Shaft length

[68whaler]

I had always assumed that the original '67 Rude 40 that came with my boat was a short stem but now I am not so sure. The original factory repair manual identifies the 40773 as "5" longer than standard. The cavitation plate runs about 2 1/2" below the lowest point of the center V on my 68 13'. She goes like a bat out of hell, turns on a dime and I couldn't possibly ask for better performance. Should I be considering raising the motor or "if it aint broke, dont fix it"?

 

[JB]

Re: Shaft length

I would raise it, 68. The difference in handling would be worth it alone, but it will improve holeshot and speed, too.<br /><br />You have three options. Here they are in order of my preference:<br /><br />1. Swap for a short shaft engine.<br /><br />2. Convert your engine to a short shaft.<br /><br />3. Use a jacker to raise your engine. There are some made exactly for your purpose...run a long (20") shaft engine on a short (15") transom. You would probably want Teleflex steering if you don't have it yet because the raised and setback engine doesn't like cable/pully steering.<br /><br />Some folks have built up the transom on first generation 13s to run long shaft engines. I don't like or recommend that option.

 

[Paul Moir]

Re: Shaft length

EDIT: Seems more like a J/E issue than a BW issue.<br /><br />The BTs run a little longer in the leg then other outboards. Closer to 18" than 15", although they are designed for a 15" transom. I belive this is to ensure that the water pump is submerged on start up so it'll prime.<br />Often you can jack them up quite a bit before that becomes a problem. Just make sure you've got adequate water pressure at startup, neutral and reverse. There's no problem in forward as water is force-fed into the inlet from the prop. <br />The reverse inlet on the side of the lower unit just above the cav plate must be submerged while reversing since water is actually being sucked out of the other inlet.<br />To raise the engine, try shoving sticks between it and the top of the transom. You're engine ought to be bolted on so raising it shouldn't be too difficult.<br />Have a look here and see how high Chinewalker's father is running his BT:<br /> http://forums.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=17;t=040964 <br />If you look close, you can see the lower unit seam is at least 3" above the bottom of the hull. Probably more.