1947 Century
 

My good friend's father in law just finished restoring a 1947 Century. The boat is beautiful (awaiting pictures). The question that has been presented to me is how to connect the engine to the prop shaft. I feel the engine that is going into the boat may not be original, hence the driveline issues. I know the trans is a Velvet drive, but don't know much about the engine. It does have Offenhauser valve covers and a very low profile dual carb intake system.

Any guidance would be helpful. Thanks in advance.

V drive or straight inboard?

It is an inboard, but has the Velvet drive on the back of the engine.

The prop shaft should go directly into the transmission coupler and held there by a pair of set screws as well as a keyway. http://kfulford.globat.com/SkiNautiq...ter_hookup.jpg

Here is the coupler

needless to say, the coupler has to be the correct size for the propshaft. so first get shaft diameter and see if keyway has been machined into it. shafts are usually on even 8ths of an inch. 1-1/8, 1-1/4, 1-3/8ths or in this size boat mebbe 1 inch even. see if velvet drive has flange on back that looks like it will match up to payupp's pic. it should. unless it has been removed from trans.

There's definable a flange on both trans and prop shaft. I guess the issue the owner has is the height of the engine in the cradle....he feels it's too high. He wants to add a u-joint to the prop shaft and the trans so he can lower the engine in he cradle.

I'll try to get those pictures today.

get ready to spend the better part od the day with a feeler gauge lining it up for zero runout, did my dads chriscraft with him had to jack the motor around for several hours to get it all lined up so there would be no vibration issues.. get on those pics..rm

You don't use a u joint for this type setup. The engine location is determined by the propshaft/strut. It'll sit at an angle, higher in the front.

as payup says, this is a straight shaft setup. you gotta take the mountain to mohammed on this one. all engine-trans mounts have to be freed up so they can be adjusted and engine must be moved so the 2 flanges line up PERFECTLY. there is a LITTLE wiggle room with shaft but only in up-down or left-right. the angle between flanges has to be dead on. so if u shift shaft up to reach motor, you need to tilt motor down more for angle alignment. if engine is too far from shaft for adjusters to take up diff, the physical mounting point for engine-trans has to be relocated. ie lift motor and add shims under front or rear mounts, or sounds like in this case, remove motor and cut stringers down or relocate mount pad till motor-trans line up closer to shaft.

Like Payupp and Derek have said, the engine is dictated by the shaft. Have you ever seen a Correct Craft Ski Nautique? The front of the engine is pointed at the windshield (basically), I just learned all this on the SN I had, and if I remember right the tolerances between couplers was .0003 or less, top, bottom, left and right, between the couplers. On the SN it has an adjustment on all four corners (mounts) of the engine, and it took the better part of the day to get right, and if this process it's not done the shaft can break.
And if the stringers that they are mounted to are not solid, the adjustment will change!

They asked me to help with this project. I know the engine was mocked up once, but they felt something wasn't right.

Thanks for all the input.

If money is no object, you can get a down angled tranny and mount the engine flatter but you prob dont need to. Just copy the original setup.