PLEASE HELP

[Apollo Dynasty]

My first question is. What motors can I swap a 165 Mercruiser 4 cylinder (1987) out with? Where can I find an engine at a reasonable price?

 

[Bondo]

Ayuh,..... Welcome Aboard,..... There's no direct drop in motors,.....

So,.... How handy are ya,..??
A 4.3l is a good swap, as the drive's gear ratio will work, but ya need to build new motor mounts,.....
A 3.0l is abit easier, but ya need a outdrive geared to 1.98:1,....

 

[QBhoy]

Hi. The 3.0 4 cylinder will drop in on the same mounts pattern. Depending on the boat, you’ll get away with a prop change to suit her right. All 3 of the boats I know of that have had the 3.0 put in instead of the 3.7 didn’t need an outdrive gear ratio change. Just the prop. Wasn’t a huge difference in performance either to be honest.

 

[achris]

Hi. The 3.0 4 cylinder will drop in on the same mounts pattern. Depending on the boat, you’ll get away with a prop change to suit her right. All 3 of the boats I know of that have had the 3.0 put in instead of the 3.7 didn’t need an outdrive gear ratio change. Just the prop. Wasn’t a huge difference in performance either to be honest.

What??? Not a huge difference between a 170hp, 3.7L and a 140hp, 3L??? Are you kidding?

Ok, you're in the UK, where you totter up and down canals, maybe you don't notice the difference. But in the rest of the world, where we use our boats on oceans, most definitely you're going to see a HUGE performance drop from a 3.7L to a 3L... When I had my shop, I did a lot of 2.5L to 3L conversions (a similar ratio change as 3L to 3.7L) and the owners ALWAYS reported that the difference was 'night and day'... Also, a prop change may not be enough. Most boats run a 17" prop. Changing from 3.7L to 3L in the same boat would likely need a drop of 4", and finding a 13" prop is no easy task.

Just saying, dropping power is never a good idea (most boats start life with an engine that is barely 'adequate'). If you need to change out a 3.7L engine, a 4.3L is the best way to go, not to a 3L.

Chris......

 

[QBhoy]

What??? Not a huge difference between a 170hp, 3.7L and a 140hp, 3L??? Are you kidding?

Ok, you're in the UK, where you totter up and down canals, maybe you don't notice the difference. But in the rest of the world, where we use our boats on oceans, most definitely you're going to see a HUGE performance drop from a 3.7L to a 3L... When I had my shop, I did a lot of 2.5L to 3L conversions (a similar ratio change as 3L to 3.7L) and the owners ALWAYS reported that the difference was 'night and day'... Also, a prop change may not be enough. Most boats run a 17" prop. Changing from 3.7L to 3L in the same boat would likely need a drop of 4", and finding a 13" prop is no easy task.

Just saying, dropping power is never a good idea (most boats start life with an engine that is barely 'adequate'). If you need to change out a 3.7L engine, a 4.3L is the best way to go, not to a 3L.

Chris......

Never been in a canal in my life. Here on the west coast of Scotland. We have amongst the most serious waters in the world. So just a bit of a difference from your assumption .
but seriously, there wasn’t much difference at all. But the main thing was that the 3.0 was reliable. No 3.7 has ever been. If they haven’t blown up already...they are just about to...and you well know it.