Prop Shaft Key

[Esco]

I've got a question about the brass key that aligns the prop on the drive shaft. The boat is a 1998 Sunsetter VLX.

The key that was on there when I took the prop off looks like it may have been damaged also. Is the key supposed to be square on the sides? This key has the "top" corners mitered at 45 degrees. There is also a score mark down both sides of the key. Are these score marks supposed to be there, or is the key damaged? If it is damaged, can it be replaced with a square-edged key, or does it have to be an exact replacement? Thanks.

[SacRiverRat]

I have never seen a "new" key... but mine isn't sqare either.. it has a line down both sides.

Does it hold the prop in place (from spinning on the shaft) ok, or does it feel sloppy?

[Esco]

Honestly, I haven't run the boat since the prop damage occurred. It looks like the old key will still work fine, it's just a tad worn. I wanted to just replace it with a readily available brass key stock, but have since gotten in contact with the dealer to order a new key along with another part that I need anyway. Hopefully the old key will work okay until the new one comes in. I'll find out tonight.

My main concern were the lines on the sides of the key. I thought they were from damage, but it seems that they might have always been there.

[BlastRlxi]

The key is proably rounded off to make it easier to put in. As long as the keyway on the shaft is okay, you should be fine.

[Gordo]

As long as the key fits snugly in the keyshaft and holds the prop without any "slop", you are good to go. Its always a good idea to keep a spare key just in case you loose one. They are not the easiest things to find.

[LS-One]

The angled sides lay in the shaft keyway. I do not know why but that was how I was instructed with my first bu in 1991 by a plant emloyee.

[Esco]

Thanks for the replies. This site is definitely the go-to place for Malibu boat info. Both of the questions I've had recently as a new Malibu owner have been answered promptly and with a plethora of knowledge.

I thought that the shaft key could be found at any good hardware store, but once I started looking, found that to be untrue. I did the safe thing and ordered the Malibu part from the dealer. Thanks again for all of the help.

[mrothwell]

Thanks for the replies. This site is definitely the go-to place for Malibu boat info. Both of the questions I've had recently as a new Malibu owner have been answered promptly and with a plethora of knowledge.

I thought that the shaft key could be found at any good hardware store, but once I started looking, found that to be untrue. I did the safe thing and ordered the Malibu part from the dealer. Thanks again for all of the help.

Yes there is copious amounts of knowledge here.

Sorry, just couldn't help myself.

Esco - welcome to the family.

[Ronnie]

The lines on the sides of the key are where the edges of the shaft and prop are hitting the key and trying to shear it in half. IMO this is why you need to make sure to replace it with a brass key instead of a stainless one. The brass one will shear causing less damage to the key ways than a hard stainless one would. The stainless keys are easier to find than the brass most of the time. Your dealer should be able to get you the brass key.

Tip: Order an extra one to keep with your spare prop.

[woody]

The lines on the sides of the key are where the edges of the shaft and prop are hitting the key and trying to shear it in half. IMO this is why you need to make sure to replace it with a brass key instead of a stainless one. The brass one will shear causing less damage to the key ways than a hard stainless one would. The stainless keys are easier to find than the brass most of the time. Your dealer should be able to get you the brass key.

Tip: Order an extra one to keep with your spare prop.

Ronnie is right on the money. The brass key is a shear point for the prop and shaft.

Also you buy the brass key way stock at Home Depot a cheaper than what the dealer will sell it to your for.

[BillFooter]

I can personally attest that if you hit something hard enough the key stock will split. Mine was brass and it split. If you hit something hard enough to split the key stock, believe me you got problems that will cost a couple thousand $$$ to fix.

[BlastRlxi]

I can personally attest that if you hit something hard enough the key stock will split. Mine was brass and it split. If you hit something hard enough to split the key stock, believe me you got problems that will cost a couple thousand $$$ to fix.

I agree. The brass key, while more likely to break than a SS one, is different than a shear pin and will not break until a significant amount of force is acted on it.

[Ronnie]

I sheared a key last year. Cost me $60 to fix the prop. NO damage to the strut or shaft since the brass key took the beating and split. It was tough to get the prop off though.

[1FootDan]

Can you post a picture? I was a gearbox mechanic/gear cutter for 4 years and have seen my share of damaged keys. If the key is grooved on both sides, it may just be that your prop nut wasn't tight enought and when shifting from reverse to forward, the prop moved on the shaft. When tightning your prop nut, aborb all the slack (backlash) in the direction you are tighning (clockwise). Otherwise, your nut will losen and the prop will be loose on the shaft which may damage your key.

[Cdoogles]

I sheared a key last year. Cost me $60 to fix the prop. NO damage to the strut or shaft since the brass key took the beating and split. It was tough to get the prop off though.

I sheared a key last week. Didn't hit too hard... just bent two blades on the prop. However, I had the same experience with the prop being a total pain to remove!!!

Just got my spare prop back on last night... haven't water tested but I'm hoping nothing else was damaged. .....

[skibreeze]

I sheared a key last week. Didn't hit too hard... just bent two blades on the prop. However, I had the same experience with the prop being a total pain to remove!!!

Just got my spare prop back on last night... haven't water tested but I'm hoping nothing else was damaged. .....

I would have put a dial indicator on the shaft, more than likely it is bent also.

[skiguy]

Can anyone tell me what length the key needs to be for a '98 Sunsetter? The stock key I got from the prop shop was too long so I just used the old key when I changed my prop but I would like to use the new one that is not worn.