Hi!

I wonder if sportmaster lower units steal speed when run less than 85 mph gps compared to a lower unit as XR. According to Merc Hi performance they only reccommend a sportmaster lower unit for outboards if running in excess of 85 mph. If not it steal speed. The main reason for sportmaster lowerunits is high x dimension (low water pickups) / eliminate blow out. How is it for inboard lower units?

Any ideas?

Cheeeers, Toffen G

The hydrodynamics are the same principal in both sterndrives & outboards. Ed

Hi!

I have seen several boats on this webb with sportmasters running around 82 mph. In principal they should swop lowerunit to gain speed.

Cheeers, Toffen

I bet once they are dialed in, they will get you a tad bit of MPH.

However, I watched a friend of mine pick up a brand new to him 30 Eliminator that had SM lowers installed, and were never tested before he bought the boat. First time out the boat would not get on plane at ALL.

Last spring I re-rigged a friends 22' Scarab with a new 496 HO/ ITS and a standard XR drive. Mercury did not recommend the Sportmaster and said it was designed for boats over 85.

I felt the regular XR was much too deep mounted on the ITS (stock x-dimention) the boat only ran 67 mph.

At the end of the season, I bolted up a new Sportmaster and instantly picked up 5 mph! No problems with planing at all.

Kurt

I was told that the Sportsmasters were slightly less hydrodynamic than than a normal lower unit because the design was intended to reduce/eliminate the high speed blowout that is more common with the normal design.