boat planes with passenger now but......

[dtg]

At full throttle I got a spray coming up between the outboard and the transom. Since I've limited use of small outboards, I've never seen that before. Is this normal? I've seen 25hp on small aluminum boats and never seen that kind of back spray. Am I being a big baby? :gaga:

[TONGA]

sounds like you have a long shaft motor on a 15" transom?
Have a look back there the cave plate should be about even with the bottom of the boat.

[dtg]

I do have a long shaft, that's what came with the boat when I got it a week ago. There's no way I'm putting out more money to make it a short shaft. I guess I'll have to live with it.

[dtg]

I measured the transom and came up with 21", so the long shaft is the proper one to use on the boat. So NOW what could be causing the spray? I saw another boat out on Wabasis last week doing the same thing.

It's not that big of deal, but it just doesn't seem right.

[TONGA]

Ok now I'm lost? I can't imagine why you are getting this problem? have you ever ran it in the driveway on a set of muffs? I only ask because the only thing I can think of is maybe you have some sort of leak in the mid or exhaust tuner and the spray is from your cooling system?
the only other thing I can think of is maybe you cave plate is broken? I will keep thinking on this but really I am at a loss? any thing else you can think of ? even if it seems non related?

[ozzgood2001]

no goofey transducer location or motor tillted funny this does seem strange my old boat with a 18 hp longshaft and a deep transom would do it on occasion when i got on real good plane was cooking along at 15 mph start spraying up and i had those hydrofoil wings on too. maybe you have those they could cause it :confused: :confused:

[dtg]

I think, at least from what I've read that the motor needs to have a board under the mounting bracket to raise it so that the cavitation plate is level with the bottom of the boat. Currently it is a little below the bottom. So I'll be trying this fix this weekend,......as long as there's no rain.

[lawnboy]

I had the same setup and the same problem.

Just put the pin out and set the motor so that it’s not pointing straight down but out at a slight angle.

[waterfoul]

The prop shaft, theoretically speaking anyway, should not parallel the bottom of the boat. This is not the most efficent angle for the prop. With the bow up a few degrees when on plane, you want the shaft parallel to the water, not the boat. So, in the driveway, check this. Is the prop shaft (the bullet of the lower unit) parallel to the bottom of the boat? If so, raise the pin one hole and see how that looks... I'd venture a guess that 3-4 degrees of tilt will take care of a lot of your problem, and make your boat more efficient to boot! On my Glastron, I have the motor on the second hole up from the transom...giving it about a 4-5 degree tilt when compared to the hull bottom. This is the fastest setting for my motor, causes the least amount of cavitation when turning, and gets me on plane in about the length of the boat (that's 14 feet!!!). I also have a set of dolphin planing fins on my cavitation plate, and I get no spray.