Drive saver for direct drive A4

[CalebD]

I bought a lightly used Drive Saver for a direct drive A4 motor for ~ $100 from another boat owner over a year ago. With our new shaft installed this spring I find I do not have any use for it so it is available to whoever offers a reasonable amount for it. Brand new drive saver units for the A4 cost about $225 + shipping.
I comes with an assortment of extra bolts you can see in the pics below.

[CalebD]

Bump.

Still for sale.

[keithems]

what does it do?

[ILikeRust]

It's a slightly flexible coupling that allows for very slight misalignments between the engine output shaft and the prop shaft and absorbs vibrations - supposedly helps reduce strain and stress on the entire drivetrain, minimizing wear on bearings and such and making the drive train smoother and quiter.

[CalebD]

Drive saver for A4 direct drive

Since you asked, here is what the Globe Composite company claims the "Drive Saver" will do for you boat: http://www.globecomposite.com/pages/products_drivesaver

Since I have never tried this unit out on my boat I can't stand by any of the claims of the company. It sounds like a good idea on paper.

Nowhere in their marketing literature does it say that it will take up the slop from a very slight mis-alignment between the engine and shaft - that I could find. What Bill T. described is what I bet they want you to think.

[sastanley]

That thing mighta helped the other member on this forum with the short drive shaft that had his prop hub rubbing on the cutless bearing until he physically moved the engine aft...mighta extended the drive shaft just enough to clear without the hassle he went thru to move the engine.

Who was that?

[keithems]

I

think i should go for it?

[hanleyclifford]

I think the greatest single advantage of this product on the A4 is the electrochemical isolation of engine and drive train. If I had the room I would use it for that reason alone.

[keithems]

not sure what that means

remember i'm in fresh water here

[sastanley]

keithems,

you've already gone thru the hassle of moving your engine..

[keithems]

maybe not enough

[CalebD]

Original intentions

When I bought this used Drive Saver my original intention was to use it to extend my shaft by approx. 3/4" as I had a very limited space to attach a collar zinc between my prop and cutless bearing. It would have worked fine for just that but I ended up getting a new, slightly longer (3/4" longer) shaft as our old shaft was scored pretty badly.

I'm not convinced that there are any benefits from electrochemically isolating the shaft from the engine. The way I see it is if my boat were struck by lightning, the lightning might find it's way to the engine and the shaft provides a good connection to the water which is the 'ground' it seeks. In this scenario I'm sure that much of the engine would be toast (alternator, ignition etc.) which would leave me with other problems instead of being dead from side flashes.

The idea that the Drive Saver absorbs some vibration is appealing but this is not the reason I bought it.
If you need to extend your shaft approx. 3/4" then this unit should do that.

[hanleyclifford]

not sure what that means

remember i'm in fresh water here

There are still sufficient ions in "fresh" water to permit a galvanic cell. This is not related to a lightening strike which is a separate issue, but rather to the steady theft of electrons from the engine by the more noble shaft and prop. The prop or shaft zinc mitigates the problem but does not eliminate it.

[keithems]

i still don't know what u mean

do you mean that this would cause the engine to rust?

i've never had a zinc on my shaft -- prop is brass -- i remove it every winter and soak it in vinegar for a few days -- looks like new -- so i assume that's goo d enough -- but if you're saying the engine is rusting also, maybe it's not?

[ILikeRust]

Your prop almost certainly is bronze, not brass. Just quibbling that minor point...