Changing to a Piranha prop - install question

[tmh]

Hi. Mercruiser Alpha 1 outdrive. Existing prop was a 3-blade aluminum (19'p I was told, but can't find it on the prop). I'm putting on a Piranha 4-blade - I have 18p and 16p blades for it. Here's the question:

I slide the old prop off but the Piranha only slides on far enough to put the prop nut on about half way. I'm doing this under water, so I feel another washer on the shaft (large washer on the base of the shaft) that is keeping the Piranha from sliding down all the way. I don't know what this large washer is for - is it for the previous prop and removable to install the Piranha? or is it ALWAYS need to be on there?
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The Piranha seems to fit on fine if I remove this washer. Is this OK?

 

[Crownie2]

Re: Changing to a Piranha prop - install question

I am fairly certain that Piranha could answer this question for you...

Bob

 

[walleyehed]

Re: Changing to a Piranha prop - install question

It's very simple...the prop you have does not match the thrust washer you have...
You have 1 of 2 potential problems..#1 you have a prop now that requires something other than the original thrust washer, or, #2, you have a Piranha that is not the right model for the Alpha drive.
Make 100% sure the piranha is for the Mercruiser alpha.
You don't have a prop on there with a 2/3 piece hub do you??(the old prop)

 

[tmh]

Re: Changing to a Piranha prop - install question

Thanks Kenny. I have the correct Piranha - just bought the correct hub and checked/double checked to make sure it for mercruiser Alpha 1 outdrive of my size hp.

However, it is certainly possible the aluminum prop that was on there had a different thrust washer than the original to make it fit. So, maybe my Piranha just didn't fit over the thrust washer correctly.

OK, I ran it a short distance without the thrust washer on (so the Piranha would tighten down OK). Will that cause a problem?

I'll check the thrust washer next time I'm at the marina.

Thanks again.

 

[Crownie2]

Re: Changing to a Piranha prop - install question

If Kenny is right, all you need to do is get a Merc thrust washer...

I wouldn't run it much without it.

Bob

 

[tmh]

Re: Changing to a Piranha prop - install question

OK, so I called Piranha and they said it is correct to install the hub without the stock thrust washer - it's built into the Piranha hub as I was told.

So it looks like I'm OK. Can't wait to put it through the tests! Thanks for the help.