Merc 2.5L on Seafari?

[Bigshrimpin]

2.5L 280
http://www.youtube.com/watch?v=RT1N6...eature=related
2.5L 260
http://www.youtube.com/watch?v=wy8mz...eature=related
2.5L drag => 348 on a Dyno
http://www.youtube.com/watch?v=mM9l774zLo4

[Blue197320]

big, is 5800 rpm too much for a 2.4L? the prop im looking at has been used on here with a 20sf and 200 merc and gave 5800 rpm and 58mph. its a 13.75x21 stainless. they make the same size in aluminum that i was going to get.

[Bigshrimpin]

5800rpm is what I prop mine for . . . 5800 is the max recommend RPM in the factory manuals for the 2.4L motors. Without the spark advance/idle stabilizer module and the oil injection they're good way above 5800rpm.

[Fr. Frank]

Blue, my target RPM for my 2.4L on the back of my '72 Seafari was 6000. I actually turned 6050 at WOT, trimmed out, 1 person and 30 gallons of fuel with my reman'd 2.4L XR4. Originally 150hp, it dyno'd right at 190hp after the rebuild. I was turning a custom made 15.25"X16.5"P PowerTech OFS 3 blade. (still have the prop, the motor was sold)

Fully loaded, with 7 persons, 30 gallons of fuel, fishing gear and a full live-well, I could still turn 5700-5750 rpms. I wanted to be able to turn the maximum of the reccomended maximum rpm range with the boat a maximum load. I call that running "max of max at max" That way I'm never over-propped so that I cannot take advantage of the full power of my motor in an emergency.

BTW, Tim, on a cold day, after I had about 20 hours or so on the motor and my new prop, I once ran downwind in a light chop, 2 guys on board, and about 10-15 gallons of fuel, and ran and maintained 46 knots on the GPS, or about 53 mph for more than 10 minutes with that XR4 on the back of my Seafari. Had a nosecone and LW pickup, too. Threw one heck of a rooster tail for a Seafari, had to be 8-10 ft high. And yes, that's right on the edge of chine-walking for my boat. Actually fell into a chine walk a couple of times before re-stabilizing.

The reason? Trying to get in off the Gulf of Mexico from 20 miles out before the really nasty squall hit. We made it, too.

[Bigshrimpin]

http://www.youtube.com/watch?v=5b90Fq7Cmvk

http://www.youtube.com/watch?v=5UG61hdwxjg&NR=1

[McGillicuddy]

Wow, Bigshrimpin, that's thrill seeking! Maybe I'll stick with a little less power and more hull in the water, even 50mph is a little spooky What kind of economy are you getting w/ the 2.4L? 2.5L?

I came across a '94 2.5L for $1500. Seller claims excellent compression and overall near perfect. Certainly looks clean. Price seems really good, no?

-McGill

[Bigshrimpin]

1979 2.4L 200 vertical reed with the WH-11 carbs (small venturi) . . . I get better than 3.5mpg at cruise up to 35mph. After that economy falls off real fast. 2.4L motors with the small venturi carbs like the mid 80's 2.4L 175's and the early 2.4L 200's get great economy. The larger venturi carbs on 2.4L 200's and old 225 (wh-22's, wh-28's, wh-31's, wh - 15's, wh-20's) will feed the motor more fuel, but still will be better than 3mpg at 4000rpm pushing a 20. 2.5L motors are a different story . . . even 2.5L 150 EFI will burn more than a 200hp 2.4L Carb motor.

I think 2.5 - 2.75mpg would be ball park for a 2.5L on a 20, NoBones has one on his 20 . . . he could probably give you exact numbers. fgbiv had a 2.5L Mariner Magnum III on his seafari.



[img]http://groups.msn.com/_Secure/0RwA6DjoVavRAkn34DpSL6O4DZoaANV9jPwT!iUcLkvOSS8vYV *KDTRLRlMrHSptCLtxq64wr7wF98ztF!H8rwS2JL!X6yhbofYk iz*powz8/74_Safari.JPG[/img]



Honestly I think a 2.0L 150 is a fantastic match of economy and power on the 20's. The 2.0L's will get you to 40mph and cruise at a nice west coast 25mph . . . I had one on the MA when I sold it. 25mph was 4mpg cruise.

[McGillicuddy]

Thanks Bigshrimpin,
You've opened up the proverbial box so here are a few more questions.

Can I assume an '88 175hp would be a chrome bored 2.4L and be of reasonable weight? And is the chromed bore an advantage or disadvantage.

Also what is the 2.0L designation, is that the standard black max 150 or the inline 6 variety, or something else and how do I tell them apart? And what's the weight of the 2.0L.?

What should I expect/be willing to pay for these older motors?

-McGill

[clb33fyxj]

http://www.youtube.com/watch?v=RLbV1hoeQ1s

twin 2.5 race O/B's. gotta love the sound of 7500rpm. the boat in the vid will do over 100