Logo
FULL SITE MENU

what stern drive is this and...

T

tryintofixher

New member
Hi, new here. I just aquired a 1983 Imperial w/ 120 (2.5l) and a mercruiser outdrive. The serial on the outdrive is 226891. The engine is froze up and I am trying to identify what year engine I can put back in. My research shows the alpha 1 came out in 1983 but my drive does not say Alpha 1 and the serial # doesn't seem to be an alpha 1 ser. #

Want to hit the junkyards but I just keep seeing where only certain year engines will bolt right up?

Any info appreciated! tryintofixher
 
post a pic of the drive. It says mercruiser on it ? Not unusual to have a drive or motor from the year before maybe it's a pre-alpha.

You can drop a 3.0 in say up to 88' and just go boating no need to do anything else to the drive.

The 3.0 can be of any make, just change over the carb, mani, and riser, in one piece if it's other then merc.
 
Yep, says mercruiser..pics attached...thought I read in another thread that 3.0 required diff. flywheel or adapter or something?
 

Attachments

  • 000_0165.jpg
    000_0165.jpg
    77.3 KB · Views: 71
  • 000_0166.jpg
    000_0166.jpg
    92.5 KB · Views: 71
Update: I missed a # on the serial....6226891. It is an alpha 1.

so with this onfo, any 2.5 or 3.0 to about '88 is a direct swap with no additional parts?
 
The ONLY way to determine if it is a ALPHA 1 GEN 1 or a MR, the predissesor to APLHA 1 gen 1 is:

if you split the upper and lower cases, the vertical shaft on a MR has a o-ring groove and o-ring near the top, The alpha did not. (this assumes no one has replaced anything and it is all original). I just serviced my friends 1989 checkmate (should have a Alpha 1 gen 1), the lower was a MR, this tells me someone wasted the lower at some point in time in its life before he owned it and replaced the lower with what they could find and it was a MR.

The rest of all the parts are identical. The predissesor of the MR was the R, that had the o-ring and o-ring groove and a PRELOAD pin at the top of the verical shaft.
 
FYI... the engine cannot be any make!
Merc used GM's little inline 4 cylinder engines, and you'd best use another "like" GM 4 cylinder engine.
(perhaps Chief was suggesting that OMC's little inline 4 was also GM, and was the same base engine)
As mentioned, the 3.0L would be a good choice. ..... although I'm not sure about about the flywheel interchange.


Suggestions:

Separate the existing engine from the Flywheel Cover (aka Bell Housing in the auto world) and leave the flywheel cover attached to the inner transom plate. This way you will not become confused with the rear mounting hardware.

Check the drive coupler internal splines making certain that there is no damage to them.

Read the OEM procedure for engine drive coupler alignment.
You'll need the alignment tool.
This is important if you wish to prevent coupler failure.

Look carefully at flywheel ring gear teeth while you have access.

Learn the subtle differences between the auto and marine engines before you proceed (if you plan to use an automotive built engine).

Have fun! :)
 
Last edited:
Thanks guys! You're info should get me started on the right track...Ricardo, u hit the nail on the head...I'm used to automotive ;)

Found this surfing the web if it helps anybody...no need to crack a case for I.D. :

GENERAL
Beginning in 1983 Mercruiser introduced the R/MR/Alpha 1 series of sterndrive models. These units differed greatly from previous years not only in design but also in that the flywheel housing on the engine changed at this point. This creates one of the big break points customers should be familiar with when inquiring about re-powering older boats. Since the flywheel housing changed from 1982 to 1983, you cannot couple a new engine to a pre-1983 sterndrive unit as the rear engine mount spacing differs on the new engine and therefore will not match to the old style inner transom plate. The other difficulty is that the newer 14 inch flywheel utilize a larger coupler that prevents re-using the old flywheel housing on the new engine. The R/MR/Alpha Generation 1 models began in 1983 and ran production through 1990. The serial numbers for these models ranged from 6225577 Thru 0D469858
The Alpha Generation 2 models were introduced in 1991 and are currently still in production. The Gen 2 units have been broken into several different serial number ranges as follows:
1991 thru 1995 - 0D469859 Thru 0F679999
1996 thru 1997 - 0F680000 Thru 0K999999
1998 and Up - 0L100040 And Up

source: http://www.perfprotech.com/store/articles/alpha1-alpha2-sterndrives.aspx
 
Back
Top