mercruiser outdrive ratio

[big ken]

i have a inline six with a 165:1 ratio what would be the pro or con of putting in a 150:1 ? thanks ken

 

[ziggy]

Re: mercruiser outdrive ratio

what are ya trying to accomplish bk?

all info that i've ever seen on the L6 engine has a 165:1 ratio. so i fig. it's the proper thing to have...... i can see no pro, and only cons...... your goal is to reach between 3900-4300rpm@wot leaning to the high side... the proper ratio works well for achieving this...

 

[TilliamWe]

Re: mercruiser outdrive ratio

No pro unless the drive is broken.

The big con is that with the taller gear ratio (1.5 is a taller gear than 1.65) you will have to get a replacement prop in a smaller pitch than you currently have. And if you are already running a 17 pitch prop, you may have trouble finding a 15pitch or smaller.

 

[turborich]

Re: mercruiser outdrive ratio

I did this same exact swap to my boat. my 165 drive was bad & I had a good 888 drive with the 1.50 gear ratio. I left the 17 pitch prop from the 888 drive on. Everything was just fine & RPM's were pretty much right where they needed to be. It worked out very well for me.

 

[TilliamWe]

Re: mercruiser outdrive ratio

Good for you rich, you got lucky!

 

[ziggy]

Re: mercruiser outdrive ratio

i'm curious....

RPM's were pretty much right where they needed to be

what exactly did you end up with for wot rpm?
for instance. with a normally loaded boat, i get 4300 @ wot. and i've seen 4400 with a higher than i normally run it trim (trying to squeeze that last mph out of it ya know, ).....

 

[180shabah]

Re: mercruiser outdrive ratio

Ken, what are you hoping to accomplish?

 

[big ken]

Re: mercruiser outdrive ratio

Ken, what are you hoping to accomplish?

just seen a deal on a 150:1 and was wondering if it was worth switching. but i probably wont. any feedback on those SE upper and lower units? thanks ken

 

[180shabah]

Re: mercruiser outdrive ratio

There would be absolutely no benefit to changing gear ratios. As for the quality of SEI drives. I have no complaints with mine(SE116 - lower) and those that I have heard complain - it is usually not any more serious than the paint doesn't hold up as long.