Mercruiser outdrives

[Rranger]

Are any mercruiser outdrives for 6 cylinder engines (depending on model I suppose) useable on a 8 cylinder engine or are they to light? Thank you. I have a alpha one on my 5.7 setup but know of a inline six setup with a good outdrive that might be had for cheap. I guess it's all about gear ratio to.

 

[Bt Doctur]

The inline 6 uses a 1.65-1 gear ratio. vs the 1.50 for the V8. You might be able to get a prop with enough pitch to compensate

 

[Rranger]

The inline 6 uses a 1.65-1 gear ratio. vs the 1.50 for the V8. You might be able to get a prop with enough pitch to compensate

This is why this board is so great. Thank you BT Doctur for your quick response, much appreciated.

 

[Scott Danforth]

the 4.3 v6 uses either the 1.81 or 1.62. the 5.0 V8 uses 1.62, the 5.7 V8 uses 1.47

 

[Scott06]

Yes you can prop around the drive ratio. I repowered my boat from a 4.3 to a 5.0 and kept the 6 cylinder drive because it had only 38 hrs on it. Had to go for a a 19" to 21" pitch prop to keep the rpms down. If I was less concerned about holeshot I would probably want a23" pitch, so if you go from a 1.47 to a 1.81 you may run out of available 23"+ props. What prop is on it now and where is WOT rpm?

 

[achris]

Also be aware that the yoke on the drive from an in-line 6 (the Mercruiser '165') is shorter than the yoke on a V8 drive. You'd need to pop one of the unis off and swap the yoke. Yokes on V6 drives are the same as the V8 drives. If the 5.7 is in a larger boat (say, 24+ feet) then it may benefit from the higher reduction. As far as the drive being 'too light', they all weigh the same. And have the same internals, apart from the gear set in the top box, for the ratio difference.

Chris.....