do i need a new prop with a diffrent pitch??

[chef master]

i have a 1975 browning fishmaster 1 16 foot deep v boat with a mercury 85 hp motor i just bought a few weeks ago and ive noticed that when i go half throttle on the motor it planes nice but when i open it up and go full throttle the bow goes to far down in the water and the boat does not plane at all the tilt is manual pin in hole kind and i have ajusted my motor to all of the holes and still not plaining out my prop is a 13x19 do i need to change the pitch of my prop to somthing lower like a 14x17 or 14x16 or higher like a 14x20 or 14x21???

 

[roscoe]

Re: do i need a new prop with a diffrent pitch??

I would say no.
Your boat is getting up on plane at half throttle, so you there is no reason the boat should not stay up on plane.

Is the motor mounted directly to the transom, or is there some kind of jack plate being used?

 

[chef master]

Re: do i need a new prop with a diffrent pitch??

yes its mounted directly to the transom no jack plate no power tilt and trim, and thats even with just me in the boat with a 6 gal tank of gas 2 batt. and a couple rods and i only weigh 200lbs

 

[steelespike]

Re: do i need a new prop with a diffrent pitch??

I hope I'm wrong.I suspect the bottom of the boat is distorted .It may have a hook, a depression in the area ahead of the transom.
On the trailer lay a straight edge along the keel and note any space between the bottom and the straight edge.
Also if the floor is spongy or has been rebuilt they may have not done it properly.
Also check the transom Take a hold of the motor and push it front to back and watch for movement in the transom.
If its weak in the extreme it may flex and the motor will lose its trim.

 

[chef master]

Re: do i need a new prop with a diffrent pitch??

yes when i push the motor back and forth it moves the bottom of the transom is rotted and i am going to repace it very soon coult a rotted transom do that? i will also post a couple picts soon and can you help me and tell me how to remove the transom out?

 

[steelespike]

Re: do i need a new prop with a diffrent pitch??

If the transom is weak its very likely the bottom has problems as well.
There is a restoration forum where they can help with repair procedures.
You should definitely check the bottom. And I do know when you start taking it apart you will need to support the hull so it retains or regains its proper form.

 

[chef master]

Re: do i need a new prop with a diffrent pitch??

even with a aluminum boat ill have to support it??

 

[steelespike]

Re: do i need a new prop with a diffrent pitch??

I was assuming fiberglass but you still may need support depending on if the metal support is enough as you remove the wood.
Is the bottom smooth,no dents or hollows near the transom that might cause the bow to lay down?
No broken supports. that may allow the bottom to flex?

 

[chef master]

Re: do i need a new prop with a diffrent pitch??

no its smooth and the transom wood is between 2 pieces of aluminum

 

[steelespike]

Re: do i need a new prop with a diffrent pitch??

Looks like your all set to go to it.I added an angle iron across my transom when I rebuilt it many years ago.
I assume you don't have a hydrofoil/whaletale on the motor?

 

[chef master]

Re: do i need a new prop with a diffrent pitch??

Looks like your all set to go to it.I added an angle iron across my transom when I rebuilt it many years ago.
I assume you don't have a hydrofoil/whaletale on the motor?

yes i do have a hydrofoil on it took it off and no diffrence
here is a pict how can i remove the transom on this boat i can remove the cover ontop of the transom but after that there is about 3 inches on each side thats aluminum i cant move without cutting but there is about 6-7 inches in the boat from the drain plug to the transom that there is no wood