1969 20' engine choice

[eggsuckindog]

Frank can he do the rectifier himself? I've never had to do one or adjust the tach, thats why I said to call Mike about the rec and the tach, it just can't be too hard once somebody tells you where it is and it should be just change wires????

Finestkind: thats why you buy the SS, they can be fixed almost everytime, I know you guys have some rocks up there that could render one unfixable but the alum's are shot everytime.

Boy we really derailed Sonny's thread here

[Fr. Frank]

The back of the tach should have a small rotary switch witch can be moved with a small standard/flat screwdriver to the appropriately marked number of alternator poles. My Merc, with a teleflex tach uses the 6 pole setting. Of course, you can also try the different settings and see which one seems right. It probably won't hurt the tach, it just won't read right.

[Bushwacker]

You are wise to pay attention to weight! As much work as you're doing to that boat, have you considered adding a good bracket like the Potter/Seamark deal to offset the weight of a heavy motor?

I ran a 1975 115 Evinrude (~90 HP at prop) on a 20' SeaFari for over 30 years, much of it offshore, including 6 trips from S. Fla. to Green Turtle Cay in the Abacos (Bahamas), a distance of ~160 nm one way. Power was adequate because it's only a 300 lb motor, so boat was well balanced and rode great. Cruised @ 4500 rpm/22-23 mph with very heavy load in 2-3' head seas or the 2' square waves (2' high, 2'apart) common to Little Bahama Bank; could plane at 12-13 mph/3000 rpm using trim tabs and full downtrim on motor and ride comfortably (sitting down!) in 4-5' head seas! Had zero durability problems; only complaint was fuel mileage (2.0-2.8 mpg). Last March I added a Seamark fg bracket and repowered with a 150 E-Tec; it's an awesome motor but way more power than this boat needs! Will run 50 mph but will start to chine-walk at that point; best cruise is 2700-2800/25-27mph/5.2-5.4 mpg! (Based on I-command tach & GPS spedo) I considered the 115 and would have probably bought it instead but they didn't start production till June 06. Evinrude is really sandbagging on the E-Tec hp ratings(NABM requires ratings to be within 10% of measurements); their 06 brochure contains hp/torque vs rpm plots for the "225" V-6 that shows peak hp at 240, so I suspect the "150" is at least 160-165, and the "115" is probably a 125, or 35 more prop hp than I was satisfied with for 30+ years!

I also considered a 140 Johnzuki (similar wt to 150 E-Tec)but it's fairly small displacement and I felt it might be a little weak on mid-range torque, which is important for running in heavy seas. The newer 4-strokes have more cubes but are also much heavier, so I wouldn't consider them w/o flotation bracket.
I'm a mechanical engineer and spent several months reviewing
engine options, so call me some evening at 561-622-7670 and we can talk and trade e-mails.

[WillyC]

Thanks for the info DKB. Thats good stuff. I'm in the middle of a restoration project on a 20' sf. If I had the cash I would probably spring for the 175 suzuki but I think it may be a tad heavy for my 25" notched transom. When the time comes to make a purchase I might get a 130 yamaha 2S (If I can find a good used one). Seems to be a good match.