SF20 repower

[poco]

Hello

I have a 71 SF20 (open transom) that currently has a black max 150 on it. My situations changing and the boat will be living on a lake and run around only a few days every few month so i'm looking to re power and go fuel injected. If it was just me id keep the running black max for now but my some family will be running it from time to time so the simpler the better. I did search and read all the threads that related but most of them where ocean related conditions.

I've read a ton of great info on E-tecs and I know max 400lbs on the transom so I didn't know if a 90HP would be enough to motor 4 adults minimal gear day cruising at 40mph ball part.

Any suggetions would be great, thank!

[JohnC]

I did a quick search here for things I remember reading in the past. There is a lot of info from a few folks that have that power if you search for it. Both posts linked below are guys that do long runs with this motor - Terry does it loaded with lots of heavy dive gear. I have not been on a boat with this power - only read about it as its on my wish list. I have never heard anyone say it is not enough power. Good fuel burn, mid-30's top end and can stay on plane down to 13 mph or so (which is awesome when the water gets choppy).
I think the only drawback would be resale, simply because some of your potential buyers would have some prejudice towards smaller power (I'll pass on the manhood comparisons!). Since newer 20' boats have big power it just seems normal to think that 150-200 HP is normal fare for this hull. This is not a newer hull. Mr Moesly put some real genius into making a remarkable hull and I think that the 90 fits his design - with regards to weight and power - closer than any new motor out there.

http://www.classicseacraft.com/commu...t=29102&page=2

Post # 16 & 19

http://www.classicseacraft.com/commu...erry%2Aengland

Post #2

Read lots of stuff and good luck with your decision.

[Capt Terry]

I replaced the Black Max on my ‘76 Seafari with a ETEC 150 HO. It hit 50 mph initially but when propped to be in the recommended WOT rpm range it runs about 42-43 mph with the bimini up. Your boat is lighter than mine, more like Dirtwheels’ Squidlips which think has an ETEC 135. The ETEC starts immediately after a 6 month shutdown, is quiet and thrifty on fuel. See what responses you get, but doubt a 90 will meet your requirements.

[poco]

Originally Posted by JohnC

I did a quick search here for things I remember reading in the past. There is a lot of info from a few folks that have that power if you search for it. Both posts linked below are guys that do long runs with this motor - Terry does it loaded with lots of heavy dive gear. I have not been on a boat with this power - only read about it as its on my wish list. I have never heard anyone say it is not enough power. Good fuel burn, mid-30's top end and can stay on plane down to 13 mph or so (which is awesome when the water gets choppy).

Man idk how I missed that one thread that guy has a very similar situation thank you! Sounds like 35mph WOT max with a 90hp but damn good on fuel and weight. Im not to worried about resale at the min but that is good to keep in mind.

[poco]

Originally Posted by Capt Terry

I replaced the Black Max on my ‘76 Seafari with a ETEC 150 HO. It hit 50 mph initially but when propped to be in the recommended WOT rpm range it runs about 42-43 mph with the bimini up. Your boat is lighter than mine, more like Dirtwheels’ Squidlips which think has an ETEC 135. The ETEC starts immediately after a 6 month shutdown, is quiet and thrifty on fuel. See what responses you get, but doubt a 90 will meet your requirements.

hey yeah sounds like ETEC is the fan favorite and its ganna see less use over the next year so that kinda reliability is awesome! The 90hp sounds good but could be just a bit slow theres a few people looking to possibly ski behind it deff not the primary reason for re powering. Its really just the weight as it looks like a 115 and 90 are similar prices used but cruising at 40mph on the river can really make a day more enjoyable getting from place to place.
Thanks

P.S. I love that Black Max though she has yet to let me down just a fuss somtimes to get going and she loves gas, soo much gas!

[JBASS02]

I've got the 90 that JohnC referenced. The engine has ~150 hrs and ~2,200 miles. I'm happy with the motor. It is still running an aluminum 15 pitch prop and top speed with normal load is 32-33 mph(stainless would probably increase mph & mpg). It jumps up on plane quick and averages around 4.5 mpg for the day. I will say this, I grew up on bass boats fishing tournaments and if I was fishing larger lakes exclusively I'd want a faster boat. The ocean out of Santa Barbara is rarely flat enough to run much faster than I do.

[poco]

Originally Posted by JBASS02

I've got the 90 that JohnC referenced. The engine has ~150 hrs and ~2,200 miles. I'm happy with the motor. It is still running an aluminum 15 pitch prop and top speed with normal load is 32-33 mph(stainless would probably increase mph & mpg). It jumps up on plane quick and averages around 4.5 mpg for the day. I will say this, I grew up on bass boats fishing tournaments and if I was fishing larger lakes exclusively I'd want a faster boat. The ocean out of Santa Barbara is rarely flat enough to run much faster than I do.

So this would be taking over the job that a pontoon boat was doing at the moment, I was looking to sell my SF20 and then some family was looking to replace a pontoon boat at my grandparents place. Kinda felt like a win cause I really don't want to sell it and they have a place to put it and are willing to buy in on it.

BUT its a big damn river and yeah 35mph WOT may be just a tad slow but then again its not like that pontoon went any where quickly.

[mnwnvc]

I think for the cost difference I would go for a 115 hp instead of the 90. I have a 115 Opti on my 20 and am very happy.

[poco]

Originally Posted by mnwnvc

I think for the cost difference I would go for a 115 hp instead of the 90. I have a 115 Opti on my 20 and am very happy.

yeah it looks like used they are very close in price, I guess im on the look out for a used 115 now, thanks !