Woe's since installing S/S prop

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Hi everyone,

I have a Mercruiser 1.7 (120HP) Turbo-Diesel on my sports cuddy with an Alpha 1 Gen II leg

It came as standard with a 14 x 23 aluminium prop, but was over-revving, so I upgraded to a 14.25 x 24 stainless steel prop. I fitted it up nice and tight. Nothing is loose, there is no play on the spline. The prop rotates freely and doesnt come in contact with any part of the leg

When I put the engine into gear, there is a very loud 'thumping' noise until I hit 1200RPM. Once I hit this RPM it stops. This did not happen with the aluminium prop. I am worried that I might be doing damage to my gearbox. Has anyone had anything similar happen to them? The noise is definately coming from the leg, because the noise goes when I put the engine into neutral. Could it be the extra load thats making the noise?

 

[tommays]

Re: Woe's since installing S/S prop

If you are useing and XHS hub there is Info in the prop forum about useing a higher torque now to stop some prop noises


Tommays

 

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Re: Woe's since installing S/S prop

Thanks for that, i'll take a look. The hub kit on my aluminium prop was a Flo-Torq

The one on the stainles steel (the noisy one) is the type with the plastic around the perimeter (Like on Yamaha outboards, if that makes any sense). This actually worried me, as I needed to use a spacer on the nut end of the spline, but it seems to fit and is not slipping.

Do you know is this doing damage or is the noise just an annoyance that I can put up with?

 

[Reel Poor]

Re: Woe's since installing S/S prop

With thee engine off and turning the prop by hand, does it make the noise?

Remove the prop, start engine and place in gear,,,,,Is the noise present?

 

[tommays]

Re: Woe's since installing S/S prop

C&P


Some advice from Mercury Marine here...
As some have experienced a "clunking" noise when using this type of hub system, let it be noted that the torque values are much higher for these.
Where the engine manual calls for 55ftlbs of torque for normal hub props, the XHS and Flo-torq II require 100ftlbs of torque.
This may be some of the issues of noise at Idle that some of us have had. It has to smash into the plastic insert pretty hard to hold solid.
Hope this info helps some...


---
Kenny
When you run a 'RUDE, the only thing you hear is the roar of finely-tuned excuses in your wake.


Tommays

 

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Re: Woe's since installing S/S prop

The prop moves freely
If I take the prop off and put it in gear, it does not make this noise. Also, there is NO NOISE when I use the alum prop, the noise ONLY incures with the stainless steel prop, until I go over 1200RPM. After 1200RPM the noise goes away

 

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Re: Woe's since installing S/S prop

Thanks a million for that, things are becoming more clear now!

So am I actually doing any damage? I have the nut tightened as tight as I can (Didnt use a torque wrench), my local marine mechanic just said to tighten it as much as I can by hand, it will be fine once the locknut is in good working order

-Edit- Also, is the hub kit on the S/S prop the 'XHS' type... Sorry for the stupid questions, I know very little about the hub kits. Here is a link to the prop: http://url.ie/1ud

Here is the hub kit (same type) that was on the alum prop: http://url.ie/1ue

Could I get rid of the clunking noise by torquing the nut on the S/S to 100ftlbs?

 

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Re: Woe's since installing S/S prop

I just had a look at the alum prop there, and I reckon I may b ebale to swap over hubs.

Can hubs be re-used. Also, whats the procedure for removing them from props? Sorry for all the questions, im a total noob!

 

[RubberFrog]

Re: Woe's since installing S/S prop

Just torque it to 100 lbs and see what happens.

 

[Tail_Gunner]

Re: Woe's since installing S/S prop

:}

 

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Re: Woe's since installing S/S prop

Here is a picture of the prop I have on it at the moment. Can anyone identify the hub kit in it? It's the type with the rubber around it. Can this be removed? Also, there is nothing between the prop and the gearcase on the spline. I just removed the old prop and put on the new one. Should there be a thrust washer there?

 

[tommays]

Re: Woe's since installing S/S prop

Yes an it needs to be the correct ONE for the prop brand AND a merc drive


Tommays

 

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Re: Woe's since installing S/S prop

As you can see from the eBay auction I bought it from: http://url.ie/1ul

The only description I can see is a "Mercury Rampage" ... I can't seem to find this model on the Mercury website?

I hay have found a solution, I'm going to get a spacer made up and torque down the nut to 100ftlbs, ill keep ye guys updated!

 

[Reel Poor]

Re: Woe's since installing S/S prop

Just any spacer won't work. It has to be correct and fit the tapered section of the shaft and set the prop to the proper distance away from the drive carrier housing. Only the one fitted for that particular prop and an Alpha drive will work.

Check with your local Mercruiser dealer or a prop shop.

 

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Re: Woe's since installing S/S prop

OK, thanks for the good advise, im going to bring the prop down to the local marine mechanic and see if he has any hub kit's that will fit

 

[Reel Poor]

Re: Woe's since installing S/S prop

I don't think that prop takes a hub kit. It looks like a press in rubber mounted spline sleeve.

Your origional prop should have had a spacer used with it. Maybe it's stuck to the aluminum prop. Take the origional prop with you also.

Should look simular to this one. Large washer (approximately 1/4 inch thick), tapered center, and stepped outter edge. Could be stainless or bronze.

 

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Re: Woe's since installing S/S prop

I'm going to take a look at my old prop now when I go back down the boat club.

Are you saying that I can't put a hub kit onto my new prop? It fits onto the Alpha spline, but there was still some of the sline visible when the propeller was fully inserted onto the spline. To compensate for this, I used a spare thrust washer (Which fit nice and snug, as if it were meant for it) on top and tightened the nut down. Could I be doing damage? If you see a picture of the rear of the prop below, you'll see that a thrust washer would not have fit on the inside, between the gearcase and back of the prop

 

[tommays]

Re: Woe's since installing S/S prop

Yes if the prop is not spaced correctly it will rub on the gear case

If the standard merc hardware does not fit correctly on the end of the prop and you need EXTRA parts to tighten it SOMETHING is wrong


Tommays

 

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Re: Woe's since installing S/S prop

Just to let you know, I checked the rear of the prop and there was a thrust washer in place like you mentioned.

I got a spacer and re-tightened the nut. The noise went! However, it appeared a few minutes later, so im guessing that it managed to loosen?

I think it's time to put this prop up for sale and go shopping again!