150 XR2 XR4 XR6 Differences

[27739]

I'm looking at buying a used boat with a 1991 150 XR4 Merc. Please help educate me as to what the XR2, XR4, XR6 designations mean on the late 80's and 1990's model Merc 150's.

Thanks.

Terry

 

[Dhadley]

Re: 150 XR2 XR4 XR6 Differences

An XRI is a 2.5 liter EFI V6.

An XR2 is a 2 liter V6.

An XR4 is a 2.4 liter V6.

An XR6 is a 2.5 liter V6.

 

[WillyBWright]

Re: 150 XR2 XR4 XR6 Differences

I believe the XR-2 had a smaller gearcase and used a smaller prop as well. But it pushed the limit on the gears and a lot of them grenaded. It was a bit faster because there was less gearcase drag due to it's smaller size, but then the larger blocks more than made up for that.

 

[05GlastronSX]

Re: 150 XR2 XR4 XR6 Differences

i have the last of the 150 xr6 model years (2005) on a 17ft glastron and i absolutely love it. I could not be more happier. I truly feel that this engine is underrated in power. If anything, it is a very strong 150. It is a 2.5 liter, 1.87:1 gear case, and it is pushing a 21 P prop and the thing could not be more reliable. I top out at about 55 +/- a few depending on load. I change it with hi performance merc gear lube for the winterization and everything has been great so far. Granted yours is 14 years older than mine, but i do believe that the XR4 that you are looking at will be a solid engine.

 

[j_martin]

Re: 150 XR2 XR4 XR6 Differences

I have a 1988 150 XR4. It has the smaller 4in gearcase and 1.78 gears. I measured the gears cause I didn't know what to believe.

I would worry about the gearcase if I modded the motor to high hp and rpm, but in the 6000 rpm 160-170 this motor runs stock or slightly modded, it's fine. It's a cam shift type 2 with a threaded case nut, so it seems to be an odd duck. If you keep up on the maintenance, especially the lube and linkage adjustment, (cam 2 is noted for wearing out the cam follower thus going out of adjustment.)