gear ratio info

[bspeth]

R drive6683545. I looked on the stickys but my year (84) has quite a few different ratios,and the serial nunbers listed are all the same range for each ratio. Trying to figure my prop slip.Drive is backing a v6 229.Thanks

 

[alldodge]

Re: gear ratio info

You could pull the drive and count the ratio

 

[Fun Times]

Re: gear ratio info

6683545

Well from new your drive serial number is a Mercruiser MC1 with a 1.84:1 ratio. Model number 01847014.

 

[bspeth]

Re: gear ratio info

Fun Times,i am do not think it is an MC-1. Chris and bondo told me it was an R. Ratio still same though?

 

[Bondo]

Re: gear ratio info

Fun Times,i am do not think it is an MC-1. Chris and bondo told me it was an R. Ratio still same though?

Ayuh,.... The MC-1, R, MR, 'n Alpha 1 are the same in that respect,....

 

[Fun Times]

Re: gear ratio info

Fun Times,i am do not think it is an MC-1. Chris and bondo told me it was an R. Ratio still same though?

Bondo has you right, so when your looking up parts, stay with the (R) drive.

Here's your parts catalog just in case you need it someday.
http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=99964

Yes the ratio shown should be the same unless the ratio has been changed for some reason for things like altitude which is possible. Then the only way to know is to open the top cap of the drive shaft housing and count teeth on the drive gear and driven gear. Page 3A-8 has a chart reference if you need to go this route.

Start on page 3A-2
http://www.boatfix.com/merc/Servmanl/6/6A3R3.PDF

 

[bspeth]

Re: gear ratio info

Ok thanks.That means I have .285 prop slip. So Im sure some of that is trim but that's really high right?

 

[thumpar]

Re: gear ratio info

Yes that is high. I think around 15% is on the higher end of what you want.