1997 GTX Counterbalance Shaft Gear Index

[yrn2fly]

Hello,

Viewed these forums often & this is my first post. I recently sold my GSX and picked up a 97' GTX 787 that is pretty clean albeit with the engine in a box. While in the process of blasting & alodining the bottom end & opted to replace all of the relevant seals.

To do this on a counterbalance shaft requires that the gear/weight combo be pressed off, which I did on my press. But to my surprise there is no indexing mark, no key, etc. Now I'm wondering how I can index the gear/weight back onto the shaft. Is there a reference point?

Thanks!

M Randolph
Encinitas, CA
97' GTX
95' Bayliner 1950

 

[ski-d00]

No, there's no reference point on the shaft since it is symetric and continuous. The only mark on the entire system are the marks on the gear that get aligned with the crank gear on reassembly. The only reference is that the end weights/gear are in the proper position with respect to each other when pressed on.

 

[yrn2fly]

Thanks ski-d00. So it's looks like I'd have to go through the whole business of aligning as per the manual & then making a few trial runs to get the gear dead on before I press it on... as in the manual page attached.

I'm thinking it'd be easier to just get a new cb shaft from SBT or similar since it seems that the shaft seals are not sold individually anyway and one from SBT is like $59.

Thanks again!

M Randolph
Encinitas, CA
97' GTX
95' Bayliner 1950

 

[ski-d00]

it's not hard to align, you'll probably get it your first try. just do what the manual tells you. many times when rebuilding a motor the cb shaft is pristine as well as the seals and it can just be reused, if your seals looks good and are still flexible they should be fine. you can opt for an sbt reman one for peace of mind but probably not necessary if all your components are good.

 

[yrn2fly]

Yea,

In looking over the manual I've decided that I'm going to do it myself. I'll stick the #18 gear assy in the oven I have at my 2nd job & do the alignment(s) with it hot so that it wont gall the shaft. Once I get my mark, I'll slide on the seals & then press it on. It just seems a little weird that a rotational part would have no keyway & only use an interference fit but... hey, it's been working in this case since 1997.

And I think the seals are in fact available...

From what I can tell they are P/N 420930392 (old # 290930390) and are about $8.00 each. I found the description on this page..

http://www.angelfire.com/oh/theboatguy/enginecomponents.html

which I hope is accurate.

Thanks for the advice ski-d00!

M Randolph
Encinitas, CA
97' GTX
95' Bayliner 1950

 

[diesel04]

oil seals...

could you jsut go to a bearing place and get them to sizeup the seal and get new one?? going throught the same process....

 

[PWCdoc]

The method described is how to install the CB shaft, not how to properly reinstall the gear you removed. It must be installed with the counterweights 180 degrees from the opposite counterweight.

 

[ski-d00]

You are right about the second half of the page, the first part of the page ym2fly posted tells how to align the gears, it basically is just using the case half to aid in alignment so they are exactly 180 degrees apart like you said.

 

[PWCdoc]

Just wanted to make sure you got it right. Otherwise it'd vibrate like heck.

 

[yrn2fly]

OIC. Yes the weights did appear to be 180 degrees out, but since there are no index marks the only way to make sure they are aligned precisely would be to use the case alignment method. My case had some very light fretting so once I'm done lapping it I'll drop in the shaft & attempt to fit the gear/weight in alignment with the case (should be fun if it turns in to a trial & error routine). Should also be fun since there is no shoulder to limit depth of the interference fit of the gear (as in how far onto the shaft to press it), but I think my initial depth measurement should put it pretty close.

Thanks for the replies though. It was good validation to not have to guess about orientation of each gear to the other.

M Randolph
Encinitas, CA
97' GTX
95' Bayliner 1950

 

[yrn2fly]

Diesel04,

As far as I know I think one could do a seal match, but it'd be a pain given the sheer number of seals available. And the type of material, if they are metal impregnated or spring retained (internally), etc. In my experience (lots of vehicle restorations, boat resto's & aircraft engine o/hauls) there are likely a boatload (no pun) of seals to xref to.

globalspec has a oil seals cross reference but you'd need to know more than just seadoo cshaft seal. In the end I'd just get the seals AND the end bearing listed for the shaft. My bearing was in good shape but after a little heat and the 20 ton press doing it's thing, I wouldn't reuse it (especially with a plastic cage).

Just my 2 c

M Randolph
Encinitas, CA
97' GTX
95' Bayliner 1950

 

[diesel04]

got bearings off

yrn3fly, thanks for the reply.

i got the bearings off. i checked visually the counterweight and gear, it appears they are off a few degrees. wondering if anyone has measurements on how far to push the gear and bearings back on, as there is small lines "scratched" on the shaft behind gear and counterwight that it doesnt cover up, so i was wondering if it hasn't been pushed on far enough.

thanks alot

 

[diesel04]

off a bit?

hey guys, checkd the counterbalance in my crank, and it seems they are correct, but then flip to other side of crank(still in bottom) they are off a few degrees. prolly out about 1/4'' inch. does this make sense, also, should i stay with the open bearing or can i run sealed. thanks