaust setup, etc, would be installed in the Twain. Possibly through-hull exhaust may be added if refitting the V8 exhaust is too difficult. The Type I has a 1.65 gear ratio, and the Alpha One has 1.5 gear ratio. I suspect that those ratios are close enough that I can fine tune with prop pitch adjustments, if at all.
Second Option: The research I have done states that the lower unit gear boxes were somewhat interchangable, though most mention addressed replacing older Type I lower units with newer MR/Alpha lower units, not the other way around. If it's possibe, then bolt up the old Type I lower gear case onto the Alpha One upper unit, and move the whole kit and kaboodle over to the Mark Twain, including the engine, transom plate, bell housing, gimbal bearing, upper drive unit and lower old drive unit. The question then is if the Type I transom hole in the '69 Mark Twain would support the Alpha One transom/gimbal parts, or would I be rebuilding up a new transom so I can proceed to cut out an appropriate size/shape hole for the '89 Alpha One parts.
Third Option: Pretty much the same as the second option, but add in the replacement lower unit. Yes, I love the Twain that much.
Fourth Option: Find a replacement 250cid block for the cracked block, rebuild it using all the existing good internals, and live, love, my 160 HP Twain.
What do you think? I really need some advice here as to what is possible, and what is realistic. I have done enine rebuilds/swaps before, both automotive and marine, but don't have any experience with fiberglass work, though would attempt it to get my Mark Twain back.
Thanks in advance.
Gwidion
1) The biggest problem is that my first trip to the lake this year found a crack in the lower unit gear box. The lower unit was whining a bit, so I trailered it to top off lower unit gear lube. When I removed the lower drain plug, a significant amount of water came out. "That's bad", I remarked. When I optimistically went to fill with oil, found the oil leaking onto the ground at the forward of the "bullet" shaped lower unit gear box. So this is really a compound issue... there was water where there was supposed to be oil, indicating a seal problem probably; and because I didn't winterize a gearbox that wasn't supposed to be full of water, the casing cracked under the stress of the expanding ice that wasn't supposed to be there.
2) a couple spots in the floor are starting to give under my weight, mostly around the center storage area in the floor between the front seats. The seats have begun to deteriorate, screws pulling through old wood, etc, and the vynil on the seats and around the sides of the open bow is aging, cracking, etc.
3) I have a limited amount of emotional attachment to this boat. My first love will always be my long lost '69 Mark Twain 18' V-Sonic. Anything else is a meager stand-in to fill the void.
On the plus side, the powerplant (230HP/5.0LX) has always performed magnificently.
The most direct solution is to purchase a replacement lower unit, or just the casing, and then solve the unknown seal issue. This solution starts in the $1000 range and goes up from there.
Enter point #3. I did some hunting and found a 18' 1969 Mark Twain that's in good shape for its age, though its 160 HP 250cid inline-6 GM has a cracked block. It does have a good Merc Type I drive unit.
At this point I am contemplating purchasing the Mark Twain, and moving components around in various confiurations to get me back into my Twain.
First option: Move the 305 in place of the 250, keeping all the original drive components, gimbal housing, transom plate, bell housing, etc of the 1969 160HP setup. Only the V8 itself, motor mounts, exhaust setup, etc, would be installed in the Twain. Possibly through-hull exhaust may be added if refitting the V8 exhaust is too difficult. The Type I has a 1.65 gear ratio, and the Alpha One has 1.5 gear ratio. I suspect that those ratios are close enough that I can fine tune with prop pitch adjustments, if at all.
Second Option: The research I have done states that the lower unit gear boxes were somewhat interchangable, though most mention addressed replacing older Type I lower units with newer MR/Alpha lower units, not the other way around. If it's possibe, then bolt up the old Type I lower gear case onto the Alpha One upper unit, and move the whole kit and kaboodle over to the Mark Twain, including the engine, transom plate, bell housing, gimbal bearing, upper drive unit and lower old drive unit. The question then is if the Type I transom hole in the '69 Mark Twain would support the Alpha One transom/gimbal parts, or would I be rebuilding up a new transom so I can proceed to cut out an appropriate size/shape hole for the '89 Alpha One parts.
Third Option: Pretty much the same as the second option, but add in the replacement lower unit. Yes, I love the Twain that much.
Fourth Option: Find a replacement 250cid block for the cracked block, rebuild it using all the existing good internals, and live, love, my 160 HP Twain.
What do you think? I really need some advice here as to what is possible, and what is realistic. I have done enine rebuilds/swaps before, both automotive and marine, but don't have any experience with fiberglass work, though would attempt it to get my Mark Twain back.
Thanks in advance.
Gwidion
