Hustler prop hits trim tab - Mercruiser Alpha

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rparge

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I thought I'd try this prop as a spare, and was test fitting it, and there is no way this can be right, yet I have all the right numbers according to the mfg web site. This is on an 2007 Alpha 135 3.0 sterndrive, and is a 21 / 14.25 RH prop.

I have the H1421 and the 31 hub kit.

The OEM prop has an inset in the prop where the thrust washer fits, and on the Hustler, the washer just sits on top of the hub kit. Therefore the prop sticks out half the width of the thrust washer, and hits the trim tab.

Anybody have and experience with this set up?

Thanks!
 

WillyBWright

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Re: Hustler prop hits trim tab - Mercruiser Alpha

No experience with Hustler props, but I've notched a few trim tabs in the past to permit clearance. If your 3L happens to have power steering, you can cut it off altogether. They are not necessary with power steering. Most with power steering come with flat plates there. But I'll bet the drives with the 3L gear ratio automatically come with trim tabs because not all 3Ls have power steering.
 

Bondo

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Re: Hustler prop hits trim tab - Mercruiser Alpha

Ayuh,........

There are Atleast 3 different Anodes that fit there,......

A Large 1,..... I'm Guessing that's what Your's is,.....
A Small 1,.....
And the Flat Plate that Willy mentions.......

You can either Change it,....
Or as Willy says,..... File it to Fit.......

1/4" Clearence is Plenty.......
 

Texasmark

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Re: Hustler prop hits trim tab - Mercruiser Alpha

Does the OD of the prop marry up to the gear housing properly.....like the old prop?

Mark
 

rparge

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Re: Hustler prop hits trim tab - Mercruiser Alpha

Thanks for the all the replies.

The prop OD is the same, the physical make up of where the rear thrust washer fits does not allow the prop to seat all the way in, like the old one.
It physically sits out a good half an inch compared to the original.

The thrust washer sits down in the OE prop, and it sits on top of the rubber insert (?) of the Hustler.

Here's some pics.
OEM1.jpg

OEM2.jpg

AM1.jpg

AM2.jpg



When the thrust washer is in place on the OE, I can not move it side to side, as it sits inside that casting, yet on the Hustler, it just sits on top of the core, and you can move it all over the place.

TIA
Rick
 

Texasmark

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Re: Hustler prop hits trim tab - Mercruiser Alpha

I just went out to the shop and took my Hustler out of the box. The mating part looks like yours. So I'd say you are ok on that end for now...see below.

The offset on the front of the adapter is there to accept a grove in your thrust washer which would lock the front in place like the OEM. I examined mine and there are grease marks on the face of it where that was the case on mine since I have run this prop (23P) and had no interference problems with the trim tab.

I did not remove my prop and examine the thrust washer but as I recall there is a slight raised area close to the shaft which would fit into the groove of the plastic collar on the front of the Hustler's insert.

Your washer is sitting on top of the plastic, not in it and explains why your prop hits your trim tab. They should be butt mated and the offset is (should be) there to center the front of the prop insert, hence the thrust washer (offset part) would drop down inside the plastic offset which it doesn't.

When you look at your last picture you should NOT see a gap between the mating surfaces of the plastic prop insert and the outer diameter surface of the thrust washer which I see in your picture.
So, either you have the wrong hub, or you need a special thrust washer for your application. Once you get that corrected, the prop can move forward on the shaft by whatever that offset is (on the thrust washer) and you should clear your trim tab.

HTH

Mark
 

Texasmark

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Re: Hustler prop hits trim tab - Mercruiser Alpha

Might look back at the catalog and recheck your model number and also look for any * that might take you off to a special note indicating the requirement for a special thrust washer. If so, they usually give you the OEM p/n for it.

Also, my Merc dealer torques these hubs to 90 ft-lbs. Folks on here suggest 100. Choice is yours, but they apparently are designed to run in a significant amount of compression.

A 2x4 against the antivent plate works well to hold the prop when you torque.

Mark
 

rparge

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Re: Hustler prop hits trim tab-Merc Alpha-Solved?

Re: Hustler prop hits trim tab-Merc Alpha-Solved?

Got a reply from Hustler, very prompt and courteous, that's nice to see.
They say that their hub is supposed to fit on top of the step on the thrust washer, and that the rake on these are much more than the stock units, and you have to replace the trim tab.

Quote:

"Yes, the propeller will strike the trim tab on Alpha One ...Reason being is the TP prop you purchased is a higher rake, more aggressive, and better performance propeller then your OEM aluminum. All performance props are constructed similarly. Mercury has made the replacement trim tab
(822777A1 or 76214AS) for its high rake design propellers. You only need to ask for 'high performance' trim tab from any Mercury dealer, they know what you talked about.

The fit on thrust washer is not the cause of the blade hitting trim tab. Our props are designed to fit against the flat surface instead of over the step."

So there you have it, sorry to raise the alarm, this is my first boat, and I wanted to be prepared in case of failure, so I 'm glad I discovered this on dry land instead of in the water stranded!

This is a great forum, again thanks for the help!

Cheers!
Rick
 

Texasmark

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Re: Hustler prop hits trim tab - Mercruiser Alpha

Well sir you said something that kinda blows that away in my mind.......yeah I know they designed and make the thing, they ought to know how it fits...so who am I to question that. Having been a design engineer for many years I know that errors occur and sometimes your product is down the road before it becomes obvious.

You mentioned that you had prop wobble at the front of the hub, unlike the OEM prop which had none.

If the thrust washer fit inside the hub lip, the thrust washer would be a stabilizing force to hold the hub in alignment, at least until it got torqued in place. As you know it's a ways back into the prop before you get to the spline, and there is clearance between the splines of the propshaft and prop, hence slop, hence wobble-potential for misalignment...............but what do I know.

I think I'd get her installed and torqued and with the boat on a trailer, lower unit vertical, I'd get on a concrete floor with a scale or other measuring device and rotate the prop 360 degrees checking for true running of the hub and the prop tips.

I've seen two of the tabs mentioned. One is just a short version of their regular one...leading edge moved back half the distance of the OEM (making it thinner in the fore-aft dimension) and the other I saw on here a few months ago where the tab actually was on an extender and was mounted behind the round part of the tab assy.....and it is stocked and sold by iboats. First gives you about an additional half inch clearance, the latter probably an inch.

My 2c.....which I get bashed for but what the heck..Life's too short.

Mark
 

Texasmark

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Re: Hustler prop hits trim tab - Mercruiser Alpha

Not ready to turn this loose yet.

If the thrust washer is designed to ride on top of the hub, then why is half the mating surface of the hub recessed and not flat (flush) to obtain maximum mating surface area for the 100 ft-lb prop nut torque?

Mark
 

rparge

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Re: Hustler prop hits trim tab - Mercruiser Alpha

Hi Mark,

All real good points, and I think I see where these folks are going with this. Instead of using the rear thrust washer, the front of the prop is designed to do this - the plate that goes on the front under the nut has got this crown, and when you tighten it up, this is where the prop is secured from any "yaw" motion.

IMG_1639.JPG


IMG_1644.JPG


This appears to make the unit one solid piece when you tighten up the nut. Also, the instructions said to tighten up to factory specs, which is 55 ft/lbs. I went 60. :)

Now all the pressure is at the end of the output shaft instead of near the housing. This makes me think that possibly it could be more prone to bending the output shaft, but who knows, I'm no engineer.

Cheers!
Rick
 

Ebb205

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Re: Hustler prop hits trim tab - Mercruiser Alpha

IMO,
The thrust washer will "press" the hub into the prop. The rear lock washer has an inner lip that will come in contact with inner hub. After you add the proper torque, the metal surface of the prop should come in contact with the thrust washer.

In the end, both washers will contact the hub and the metal of the prop, one big happy sandwich.
 

Texasmark

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Re: Hustler prop hits trim tab - Mercruiser Alpha

rparge, with prop wobble at the front, there is nothing to force the hub to center on the thrust washer, hence propshaft.

The pic you showed this time is just the locking ring for the prop nut lock tabs to lock into.

EBB 205, the only metal in this hub is a good inch down the length of the hub from the point where it butts up to the thrust washer.
-------------

This just seems like a honkey setup to me. Since I have one of these props, have examined it, thought through the design, installed it and ran it, I still feel that something is not right on your installation.

I'll leave this thread with this suggestion. When you run it, if you get any vibrations (before or after you strike a submerged object) you know where to look for the culprit.

Good Luck,

Mark
 

Ebb205

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Re: Hustler prop hits trim tab - Mercruiser Alpha

Ok, I see now...
the thrust washer is against the hub so all of the "power" transfers thru the hub into the prop. Hence, the "protection" if the prop hits something the hub will give before the shaft gets screwed ( in theory anyway).
 

Texasmark

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Re: Hustler prop hits trim tab - Mercruiser Alpha

I lied. I'm back.

No Ebb, that's a fluke also. The brass(bronze) spline of the hub is molded into the plastic (of the hub) with radial teeth extending outward into the plastic which grab the plastic (so that the brass and plastic interface doesn't slip). The prop has 4 (as I recall) tabs running lengthwise down it which fit into slots molded into the plastic........so that the plastic-prop interface doesn't slip.

So we have propshaft spline to prop hub brass spline to plastic to prop hub....all geared together and locked in place.

I guarantee you that if you hit something with this sucker the plastic is going to shear. A rubber hub slips and re-establishes it's grip. This sucker has no way to go but tear apart. Course a replacement hub is about $35 so if I were to run this prop or any like it, I'd have a spare on board.

But this is analogous to the old shear pin theory. Problem is when you sheared the pin, you were without power and if you were on the windward side of the riprap you were in deep doo do. With the rubber hub it slips, reengages and away you go. Did history repeat it'self?

Mark
 

Ebb205

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Re: Hustler prop hits trim tab - Mercruiser Alpha

I see now texas, thanks.

rparge, when you slide the prop onto the shaft, is there a gap between the lower unit housing and the prop? The prop should fit just barely inside of the housing like the OEM.

Also, how much of the propshaft splines are exposed on the nut side of the prop before installing the lockwasher - tab- and nut?

there should be some exposed splines for the lockwasher to "grab" onto.
 

rparge

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Re: Hustler prop hits trim tab - Mercruiser Alpha

I checked the gap between the front of the prop and the lower housing, and the OE and the Hustler look exactly the same, and yes, there are some exposed splines. See the photo above, you have to scroll a bit to the right to see that.

I took it out to the lake this weekend, and it ran great, 4800 WOT, it gets to plain quickly, and it was nice and smooth.

I replaced the trim tab with a blank unit as I have power steering, and it handled the same, no pull or anything.

Thanks for all the help, it made for a much more confident outing.

Cheers!
Rick
 

DaBobber

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I just had the same problem and used an angle grinder to shave off enough clearance on the trim tab to fit the propeller. Case closed. Easy peasy.
 
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