Mercury XS motors

[2us70]

The gear ratios were different but I don't recall the numbers. The sharing of gearcases really helped the 500s a lot. The gear ratio in the 500s was lowered to allow both the 650 and the 500 to run the same props. I think the strut was maybe a little deeper as well to accommodate the bigger diameter 650 props. When I sold my E Production boat I kept the Bobby Soles built props and ran them on my 500 in SD with pretty good results.

[FUJIMO]

...40 & 402 2 cylinder.....2.1 gear ratio. 40/45/50/500 4 cylinder.....2.1 gear ratio. 50/60/650/700 3 cylinder.....1.64 gear ratio. 650/75/80/850 4 cylinder.....2.3:1 gear ratio. 900/90/1150/115/1400/140/1500.....2.0:1 gear ratio. 1970-71 1150 & 1350.....1.78:1 gear ratio. sound about right?

[2us70]

Could be. Truth be told I never knew the actual ratios back then. I just knew what pitch and diameter props worked with them. I am surprised at how high the ratio was on the 49 in 3 cyl motors. I wonder how that compares to the OMC competition?

[WaterZebra]

Can any of the Mercury insiders explain the differences between the XS motors and the standard production motors? I raced the 500, the 650 and the 850 quite a lot but I stopped before the XS versions came out.

I just realized that the 650,850 and 1500 XS models were NEVER listed in the Hi Perf / Racing catalogs. Only the John Q Public sales brochures. Production run sizes to qualify as "stock" offerings? Warranty coverage? Hmmm

[FUJIMO]

...cause they were production motors...