150HP motor, 17' Boat, Prop

[jddenham]

Hello and thanks for reading:

I bought a 1975 Mercury 1500cc inline 6 cause it was a good deal. I have a 17' boat that is rated for 135HP from the 70's. It is a V-hull, kinda performance looking style, closed bow. I am going to strip it down and do new stringers, floor, and transom.

Is there a law against putting the bigger motor on this boat?

Since I'm rebuilding part of it can I strengthen it and have it recertified as 150HP?

Any tips on the transom rebuild to accomodate this motor(I'm using a manual jackplate) ?

Oh and my main questions was will this prop fit it:

http://cgi.ebay.com/ebaymotors/ws/e...e=ADME:L:AAQ:US:1&viewitem=&item=180044955992

It was cheap so I thought I'd risk it!

Thanks!

 

[jddenham]

Re: 150HP motor, 17' Boat, Prop

One more note:

It's NOT the boat in my avatar!

It's a 1973 'Las Vegas' 17' with a newer style rectangular windshield. I got it for $20. It needs a new transom.

 

[AlanR]

Re: 150HP motor, 17' Boat, Prop

Alright, lots of questions here Ill do my best and awnser them all.

Theres no "law" on putting a bigger motor on that boat. Im in the process of putting a Gt 150 On a 14 ft fiberglass boat.

Yes you should re en force the transom with some aluminem or stainless steal, Replace the wood then wrap the transom in aluminem, and run bolts in to the transom well from the transom ( I ran long bolts ) gives alot of re en force ment.

Anyways last but not least that prop will NOT fit youe motor. its for a merc crusier and it will not fit. the Splines will all be off and im pretty sure its a diffrent hub all together.

Hope i havnt discuraged you.

Have fun! Ask questions and post pics! We LOVE pics!

 

[tashasdaddy]

Re: 150HP motor, 17' Boat, Prop

if you are planning on insuring the boat, that is over powered. they will insure it, but likely will not pay off. lawyers love this. it's called safe operation. and yes you can be sited by the authorities for an unsafe boat., go on ebay and fine a 1350 cowl, it will fit. i had a 1350 with an 1100 cowl. then paint over the number on the mid section. i didn't tell you to do this.

 

[jddenham]

Re: 150HP motor, 17' Boat, Prop

I looked up the prop part number on this very site:

http://www.iboats.com/mall/propfind...d=3581&session_id=214831043&cart_id=164616625

it looks like it is compatible?

If it fits the shaft and looks good is that all that matters? I don't want to harm the motor by running the wrong prop.

 

[Texasmark]

Re: 150HP motor, 17' Boat, Prop

'75 150 should prop rate at 115 if I read all the chatter on this forum correctly over the past year. So, by today's standards you are OK. Somebody said that in the late '80's is when they changed from "brake" hp ratings to "prop" ratings.

So now you are talking about a 115 on a 17' boat. First thing you need to know is the gear ratio of the engine and what kind of hull you have.

Then you need to go over to props and talk with Walleyehed.

Mark

 

[Texasmark]

Re: 150HP motor, 17' Boat, Prop

Think I was wrong about the mounting bracket. Looking at it again it looks like an after market PTT.

Mark

 

[jddenham]

Re: 150HP motor, 17' Boat, Prop

'75 150 should prop rate at 115 if I read all the chatter on this forum correctly over the past year. So, by today's standards you are OK. Somebody said that in the late '80's is when they changed from "brake" hp ratings to "prop" ratings.

Well the hull being a 1973 also shares the same rating of HP at the crank. If I were to put a prop rated motor on, it would be around a 90 - 100 HP model I think?

Anyway - I think I will look for a 115, 125, or 135HP cowling so that I can worry less. Not that I've seen the Coast Guard roaming the snake and clearwater rivers of Idaho LOL.

I did get stopped by the Sheriff once for allowing my 3 year old to man the 'ski flag'.

 

[jddenham]

Re: 150HP motor, 17' Boat, Prop

Think I was wrong about the mounting bracket. Looking at it again it looks like an after market PTT.

Mark

Not sure what you're talking about here, but here's a pic of my motor with the trim/tilt removed:

http://www.james.denham.com/Web photos/merc150.jpg

I have all of the hardware and will be installing it on the boat. As far as I know it is OEM original stuff.

 

[AlanR]

Re: 150HP motor, 17' Boat, Prop

BOLT DOWN UR MOTOR!!! dont just use the little screw things that clamp it to the transom. Ur motor will go to the bottom of the lake... Ask around on this forum and I bet every ones lost a motor or almost lost a motor a couple of times. Ive lost alot of motors and every year atleast 2 of my motors fall off. Just thought id tell you so you have something to look into