Diference Btwn a 3 and a 3a drive?
 

What is the difference btwn a 3 and a 3a drive? I think one thing is the prop shaft? What are all the differences?

Thanks
Jon

Re: Diference Btwn a 3 and a 3a drive?
 

Props= long hub and short hub.

Julie

Re: Diference Btwn a 3 and a 3a drive?
 

The III-A Super Speed Master (SSM) drive is a veteran of Mercury Racing drive stable. An updated version of the Mercury Racing III SSM drive, the III-A SSM drive features larger vertical bearings in the upper housing. The larger bearings provide increased rigidity for the driven gear, resulting in increased bearing capacity and longer life. Larger driveshaft splines provide greater strength, while larger pinion bearings hold lower bevel gears more rigidly, resulting in increased bearing life. A larger propeller shaft increases drive strength and is rear loading for improved shaft contact with the propeller. An extended “nose” on the gearcase improves water flow and boat handling.

Features & Benefits


Large driveshaft splines provide greater torsional strength.

Large vertical bearing in the upper housing provide increased rigidity for the driven gear and longer life.

Large pinion bearings hold lower level gears more rigidly resulting in increased bearing life.

Large propeller shaft is rear loading for improved shaft contact with the propeller.

Input ratings are 750 HP and up to 750 foot pounds of torque.

Extended nose on the gearcase improves water flow and boat handling.

Drive-line and plug-in models available.

Transmission required.

Counter rotation models available for multiple engine applications.

Gear ratios: (RH or LH) 1:1, 1.18:1, 1.33:1, 1.48:1 or 1.62:1.


When looking at the propshaft a III has 19 splines and a 3A has 26 splines. This is how to tell the difference quickly.

Re: Diference Btwn a 3 and a 3a drive?
 

Do the 3's use less hp then the 3a's? I assume that your HP and Torque ratings are for the 3a's?

Jon

Re: Diference Btwn a 3 and a 3a drive?
 

The HP and torque ratings are for the 3A's. I would think there would be negligible to no difference in the amount of horsepower difference that is used since they are both wet sump drives. Now if you want to slide into a VI dry sump you will lose less HP :D