Xr4 An Xr6 Gearcase Question

[SAMMY CORLEY]

Is da xr4 an xr6 da same gearcase? da same size an are they both da same strenght wise?

Sammy in S.C.

[6Killer]

No, the XR4 is different, its much weaker. It has a very weak pinion bearing and a different drive shaft. For a HP motor, stay away from the XR4. Mercury replaced the XR4 with the XR6 case for a reason.........the XR6 is better!

6

[jeff dunn]

Sammy the xr4 is also 5/8 of an inch shorter than the xr6 from top of gearcase to the center of the prop shaft, but I agree its not as good as the xr6. Jeff

[fyremanbil]

Can a longer bearing be put in the xr4 case. I had a bearing fail in mine and take out the drive shaft.

[MTOLLEY]

what if ya use it as a race only case? will it grenade the first pass? mike t

[6Killer]

what if ya use it as a race only case? will it grenade the first pass? mike t

Anything is possible. If it lets go at WOT, the powerhead goes boom also. Its your money, you decide.

6

[j_martin]

Is there an early and a later version of the XR4 gearcase? I noticed an ad for a driveshaft for an XR6 or late model XR4 in the parts section.

If so, how do you tell the difference?

John

[corley1]

so i assume that a xr2 is the weakest of the 3

[The Big Al]

The only two parts that are different are the case itself and the drive shaft on the early production cases.
The cavetation plate on a XR4 was shorter. Later model production XR4 case have the same shaft as the XR6.
The second production XR4 and XR6 case had a longer cavatation plate and moved the trim tab back.

The first production XR4 case from the mounting surface to the prop shaft center line is 3/4 inch shorter, this accounts for the different drive shaft.

All the bearings are the same size.

Now the first production XR4 case factory installed bearing was week.
But can be replaced with the later model designed bearing of the same size used in the later model.

I have one of the first production XR4 cases new in the box. I thought they would interchange. Found later all the difference from Mercury.

Some using them for racing say as long as you never shift them under power they will last.

If the casting number is 1655-9572C, first production XR4 unit, this is located inside the top of the housing in the trim tab area as looking at the inside the housing removed from engine.
The weak link in the housing is the carrier Assembly and the spanner nut working loose. On both XR4 & XR6

Rumors of giving the gears more clearance is wrong, and will cause the pinion to break, and will come out the side of the case.

Al

[pyro]

Corley, the '85 thru '87 XR2 gearcase is not unique. It's pretty much a standard-size, 2:1 "Alpha" case.

[MTOLLEY]

thanks! ill look at the case on monday when i get back to da shop. its off a 150 xr4 early ninties. last of the 2.4's. i believe the motor to be a 2.5 block with 3.375 sleeves in it. it has the dowels for the heads like 2.5's. mt

[The Big Al]

so i assume that a xr2 is the weakest of the 3

Nothing special for the XR2, had the same case as standard 2.1 gears found on other 2.0 V6's

Al

[j_martin]

AL
You da man!!!!

Thanks

[Rodney Nance]

Call Del at Nichols Outboard. He built the one we ran for years without a problem. There are a couple of tricks to them. 423-451-0125

[SAMMY CORLEY]

I'll call him an I appreciate ya help.


Sammy

[jphii]

Call Del at Nichols Outboard. He built the one we ran for years without a problem. There are a couple of tricks to them. 423-451-0125

Race case?

[MTOLLEY]

the casting number is 1655-9572C, first production XR4 unit, this is located inside the top of the housing in the trim tab area as looking at the inside the housing removed from engine.


this the number in the housing ive got. al, do you happen to have a part number for the better bearing? thanks mt

[SAMMY CORLEY]

Yea they raced a Q-Master a few years back.


Sammy in S.C.

[The Big Al]

the casting number is 1655-9572C, first production XR4 unit, this is located inside the top of the housing in the trim tab area as looking at the inside the housing removed from engine.


this the number in the housing ive got. al, do you happen to have a part number for the better bearing? thanks mt

<TABLE cellPadding=1 border=1><TBODY><TR><TD align=right bgColor=#ffffff>16</TD><TD align=left bgColor=#ffffff>31-36387A1 (http://javascript<b></b>:showPicture('showSpecialPicture.asp?pn=36387A1'))</TD><TD align=left bgColor=#ffffff>--ROLLER BEARING, DRIVE SHAFT (click here) (http://javascript<b></b>:open_window())</TD><TD align=left bgColor=#ffffff></TD><TD align=left bgColor=#ffffff></TD><TD align=right bgColor=#ffffff>$45.50</TD><TD align=right bgColor=#00ccff>$43.23</TD><TD align=right bgColor=#ffffff>1</TD></TR></TBODY></TABLE>


I Have a brand new housing for that lower if you ever need it. (virgin never run)

[MTOLLEY]

thanks al! ill get one on the way.

[jphii]

Yea they raced a Q-Master a few years back.


Sammy in S.C.

Thanks Sammy. I'm hoping we get a rules change in Pro Carb so I can run an XR6 case next year. I've started lookin already.

[MTOLLEY]

<TABLE cellPadding=1 border=1><TBODY><TR><TD align=right bgColor=#ffffff>16</TD><TD align=left bgColor=#ffffff>31-36387A1 (http://javascript<b></b>:showPicture('showSpecialPicture.asp?pn=36387A1'))</TD><TD align=left bgColor=#ffffff>--ROLLER BEARING, DRIVE SHAFT (click here) (http://javascript<b></b>:open_window())</TD><TD align=left bgColor=#ffffff></TD><TD align=left bgColor=#ffffff></TD><TD align=right bgColor=#ffffff>$45.50</TD><TD align=right bgColor=#00ccff>$43.23</TD><TD align=right bgColor=#ffffff>1</TD></TR></TBODY></TABLE>


I Have a brand new housing for that lower if you ever need it. (virgin never run)
al , ive got that bearing. that is the upper bearing. do they have a better bottom bearing(directly above the pinion gear)? according to del at nichols, this one (bearing) wont last long. the one i got has lots of tiny needles and i need one that has larger needles if its available. thanks mt

[j_martin]

The weak link in the housing is the carrier Assembly and the spanner nut working loose. On both XR4 & XR6

What's the symptom of this? What is normal end play on the propeller shaft?

Thanks
John