Engine height question on Classic 23"

[EagleOCNJ]

My transom was raised from original a few years back, I am removing 25" shaft twin 150s from the boat. I bought a 25" shaft 250 etec for a single application. I am going to adjust the transom to make this work.

My question is for those that have a single engine on a 70's 23 potter hull. I have read for hrs via google search and learned that the starting point is the cavitation plate being level with the bottom of the hull. Many state that the plate being 1" inch higher is often best.

What are the board's thoughts specific to the 23 potter hull sea craft. This will help me greatly and save a lot of figuring. Also, SS 4 blade prop thats on motor already will hopefully be used but dont know the specs of it.

[OSEAD23]

I would consider manual jackplate. You can get one for a couple hundred dollars and then you will be able to dial the motor height in perfectly. Do a google search or check Ebay This way you dont have to cut the transom or mess with the engine shaft length.

Pretty simple as the plate mounts the same as the motor and then the motor mounts to the plate. They make different setbacks from just a few inches on up. I have had them and they are a really slick. mine were hydraulic but for your application a manual one is fine as once you have it set right there is no need to change it.

jim

[eggsuckindog]

It does have somewhat to do with the prop, although it should be higher than you think. Mine is 2 1/2" above the hull and still won't break loose, although it is a Stillettoo and is aggreasive - Mirage is similar, lots of cup and progressive pitch. Your 4 blade should work well and you could have some cup added down the road - if your 2 - 2 1/2" I would try it first - if the Rudes still have 2 slots on the bottom mounting holes its easy to do yourself - mercs have to be pulled.

When you get it monted see where you are before you do anything - just thought of a way maybe get it close. Measure from the bracket on the motor where it would contact the top of the transom - measure to the cav plate - then measure the top of the transom to the hull bottom - should be close to where the cav plate would line up.

[EagleOCNJ]

Too be more clear, I've been told that I need a 30 inch shaft and I have bought a 25". Not by mistake but too good a deal to pass up. (2007 250 etec for 9k with 100 hrs comes with 23 proline and trlr and extras). It seems I need only about 27.5 inches so ill need to do something to make it work. Money IS and issue. So the engine needs to be lowered more than my transom will allow. An adapter kit and labor is costly, and jackplates can be as well. I'm not afraid to notch the transom a little in the center since it needs to be painted, holes faired anyway. Its currently 5 inches higher than factory. So what I'm asking is, regardless of the shaft length, where does everyones cavitation plate line up? 2.5 inches that eggsucking dog states is very good to hear. Also, is a jack plate possible in my application because I realize this situation is unconventional? Keep the thoughts coming.

[eggsuckindog]

very confusing - 5" - 27.5"- 5" above factory??? do what I said and measure the motor and the transom - they may take the measurment from the middle of the bracket, that would be 2", I don't know. As I said prop makes a big difference, my first prop I changed because I couldn't trim at all - this one I raised the motor a hole and can trim to the moon and it never breaks loose. your transom may only be 29" - need to measure both as I mentioned but I agree a little notch would be the best option - still need to measure to know how big a notch.

Stop with what people are telling you its confusing the issue and most are idiots anyway. The notch is my favorite - extension next, the drive shaft is a non isuue, money is

[EagleOCNJ]

Thanks egg sucker, you get it! im laying out more than i can afford already!

To everyone else that has a single application (and not on a bracket), where is your cavitation plate as compared to the bottom / center of the deep V? Egg suckers is 2.5" above. I was hoping to get a bunch of replies to eliminate most of the figuring!

So the shaft length is irrelevant, cavitation plate in relation to the bottom of the hull is almost a constant, no matter what the shaft length is.

The best thing about this, is that Ill have a boat again, after 2 years of sitting!

[OSEAD23]

There are manual jackplates for 200 bucs on ebay. They can be used to lower the motor just as they could be used to raise it. If done correctly you will have several inches of upward and downward adjust ability. You wont have cut your transom, far less expensive than changing your outboards length and you can dial in the anti-ventilation plate to the proper height.

the motor is aluminum the plate is aluminum its a pretty simple solution if you like..

[EagleOCNJ]

[QUOTE=OSEAD23;210234]There are manual jackplates for 200 bucs on ebay. They can be used to lower the motor just as they could be used to raise it. If done correctly you will have several inches of upward and downward adjust ability. You wont have cut your transom, far less expensive than changing your outboards length and you can dial in the anti-ventilation plate to the proper height.

the motor is aluminum the plate is aluminum its a pretty simple solution if you like..[/QUOTE

I like the sound of this thanks. Wasnt sure if this worked for my application. The mounting bolts for the jackplate will likely all end up in the under deck bait well instead of just the top 2.

I briefly looked on ebay already and it seemed to me that the units beefy enough were 600-800 bucks.

[EagleOCNJ]

BTW, what I meant was essentially, if hypothetically the motor was available in a 27.5 inch shaft, it would go right on!

[OSEAD23]

look at this one on Ebay. although it states up to 225hp

http://www.ebay.com/itm/Jack-Plate-J...42d9d1&vxp=mtr