From what I can glean from das bible, the gear housing on the MagII is what they called E-Z shift, and different carbs. Oh, and like LD said, different decals.... LOL<br /><br />Chris.........
the mercury series xr4 and mariner mag11 series were made for bass boats, which resulted in a 142 ci powerhead compared to the normal 124 ci powerhead. in other words is has a 200 hp powerhead. the lower unit also has a smaller diameter which means less drag and the gear ratio is different. this explains why the same propeller on the xr4 will fit the 90-115 hp models. i am not to sure with the porting specs but the combination of the refinements means a great hole shot and excellent top speed. i have the xr4 on a ski boat and love having the best of both worlds, happy boating !!!
<br /><br /><br />Honestly I do not know. Just having some fun, but you will get your answer in the morning.