How to identify 3A from 3 drive
 

What tells me a drive is a 3a vs a 3 ? Are the differences noticeable ? is disassembly required ?
The drives in question are on a 1988 Cigarette flat deck with a hull s/n CRT3875K88.

Drive s/n's OB859086
OB859087

Thanks.
ed

Re: How to identify 3A from 3 drive
 

i have 3a's on my 79 mistress where did you find the number on the drive i'll look for mine and tell ya what it is.

Re: How to identify 3A from 3 drive
 

ttt. cumon somebody chime in im curious as well.

Re: How to identify 3A from 3 drive
 

3as should have a larger prop shaft (thicker diam shaft & splines)

Re: How to identify 3A from 3 drive
 

Ratman,
The serial numbers I found were on the side of the gimble housings.

RoseBudRacing,
Don't have a example of each drive to compare prop shaft diameters.

ed

Re: How to identify 3A from 3 drive
 

Found this in a forum search. Seems the best way to identify a 3 or 3A is prop shaft spline count and dia.

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.