1988 3.0 Mercruiser 140 hp questions

[Bushwacker]

.. so you think something like a 4.3 would be better..I am on a budget as usual!!! I do not want to have to change out my outdrive or mess with motor mounts etc!!!!

Fred, I recognize that a near-stock original setup is probably the cheapest, but as a mechanical engineer I'm just partial to smooth running machinery! A large displacement I-4 w/o balance shafts will buzz quite a bit but you might not care about that, provided it's reliable. Just thought that while you're looking around, it might pay to think out of the box in case you find a deal on a more modern set-up. It's probably not that hard to find a bayliner full of rotted plywood with a fairly low time engine/outdrive, so finding a donor boat could be a viable option if you have the time and like turning wrenches! I think Skip has found that replacement parts for some of the really old outdrives can be pretty expensive. A V-8 would be way too much weight unless you wanted to spend a lot of $ for aluminum heads and fresh water cooling! The 4.3L V-6 isn't naturally balanced either, but it's a little smoother than the big I-4, similar weight and more power. There was a Seafari on here some time ago with that setup and it looked like a neat installation.

There's a reason they did 3 valve jobs on that old engine as described in that original ad you sent me: it was underpowered with that 120 hp engine! Sounded like they did a lot of diving, and if they loaded that boat up with 4 divers, tanks and gear, and ran it w/o a vacuum gage, they probably ran it well under 5" vacuum, which will burn valves pretty quick. That boat is not underpowered with a 140 if you don't overload it . . . 2 different 140 I/O Seafari's have made the 170 mile trip to Green Turtle in the Abaco's with me, and they would run about 23-25 mph at 7" vacuum. They weren't heavily loaded however, and because they're 5 mpg rigs, they didn't have to carry nearly as much gas as I did with my old 115 V-4. They burned about 45 gallons to my 65 gallons!
Denny