Can I install a newer outdrive?

[MaxGlide]

I have a Mercruiser MR-1 drive, serial number 3843732. I’m pretty sure my upper gear case just went. If needed, could I put a newer generation outdrive on it? Say if i found an Alpha 1 that has been rebuilt (as opposed to fixing the old one?) Picture is of my current drive.

 

[matt167]

SEI will sell you a new outdrive and parts needed to install it as cheaply as you will get. Think you can basically go up to alpha one gen one which is about 1990

 

[Scott06]

Any mc1, R,MR, or alpha gen one will bolt in and work fine if gear ratio is same

 

[MaxGlide]

Any mc1, R,MR, or alpha gen one will bolt in and work fine if gear ratio is same

Thanks! How do I find the gear ratio on mine?

 

[Scott06]

Thanks! How do I find the gear ratio on mine?

On port side or what engine do u have …

 

[nola mike]

I couldn't find that serial number...what's the engine behind it? Otherwise you can either remove the top cover and count teeth (if there are any left) or count the number of input shaft rotations/prop rotations (again, not with a broken drive)

 

[Eric 3.7LX Alpha 1]

Here are a couple of other ways to know your gear ratio. The universal joint splined yoke will have a letter stamped on the side of it, which indicates the ratio, see chart below.

 

[MaxGlide]

On port side or what engine do u have …

I have a Mercruiser 140

 

[MaxGlide]

Here are a couple of other ways to know your gear ratio. The universal joint splined yoke will have a letter stamped on the side of it, which indicates the ratio, see chart below.


View attachment 368964

Thanks for the info, this helps a lot!

 

[MaxGlide]

Here’s a pic of my drive.

 

[nola mike]

Here’s a pic of my drive.

1.98/1.94 ratio

 

[ROY WILLIAMS]

Here’s a pic of my drive.

yes my alpha 1 MR is the same picture... ratio 1.84 20ft 3,000lbs ..170HP..470

 

[nola mike]

yes my alpha 1 MR is the same picture... ratio 1.84 20ft 3,000lbs ..170HP..470

He doesn't have a 470

 

[Scott06]

Here’s a pic of my drive.

You should look at a SEI 106 aftermarket replacement for a alpha gen one , you need the 1.94 ratio https://www.sterndrive.cc/product/Fits-Mercruiser-Gen-I-1-94-Ratio-1941017.html

 

[MaxGlide]

Here’s the manual with the serial number range I’ve been using for parts. Shows gear ratio of 7.98. I assumed it was a typo of 1.98

 

[Alumarine]

As Nola Mike and Scott06 said either 1.94 or 1.98 is what you want.

 

[Scott06]

Here’s the manual with the serial number range I’ve been using for parts. Shows gear ratio of 7.98. I assumed it was a typo of 1.98

Yep was 1.98 on older drives, at some point they changed the tooth count/gear design so all ratios changed slightly 1.98=>1.94, V6 went from 1.84=>1.81 … etc

 

[MaxGlide]

I THINK I MAY HAVE FOUND THE PROBLEM… the gear end yolk sheared off at the blue mark. How could enough torque be created to shear it there?!

 

[nola mike]

I THINK I MAY HAVE FOUND THE PROBLEM… the gear end yolk sheared off at the blue mark. How could enough torque be created to shear it there?!

Suspect that isn't your only problem, guessing something else locked in the drive. What happens when you try to spin the prop?

 

[MaxGlide]

System went as we were cruising along at 3000 rpm, barely a little “cruump”. Now it doesn’t spin in forward gear at all and moves a bit in reverse, with a click.