1980 20 sf power?
 

I have a1980 sf i am repowering i have a 225 efi now i am looking to put on a four stroke is a yamaha 200 to heavy? And would a150 be enough motor?

20' or 23'?

it says 20 and yes it is to heavy - a 150 will work great a 225 is way more than needed

Oops, missed that in the title.

Way heavy, a lot of 23 run with 225s. Not necessary on 20 as efficient as a Seacraft.

I had a 135 opti-max on my 20' but there were times I wished it had the 150.

OK Scott, a 23 could barely handled it anyway

I saw an 87 20ft with a four stroke 150 on the transom and it had water coming in the drains with no one in the boat

Hey guys thanks for the info. Like i said i have a 225 2 stroke now. I love the speed but the boat is being restored right now and i am looking for good fuel economy but still speed. Again thanks

I'm at 415, and my scuppers will come in if I walk to the back with nominal fuel, runs back out when at the console no problem, thats why I say about 400 is it. Sitting empty is no issue at all, just add another 200 and maybe the baitwell and its coming, not a big issue in Fla summers.

Then look at an Optimax or E-Tec that will have similar fuel consumption to a 4 stroke (> 4 mpg) but are much stronger on mid-range torque and power/wt. The Zuke 140 at 421 lbs (before you put 11 pounds of oil in it) is relatively light for a 4-stroke and the only one I'd even consider and would probably get you about 40 mph. However the small block 2.7L V-6 E-Tec at 433 lbs is a much stronger motor. The 150 is actually 165 at the prop with tons of mid-range torque and should give you mid to upper 40's. The 175 & 200 may have a little less mid-range torque, but should have enough top end power to put you over 50 mph.

Yam hpdi 200 weighs around what a 140 4 stroke zuke is, way more power and fuel burn is good, just burns more oil...

I have a old 91 150hp evinrude and it fine till my fat azz steps to the back

I don't mind the water coming in as long as it does not come over the transom. Its Florida i don't mind wet feet lol

I have a 225 efi merc weighing in at 475 and when I'm in the back of the boat a little water fills the drains but none on the deck. And like you cjm1300 I too love the speed!

your NEW option is the new Yamaha 200 4 stroke... it is built on the 4 cylinder so it weighs roughly the same as the 150 4 stroke.. BUT you will have to PAY for the NEW motor... I'm sure they arent giving them away..

My stats:
Lots of bottom paint
366lb 4 stroke 100HP
Plus
60 lb kicker
Plus a under prop fin and 4 blade prop for more lift but more drag
34 MPH
5-6MPG (I run a 20 gallon tank- no need for more)
12 knot/14MPH planing speed

With no fin and a different prop(12.75 x 17) and no kicker I think 37MPH could be had, maybe 38 with a SS prop and no bottom paint, albeit with a higher minimum planing speed.

I don't need trim tabs.
Just a data point. I spent a lot of time and a little money on props and fins to get the best out of a light low power outboard. I don't even have a stainless prop, so if 40 MPH is your goal, there might be a light weight efficient way to get there with something like an Etec 115 or 130?

I have a 1973 20sf all redone w/150 etch very happy performance 43 mph with 2 good size people aboard

My 20' did that with a 2-stroke 135 on it. They are SeaCrafts, they ride too low in the water for where the original deck is (which is why some of us that have had them redone raise the deck - to FINALLY have dry ankles). Sadly, Tracker/BPS didn't remedy this when they built them either, the Lefty Kreh "Master Angler" will suck water in the scuppers when sitting at the dock if you step in it. Great design, huh?!

the 150 Etec is one of the strongest ponies out there, seems they maxed the allowed 10% allowence on HP - even compared to their other motors


having water come in with no one in the boat with a 135 2 stroke the boat had other issues, nobody with V6's have that issue, mine won't, full of fuel and the baitwell full and a T top

My 18 with a Yamaha 200 2 stroke will only have water come in if I stand in the back corner. I weight 325 though.