Prop issues

[Dleopoldi914]

sorry if I write a long story here......

im in Long Island sound and bought a Montauk 17 last year with a m90a tohatsu in it. Towards the end of the season i was drifting and cast and came down on top of a rock. I went to put the boat in gear and dinged the prop.

I ran the boat for 2 weeks with no vibrations and not much loss in performance.

the old prop was an aluminum turning point hustler 13.25x17.

Boat went to mexhanic and I sent a box of spir parts I got with the boat. I had a spare prop that looks like a refurb and it is a turning point 13 21.

boat now vibrates or shakes at between 10 and 12mph.

i am thinking’s the the refurb prop is out of balance and not done right.

1.) I would need a 505 hub kit I have one that was given to me as part of the box. I would imagine thag i would need to use the plastic into the prop and then use all the old hardware. Does that sound right?

2.) this 505 hub kit does seem to have the metal in the splines does this seem ok?

game plan would be install new prop and use the hub kit I have. I will go back to the 13.25x17

pics are of new refurb prop before install, prop on the boat, and the 505 kit that I have in my Spain parts box.


what you guys think?

 

[Dleopoldi914]

Here is the 505 kit...

 

[Dleopoldi914]

I just spoke with the mechanic he told me that it is normal for engines to vibrate at certain RPMs and that it is not the prop.

Here is my thing I know for a fact the boat never did this before or maybe it did not sure the reason I know why it shakes is because my new fish finder I can see it shaking a little. Also I did notice when I ran the boat for the first time since winter that at lower RPM it was vibrating and then the more I ran it the more it stopped.....

 

[JimS123]

You need a new prop because they aren't supposed to vibrate. But before you buy one you need a new mechanic even more. Bad advice is worse than bad equipment.

As much as I love this forum, you need to try the Whaler forum because they are the absolute experts on Montauks.

 

[Scott06]

That's a heck of a pitch increase from 17 to 21" you may be lugging the motor given it's probably overpritched at this point. I'd get another 17" or get yours fixed and start there

it sure what kind of a mechanic would swap a 17 for a 21 with out speaking to you about it.

 

[Dleopoldi914]

I gave him the prop so probably assumed it was ok. Here is the prop on the boat this is definitely a 21 pitch no?

 

[JimS123]

it sure what kind of a mechanic would swap a 17 for a 21 with out speaking to you about it.

That just shows he wasn't thinking at the time. But saying it is supposed to vibrate shows he is just clueless, or didn't want to take the time to fix your boat.

 

[QBhoy]

Hi.
Trying to be straight so the point here. That refurb prop you mention is not in any decent state. It looks unbalanced, just from the picture, haha.
Generally if a prop looks refurbed, it’s not a good job. The real experts at this are capable of making a prop (especially and Ally one) look almost new. It should also be perfectly balanced.
In the extreme end of your mechanics theory...he is kind of correct. All rotational machinery of sorts have a critical rpm at which they will slightly vibrate. Usually at either end of the rpm...but with props on a boat it should not really be noticeable to the user at all really. What’s happening here is that a poor prop is either exaggerating the effect or causing it. Everything you have said and the photos tell me the prop causes this.
I might add that that’s a hell of a jump in pitch if the 17” was originally well suited. What kind of mechanic would throw a prop of 4” difference (unless you were seriously under propped originally) on the boat and tell you the vibration is normal...I hate to think.
Ask him why the massive jump in pitch and tell him the vibration is far from normal. Very disappointed in the fella to give out such advice. Worst case it can wreck your whole drive train...if not worse...shake your can of beer right out it’s holder !!

 

[Dleopoldi914]

Ok went to my boat in my marina to swap the prop. Doing it from inside the boat is a weird angle because I don’t have leverage on the cotter pin. I try to pop the pin and can’t.

i drive to the boat ramp which is around the corner and I take off the cotter pin and look at the old prop and I am missing the clamp on ring which in the instructions needs to be on the prop or else it won’t run right.

Then I notice I am missing the castle for the hub kit but I assumed it was on there.

so now I know if I drive back to my marina i won’t be able to put the cotter pin back on because it is bent and a weird angle better just start with a new pin.

there is a west marine around the corner from my boat. I tighten the prop back on and leave off the cotter pin. I use my trolling motor to get back to my marina.

i go to west marine and get the missing piece for the conversion kit.I buy new cotter pins so they are easy to put on. I put the prop back on and done.......

good lesson here.....

first pic you can see I am missing the clip on ring on the prop.

second pic I circled the piece I was missing.

thank god for west marine......and the people there are friendly....

 

[Dleopoldi914]

This is the piece I was missing.....

 

[Dleopoldi914]

Boat ran perfect tonight I even hit 35mph. I’ve never done that in this boat. Prop probably needed to be replaced for a while....