Ok, I need a serious discussion on a possible Pro-drive Frame mod and need to see the Pro's and Con's of it.

Anyone who has had or does have a PD knows that changing the clutch is a PITA!! I recently burnt up mine and have purchased the Extreme duty clutch to give it a try. After looking at the clutch and seeing possibilities of other options, I stumbled across something that might make the PD guys headach a little less painful. face it, the main problem with changing the clutch on a PD is pulling the block and having and using a hoist of some sort. So I have a possible solution that will allow the PD clutch to be removed without pulling the power head.

The clutch is approx. 2-2.5" tall and slides on the crankshaft. the offset bushing bottoms out on the crankshaft, followed by the clutch, then the washer and bolt to hold the clutch to the crankshaft. The the spline adapter is bolted to the clutch assembly by 4 Allen head screw. Then the entire assembly is lowered onto the "male" spline shaft. If the clutch is approx. 2-2.5" tall or however tall it is, why can't a spacer be made and placed between the clutch and the "female" spline adapter?

PD frame Mod.jpg

Look at the above pic. This is an older picture of my clutch assembly before I added hydro reverse, but the hydro system has no bearing on what I want to do. The clutch will be mounted exactly the same. Standoff bushing, clutch, washer and bolt. The spacer will be slightly taller than the clutch as a whole. The spacer will then bolt to the clutch the same way the "female" adapter would. The bottom of the spacer would then bolt to the "female" spline adapter. Thus making it a RIGID Coupling. If the clutch were to ever go out, unbolt the spacer from the clutch and the female spline adapter and remove it. This will allow the female spline adapter to stay in place as well as the entire block and assembly. The space provided by the "spacer" would allow the bolt that holds the clutch on to be accessed and loosened. The clutch could then slide off the crankshaft into the void and be removed. To replace the clutch, simply place the new clutch in the void area and slide on the crankshaft. Torque the clutch bolt and reinstall the spacer.

Now in doing this, the tall bolts would have to be replaced with longer ones and aluminum spacers would have to be longer also. The engine would sit up approx. 2-2.5" higher which is no problem. It will have no effect on the reverse system (manual or hydro) because the gear is below the "female" adapter.

Now for the discussion:

One advantage of this that I see, is for those riding in very remote areas or long rides from the landing, this can be changed in the field with minimal tools required. I for one had my clutch burn up 16 miles from the landing to which I was towed in and destroyed my hull. I could keep an older clutch in the "parts bin" in my hull with other crap such as switches, tools, lights, etc. This could atleast allow you to limp home rather than sit and wait for help. Now StuAlaska runs a GD, but in his situation, being in the remote areas, this would be a huge advantage. You never know when the clutch will go nor where it will go, but this sure could help.

On the other side, by spacing the engine plate and other plate further apart approx. 2-2.5", you must insure that the "frame work" stays rigid and doesn't flex or move. this will put extra stress on the clutch, spacer and female adapter. Larger diameter bolts can be used as well as other means to "stiffen" the framework to allow it to work.

So, I' trying to initiate some deep thought discussion because this is a definite possibility that I might try considering these shitty clutches and lack there of a gearbox.

HELL YEAH! Now we jus need a gearbox to throw away that POS clutch!

It may not sound like much and it may not be much...but, it's one more thing for the power head to turn.

If you go with taller spacers, strengthen them with thicker wall thickness to regain strength lost the ought lengthening...and same could be said about the bolting...although, I doubt if the bolts are seeing those kinds of stress moments.

Other than the added height...I don't see any cons...other than, you have to do it. LOL

I like the idea. Will the spacers being longer make them weaker as far as "twist" loading?

Blue beat me to the point

From what I see as far as torsional load, none. We have 1000 hp motors turning these tiny rigid couplings here at Dow.

And yes try, that was my only other addition was bigger aluminum pipe spacers (wall thickness). These engines won't produce near the torque required to torsion shear a 2" diameter SS spacer. A 3/4" prop shaft, yes due to hitting and creating a huge stopping force. But not a 2" diameter "shaft"

And if need be, I'll make a stress bracket that will bolt both plates together thus taking the stress off the 1/2" bolts that sandwich it.

I'm not as concerned with the side loading as I am with having to pull a clutch on the water!
What would I spend my time, money and effort on? A temporary device that would engage the clutch disc or lock the clutch allowing you limp back to the ramp.

No. 8 bolts that remove a spacer that allows you a much easier way to change the clutch. Changing it I. The field is nothing unless you drop 1 of the 8 bolts. No temp fix, permanent.

How about replacing the aluminum spacers with stainless?


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I really don't think there is much side to side load. More torsional. But I'm open to all options. If it catches on, so be it. I'm just thinking outside the box for an easier way to change a PD clutch. All the horizontal locks stay bolted to the frame.

I'm talking about when the clutch gets seized on the shaft.
You would also have to tap threads in the spline adapter. All very doable. I say a temporary device because most people won't want to drop the coin on a spare clutch to carry in their boat. Some fail at 50hrs or if you're lucky like DA, you get a 1000hrs out of one.
A temporary device that cost less than $50 bucks that could be installed in 5 minutes to get me back to the ramp, and takes up a lot less room in my boxes sounds more appealing to me. Patent it, then sell them to Prodrive and their existing customers. Just my .02 good luck man.

I like the temporary idea. Just something quick to lock you in forward.

There's no possible way to bypass a broken clutch due to the stationary bell housing on the top without removing the bottom and connecting the shaft. This idea is viable though just because you can change the clutch without pulling the power head. It would still be shorter than a GTR. Haha

Banded, this is brilliant. Sell it!

What about bolts threaded horizontally through the coupler/spacer/clutch?

Moving the cav plate up and away from the prop for post Gen II was my idea. They didn't go for removing it completely. LOL

I've asked a few people and tried searching and I can not figure out what Condideration means.

Conundrumly consideration ??

H finn

That shit would shatter like an egg if you did that.