re-power??

[sls233]

I have a 1976 233. Originally it was powered w/ a 351 and omc. Around 1998 the original owner repowered with a 5.7L and cobra. When I got the boat a few months ago the engine block was cracked. I purchased a remanufactured 5.7L, and began the install. I took it to the local shop to have the engine aligned. The mechanic told me he thought the outdrive was installed too low when the repower was done. He explained that the "thingamajig" part of the outdrive, sorry I can't remember the name of the part (it is a horizontal fin just above the prop), should align on the same plane as the bottom of the boat when the outdrive is in its lowered position. Well, it doesn't. It's about 1.5" lower than the bottom of the boat. He explained a number of problems this might cause. The guy I got the boat from gave me an original OMC manual for installing this outdrive. In the manual there is a chart that shows instal specs for installing the outdrive at +1", +.5", 0, -.5", and -1" (these measurements represent the difference between the aformentioned "thingamajig" and the bottom of the boat. Whoever did the outdrive install made some marks in the manual in the -1" sections, which makes me think he had a reason for installing it at that height. But he left no explanation. The manual gives no info on why to select which elevation. ANY IDEAS would be appreciated!

[McGillicuddy]

What kind of performance are you getting? Are you porpoising, or just not getting the speed and ride you expect. Motor height can have a huge effect on your hulls efficiency, especially on a hull that's made to run at speed. I think the thingamajiggy to which you refer is the cavitation plate or more correctly the anti-ventilation plate. That does seem low but you'll need to get feedback from someone who really knows. From what i've learned here, I believe Seacraft hulls are more commonly rigged with the cavitation plate above the keel an inch or so. But keep in mind that the 233 is a pure deep-v with 24 deg deadrise or thereabouts,so rigging may require different height setting. While you wait for an answer from one of the resident wizards, you might check out www.thehulltruth.com -- a lot of Formula 233 experience over there. Good luck!

[sls233]

McGillicuddy, thanks for the info. Thats what it is, the anti-ventilation plate. At the moment I'm not getting any performance because when I got the boat the motor was shot, and I have not yet got the new motor installled yet. I'm just trying to figure out this outdrive height thing first. One of the problems the mechanic said I might experience if the motor is too low is water surging into the engine through the exhaust. I really wnat to make sure there is not any issues of damaging the new motor before I proceed. If anyone else has any ideas I'd really appreciate it.