Setting up Motor on new boat

[Gravelguy4]

I have a new 16' legend boat with a 40hp 4 stroke motor. When we picked it up the motor was set up on the middle set of holes (in it's relation to the height of the transom). The boat did not seem to plane out properly in this position and we were pushing a lot of water. A friend of mine who has done this sort of thing before suggested we raise the motor one notch and the boat seems to perform much better now.

i took it to a legend dealer to get a minor problem (read- the thing i broke) repaired and on my bill he has a written suggestion to drop the motor back down a notch for better performance but he did not explain why. i was in a rush when i picked up the boat and didn't notice the comment until a coupel of days later.

so, how do i know i've got it set up right. it isn't really my boat - the father in law bought it and it is in my care for a year or so - so i am nervous about messing up his boat.

any rule of thumb on this?
thanks

keith

[beachburger]

AFAIK, the rule of thumb is to start with the motor stem parallel to the transom and adjust from there. Those holes are there for a reason, to tweak the boat's performance. When you get to the point where the prop starts to lose it's "bite", you've gone too far. Also look at how the weight is distributed in the boat. Too much in the front will cause the boat to plow. Too much in the back will make it tough to get on plane. A hydro-foil would probably help in getting the boat on plane quick.

I'm guessing that since the boat has a 40HP motor, it has flooring all around, at least one console and in the back of the boat are a couple of batteries and a built-in gas tank. If this is the case, I would submit that the boat is not exactly overpowered and getting on plane might take some work if there is more than one person in the boat.

I would call the dealer and tell him what you experienced when the pin was in the original location and ask why he thinks it should be changed back. Maybe try to arrange taking him/her (or their mechanic) for a test run under your real-world situation, not a computer simulation. Most dealers will have no problem doing a "road test" with a new boat/customer.

[Gravelguy4]

Thanks for the reply BB,
You were right to assume that the boat has a floor, a single console and isn't anywhere near over powered. My father in law bought the boat and it's rated for a 50hp max so he thought up grading to the 40 would be sufficient. The weight distribution in the boat isn't ideal either but there it would take some major remodelling to adjust most of it (the console seems a little far forward). i will call the dealer and ask what his reasoning for the comment was. the motor seemed to be pretty deep in the water when in the centered position.

thanks

[beachburger]

80% of the max HP rating should be plenty to get the boat on plane, regardless of it's layout. The "plowing" when on plane might be a function of 2 people needing to sit where the console is positioned.

It sounds like you were happy with the result after adjusting the motor's tilt. You might find that the more you tilt the motor, the lighter the boat will feel on the water when on plane. It will probably also run a bit faster because the boat will sit higher on the water and there will be less drag. The downside with a motor being tilted out too much is the "hole shot" will degrade and it might take even more time to get on plane.

Happy tweaking.....

[furious]

He may want you to lower the motor in case the water pressure is low. It shouldn't be a problem going up only one notch though, you can always get a water pressure guage installed so you know for sure.