Apha One Gen 2 gear ratio

[dlogvine]

I wanted to switch the outdrives on my old boat and a new one. Both boats have exactly the same Mercruiser 5.0 V8 engines, one made in 1998 the other in 1993. I checked out the gear ratio labels on both outdrives, the newer says 1.81R, the older says 1.65R. Both are Apha one gen 2 outdrives and the better one even has a label 5.0. Im not sure if the one on my new boat has a correct gear ratio, I've got it a couple month ago and it ran fine, had it on the water for about 10 hours this summer. So can I switch the drives, or should I keep the respective drives on the original places? And is there any way to check out what is the correct gear ratio for this engine, Mercruiser 5.0 V8.
Thx

 

[stonyloam]

https://www.seilermarine.com/info/me...atio-chart.php it kind of looks like the older one is correct ratio for a 5.0 but would be an Alpha I, the newer one looks to be a Gen II from a 4.3l. According to the chart. From thr dates you gave both should be Gen II's. See if you can find serial numbers.

 

[dlogvine]

thx stonyloam, now since neither one of the outdrives has a correct gear ratio, I need 1.61 and two outdrives that i have have gear ratios 1.81 and 1.65, which one should i use, looks like 1.65 has the same Tooth count and it is also made for v8 5.0L engine while 1.81 is designed for v6 4.3L engine

 

[stonyloam]

Well you may be kinda stuck there. If one is an Alpha I, and the other is an Alpha I Gen II, they are not interchangeable. See if you can come up with serial numbers (upper port side of the driveshaft housing). Do a search for " Mercruiser outdrive serial number"

 

[dlogvine]

No Title

I found the gear ratio for Alpha One Gen 2 outdrive is 1.62, for the engines from 1991 and newer, this is a modification of 1.65 (which is close to 1.61 from your table). So I changed the connector for the speedometer and tried to install this drive in my boat, but it is stuck about 1 inch and does not move any more. I dont want to destroy the splines on the shaft or on the coupler, so if you have any ideas as to what could be the reason for this, I'd really appreciate any advice. Thx.

 

[thumpar]

Look up under and to the middle and see if the shift shoe is lining up.

 

[dlogvine]

Spline alignment, shift gear lining were the first things I checked. I relubed the o-rings and even the u-joint. The problem appeared to be in a build up gunk in the bell housing. When I cleaned it up this morning the drive slid in without any difficulties. Thank you all