1969 20' engine choice

[samuelcooper]

I am currently redoing a 69 SF 20 ft. (Will raise transom 5 in and deck 3 or so for tank and bailing). In looking ahead for engine choice I really like the e-tec. My choices would be 115 or 150. In reading old posts, the majority opinion seems to be 150 or more for hp. However, an e-tec dealer says the 115 will be plenty for the boat. So,...I'm wondering if anyone out there is actually running a 115 (e-tec or other) and can give info. on performance. I will rarely be on flat ocean so top speed is not that impt. But ability to plane and plow through rough ocean is. I took a 1977 Johnson off the boat and that was more power than I need.

[eggsuckindog]

Back when they were made we always hung inline 150 Mercs on 20's, I had a 115 on my 18 and it was just fine but could have handled the 150 and I wished I had done that for mid range in swells, the 115 would bog a tad. Keep in mind I think these new DI motors may be a good deal stronger than the old ones too, so a new 115 may be comparable, maybe someone else can add something regarding that.

You might check here for a motor-You will have to email in for a quote on a motor but they are on the biggest buy program this year so nobody can sell them cheaper, it involves dealer incentives for commiting to X amount of motors. You would have to weigh it against how good a relationship you have with a dealer, they can get their feelings hurt if he's a good friend.

www.usavemarine.com

[oldbluesplayer]

E-S-D - just a follow-up to your train of thought - I don't know when they changed the outboard motor hp ratings from measured at the powerhead, to at the prop, I'm thinking sometime after the 70's ?? but from what I think I know on that, wouldn't an older rating 150 be about equal to a new rating 130 - 135 ?

On the bogging, not uncommon on older, carbureted 2 strokes, mine bogs initially when coming off a prolonged low speed troll, till it clears out - don't have any injection motor experience, but I would suspect that more accurate fuel metering would help that greatly - two stroke carbs are notoriously hard to dial in for both mid range and top end, whether bike or ob, get too lean and you cook the motor, leave it fat for motor life sake, and live with the bog, unless you're racin, in which case you know your pushin the limits and in for constant tear down and rebuild anyways.

just some stray thoughts

Bill

[Michael Vezzosi]

More stray thoughts. Part I's '87 18 originally powered by a V-4 Johnson 112/115, slightly underpowered, in his opinion. Rebuilt V-6 Johnson 150, not sure of GPS WOT. Much happier.

My '79 20 MA originally powered by Merc. 200 BM blew up 1 hour after seatrial. Repowered 1999 V-6 carbed Johnson 175. ($600 for 200 HP carbs. (not necessary!)), not sure of GPS WOT. Much happier

The 20 is only minimally faster. Guestimatation: Both running very close to 50, light load, one occupant and trimmed. Both 15" transoms, and stock floor heights. Neither have T-top, trim tabs, or Porta- Potties. However, both do have fully stocked adult beverage coolers!

NOTE: We share a Jersey Speed Skiff, we guestimate closing in on 70 GPS, but thats unofficial as well. Stop down the LowCountry! Mike.

[Kahuna]

SC,
I have a 20' seafari myself with I/O, but two weeks ago I ran a clean 75 20' CC, with a very new 130 2-stroke yamaha. What a ROCKET!! full fuel, two people + dog, if you weren't holding on, you were going out the back. Based on the transome height, I would not put any more weight on the aft end of that boat even if the transom was 4-5" higher. I can't imagine 15 less hp would be a big production. The difference you will have between a 1977 outboard and a new one is going to be substantial. I do know somebody who is redoing a boat just like mine, raising the transom 5" adn plans on putting 115 2-stoke on it. 6 cylinders is too much weight, in my own opinion of course...

[NoBones]

200 hundred ponies on the back of NoBones is nice to have
when those famous afternoon storms sneak up on us in Florida. The weight is not that big of an issue with a raised transom and deck. Plus the fact that when you are
loaded up with gear and people the fuel consumption is far
less with more HP. You do not have to stuff the throttle
with a load. I have been in 20's with 90HP to 225HP
I'll take the 175-200HP range any day.
See ya, Ken

[oldbluesplayer]

Yes, I am running a 115, an old '84 Johnson V-4, although on a 20' Seafari - probably a little heavier and more windage than your CC. The motor is sound and solid, and with 2 on board and a full tank of gas I top out at 31 mph GPS - like you say, on open ocean I rarely can run it there, but it has a nice comfortable cruise point at 25-27 mph, put it in 2 - 3 ft chop and I'm down to 15 - 18 mph, holds a plane down to about 10 mph - which I have had to do when faced with unexpected 5 - 8' slop - would choose not to repeat that, thank you

If I had an open wallet, I would look at a 135, either an Etec or a Merc Opti - but then I have the 20" transom and original floor height, so motor weight would also be a concern to me. With the mods you're doing, 25" tranny, raising the floor, you won't have those concerns. Given that, a Suzy 140 fourstroke might be a real good choice, also.

On the flip side, there are those who think a 150 minimum is needed for these 20's - I just can't see that, given how mine runs with an old 115.

If I might ask, what hp was the old 77 Johnny you took off, that you thought was more than needed ? Some folks have put up to 225's on these boats - older, lighter two strokes, that would be a screamin machine... on a lake!!

All boils down to you, your preferences, need for speed, intended use, etc.

Bill

[Bigshrimpin]

If it were me . . . I'd look at a 115/140 suzuki or a 150/175 suzuki.

[samuelcooper]

Wow! thanks for all the comments. I am a little stuck on e-tecs now but can be persuaded. The 115 is a v-4 and weighs 375#. The 150 is a v-6 and weighs 427#. The Suzuki posted weights have confused me and cause me to doubt. The 115 seems to weigh 427 but they list the 140 at 410 or 420. How can that be? I wouldn't consider a 115 4-stroke (getting on plane a worry) but may go with the 115 etec. It is also about $3000 cheaper than the 150 e-tec. As to the old engine, it was a 175 Johnson. I'm gonna do some research on its weight. With the low transom, the waterline was only a couple inches below the splashwell docked. That old carb engine stalled bad but cruised great. It had no pee hole but did have temp guage and pushed H2O out of two exhaust ports just below the engine. My mechanic said those ports were supposed to be a couple inches out of the water or the carbs loaded up. With mine, they were under H2O when trolling but trimming up the motor when trolling so that they were out of the H20 helped with loading up and stalling. My conclusion is that the old Johnson was too heavy for the boat making it very stern heavy when trolling. I am aware that more power gets you on plane quicker and is usually more efficient when carrying a load or working against a sloppy ocean. But my thinking is that a boat that is less stern heavy will actually troll better and more efficiently - which I do often. Am I right or wrong? It seems that Seacrafts are designed to be stern heavy but what is the limit? In other words, what would Moseley or Potter say about moving weight forward (console, battery, livewell) to offset heavier engine? Wouldn't that change the ride considerably from the way it was designed? Thanks for the link to the motor source. Will check it out.

[JW-Tex]

To my knowledge the 140 Suzuki weighs less than the 115 because it is the same block as the 115 bored for larger pistons (less engine block weight).

I have the 140 and could not be happier....JW