Thread:

'77 donzi with volvo outdrive - need more speed

So my buddy just bought a totally original 1977 donzi 18'.
It came with a 14x19 prop which is correct for high altitude lake tahoe.
We actually had to change the prop to the same size, just cupped.

With the original prop we got 45mph and the rpms were way too high. The cupped prop we got about 49mph at 4800 rpms.

How do we make it any faster?

Its all original so there are no trim tabs and you cannot trim that outdrive.

Thanks all

There are 3 settings and its pinned on the fastest setting.

I can post pics in a day or so

Yep,
We tried all three settings. The furthest from the transom seemed to be the best.
I would go take some pics but it is snowing. Great timing for mid May.

The guys at Sierra Boat in No Shore have a selection of props they will let you try just put up a deposit- it maybe over propped-they may be able to offer some suggestions as that boat is/ was pretty popular in that neck of the woods

Sierra Boat is literally a stones throw from my house.
There is a Sierra borrowed prop on there now.
We definately have the right prop on now.

They have been very helpful with getting this boat going. I figured that it could not hurt to hear from the pros on this site as well.