Need held identifing xr6 gear case

[97 TWISTER]

Try to figure out how to tell by looking. It has 4 1/4" housing 4 hole water intake and the only #'s are 1 674 814247C Thanks in advance

[outasite]

Have to wait and see,but I think the C gives it the bigger pinion bearing.

[transomstand]

XR-6 has the longer cavitation plate.

[patchesII]

That's the casting number on an XR6 case I have. Do you want to sell it

[97 TWISTER]

That's the casting number on an XR6 case I have. Do you want to sell it

Only if I can't figure out how to put it back together lol. It's just the case. Thanks for input

[tlwjkw]

That's the casting number on an XR6 case I have. Do you want to sell it

bobby may still have one or two.... since i gave all this stuff up!

[DRM007]

I'm looking for xr6 with ratio 178 to 1 if any buddy knows....

[CircleHook]

What is difference length? just want to learn sumpin..

[DRM007]

Sorry I don't no much about this gear case other then it's suppose to be the one to get for my drag boat...

[patchesII]

What is difference length? just want to learn sumpin..

Diameter of the case is the big difference. XR6 cases are 4.25" diameter as opposed to the 4.75" of a standard Mercury case

[Capt.Insane-o]

572 is the xr4 case, 247 is the xr6

[David]

It's the case to get if you don't care about longevity.

[Glastron1987]

The number on my XR4 4 1/4" 1.78:1 LU has the number 1655 9572C cast/stamped into it. Not sure if that helps.

[CircleHook]

Diameter of the case is the big difference. XR6 cases are 4.25" diameter as opposed to the 4.75" of a standard Mercury case
Does the diameter difference apply up into 2000 up stuff? What about mid '90s ? I currently have a 2004 XR6 and I am pretty sure it has same diameter case as every other 2.0 and 2.5 merc I have owned- .. same props fit. Not arguing- just learning.

[Glastron1987]

This is my understating about those lower units. It may not be exact, but maybe close:

Starting in 1988 the XR4 motor was offered with a choice of either the 4.25” or the standard 4.75” lower unit. This ran through about 1991.
Then the XR6 came out. I believe it, too, was offered with a 4.25” or standard 4.75” lower unit. But after about 2 years and thereafter only was offered with the standard 4.75” lower unit.

The XR4 4.25” lower unit and the XR6 4.25” lower unit have the same diameter, and ratio of 1.78:1, whereas the standard lower unit (4.75”) has a ratio of 1.87:1.

The XR4 4.25” lower unit does not have a reputation for being highly durable, as some guys seem to have blown them usually when surfacing them. Many have had no problem with them, including me. I did however switch to the standard lower unit a few years ago because I felt there was a better selection of props that would provide better bite for skiing.

There may be a minor difference between the XR4 4.25” and the XR6 4.25” as it appears the part number may be different. The XR6 one may have some slightly different parts in it that may make it more durable. I thought someone may have mentioned that. If that is true, then that would be a great lower unit to have as the 4.25” size does make them a little faster than the standard.

After they stopped offering the 4.25” lower unit on the XR6, maybe around 1993, I do not think they offered them ever again.

[David]

I don't think the XR4 came with anything but the small case. The XR6 came with both.

i blew up 3 XR4 gearcases with a lightly modified XR4 engine. Some surfacing probably did the damage.

[Glastron1987]

I'm pretty sure the dealer offered me either lower unit when I purchased my XR4 towards the end of 1987. I remember having to make a choice. That’s what I’m going by.

[bigbluechevy454]

The xr6 the prop shaft is in the same place in relation ship to the cavitation plate. Xr 4 is 1” closer to cavation plate. As in if u put xr 4 on your boat the prop shaft height will be up a 1”. Both are fragile in stock form

[bcrick]

I've only seen one of these small V6 gearcases . Think it was off a xr4 didn't see the motor . The guts looked the same as what an inline 6 has with a 1.78 ratio .

[Glastron1987]

Wow that's the first time I’ve heard that there was a difference in the dimension between the plate and shaft between the XR4 and XR6. That’s good to know. Now how would someone beef one of those up from stock?

[Capt.Insane-o]

Custom bearing carrier helps out a ton with the thicker webbing and roller bearing for reverse. I set mine up tight and run a lighter oil changing it every other weekend. The motor it was on had most of the water bypassed but the plate dumps were piped right down through the exhaust to the bearing carrier.

Speaking of which the particular carrier that is in it has very little area for exhaust to pass so if you run a fishing mid it has to be relieved in other areas. Keeping the rpm spikes to a minimum in rough water along with never shifting while running. I ran a xr4 lower under a mild 200 on my HST for quite awhile with no issues and my xr6 case has been under some big rpm without issue but the thin skeg worried me for the running I do

[Glastron1987]

One year I stored my boat in someone's barn and they moved the boat and broke the skeg on my XR4 unit. I had it welded and it continued to work well for me until I decided to replace it with a standard one for better prop options. Still have the lower unit in my basement collecting dust. With its original (weak) parts and a welded skeg, I'm not sure if it will ever find use again. Here's a picture for entertainment.
391879

[j_martin]

My XR4 skeg has a little notch broken off. Had it repaired several times. Breaks at the weld if it's touched. Has a little prop torque in the steering, but with NFB steering, it's isn't a big deal.

I had it X-rayed one time. Pretty chitty metal. X-ray looks like it has measles.

[Capt.Insane-o]

Took the band saw to a busted up sportmaster, I wasn't impressed lol