Repowering 20' Sportsman

[SteveM]

I have Tommy's brothers old 20' Sportsman here in The Bahamas.

It currently has the 4.3L V6 with an Alpha drive. It's aging and I believe the sterndrive may be leaking and in need of some repair.
It's heavier than the original 165 inline 6 and tight in the engine box. We have lead ballast in the bow to offset the extra weight in the stern.

I looked into the Yanmar 4LH paired with a Bravo 3X sterndrive.
Cons: Expensive. Somewhat heavy. Bad reviews online regarding sterndrives melting when paired with diesels.
Pros: 4LH is mechanical and I'm able to buy it here in The Bahamas. Local boatyard is a Yanmar dealer and service center. It'll fit in the box.

After a lot of analysis, Yanmar, New Mercruiser, etc. I'm actually pondering the idea of getting a rebuilt Inline 6.

Pros: Fits in the box with easy access for repair. Cost is minimal to purchase. Proper weight for the boat.
Cons: Not as fast as other options....BUT, I don't need to go fast, I just need to get on a plane. Parts may be tougher to get, but at these prices I could purchase two or three rebuilt engines...hell I could buy one every year for 20 years.

I don't know if it works with a Bravo 3 which I would like simply because the dual props.

I'm on Man O War Cay, Abaco Bahamas. We have Edwin's boatyard and the Albury Brothers. I can get the boat dolled up, gutted and painted in the yard. I'm sure they'd help with the install but after that I may be on my own with maintenance and repair. I've been repairing the existing V6 currently.

Would appreciate any intelligent input.

[Ironworker]

I've got a friend that repowered his 20' Bertram with a 175 Suzuki Outboard fitted on a bracket. Its a very fine boat but it needs trim tabs for stability due to the deep vee.

[SteveM]

Rick, that's what my son wants me to do...But I'm more of a traditionalist. My thought is if I'm going to do that to the boat, I could just get a 20' Albury instead of messing with the esthetic.

I think trim tabs either way are likely a good thing on this little boat.

[Ironworker]

Steve,

I can appreciate your traditionalist instincts. But I can also see your son's perspective as well. The 20' Bertram Hull is a great one as is the 25. These boats shine with outboards. Also slightly raising the deck so they will self bail is another "improvement" depending on ones perspective.

I really like the Albury's but those hulls are nowhere close to the old Bertram hulls. The Bertram hulls ride better, are drier and are more efficient.

BTW, I'm not too far from you guys in the Bahamas. I'm down in Spanish Wells.

[Tony Meola]

Steve

I would think if you go outboard, you need to find one with a long shaft to get you into clean water below the deep V. Brackets may solve that problem also since the engine sits further back, a little deeper and should be in clean water.

Not sure about diesel stern drives. I believe Mercury tried it with a rebadged cummins and I believe they gave up. Not sure why. Probably cost.

Sorry I can't help you any further on that one but the outboard should work.

Why don't you send Rocket a PM, not sure what he did but he is pretty happy with his 20.

[Bruce]

Yanmar way back when they started to power the power boat industry instead of concentrating on sail boat power, I had the unfortunate distinction of being involved in a project of repowering a power cat with 6LY diesels and bravo drives. Drives lasted less than 100 hrs each. The torque destroyed the innerds.
Round 2 had me replace the bravos with speed master drives and using tranmissions to do the shifting which worked but cost was nuts. (owner was head of multinational Corp and had money to burn)
Since then bravo drives that are used with diesels get hardened gear and shaft sets, at least they were way back when. Mastry at one boat show powered a Donzi with a 6lp with bravo drive that did 70 mph.

I did a few 4lh stern drives, and they worked. But it's not cost effective by any means.

The 165 with alpha drive is cheap and traditional. Only down side is most all were raw water cooled.

I'm with Steve on tradition, but his son makes a good point with OB. Having met his son many years ago, he was one smart kid. I'm sure he only got much smarter since then.

[SteveM]

Thanks Bruce!

My son can put an outboard on it later on, when I'm too old.

I'm going to try the 165 inline 6 and an Alpha drive, I believe I saw a freshwater cooling add-on, on YouTube.

It's a very low cost option and if I don't like it later on I can change it then.
I'm just starting retirement and I'm enjoying getting my hands greasy.

[DanielM]

Steve,

Glad it made it through the hurricane. I thought I had read that your 31 made it through, but I didn’t remember reading if the B20 did. I’m glad it made it.

Given that it’s an original sportsman I wouldn’t modify it with an outboard. It would be a shame to take a sawzall to a Sportsman.

The 165 should be a relatively easy motor to keep running, no idea on part availability though. Seems like they made enough of them that parts wouldn’t be too tough to find, but I don’t know.

Funny thing, I was just looking at old pictures of your boat today. I was flying back to Texas today and had time to kill on the plane so I was looking back through old photos on my phone to delete some old stuff and ran across pictures of Eddy on that boat at the NC rendezvous from a few years ago. It’s a good looking boat.

Good luck. I’d definitely keep it I/O if it were mine.

[SteveM]

Daniel,
Thank you for the support.
My 31 was in FL at the time of the storm so it's fine. The little Sportsman was the only boat in the Man O War yard that didn't tumble off her blocks. I emptied all the fuel out (actually pulled the tank to get every drop), pulled the carburetor and cleaned it, changed some old fuel lines and it only started with fresh fuel poured into the carburetor. Called my son, he told me from the beginning I should have checked the electric fuel pump. That was it. Nothing was coming out. No resources here. So I pulled it off, sprayed carb cleaner in it and tapped the openings against a 2x4. I got some goo out of there and water and it then flowed fuel after. She's running consistently now, but under load at high rpm's she hesitates a lot. Like she's getting intermittent fuel or spark. I think I'll change the plugs this week, maybe they are nasty. The other thing is the linkage cables must be old and stretched. I can get it to work in both forward and reverse, then the next day in reverse it dies again. And I've got a leak I think probably coming from the sterndrive, I slowly get water in the bilge. So I run it quickly, and put it back on the lift. After the plugs I'm telling myself that I should spend my time on stuff around the house instead. I need to build a new deck to the laundry room; and I have 3 rain cisterns, only one is hooked up to the plumbing. I need to buy some pumps and PVC and get the other two hooked in, my wife is returning soon and I don't want to run out of water while she is here!

I too would not like to see a sawsall hit the boat...I know some will say put bracket.
I'm just one of those people that have always shuddered at the idea of putting "Whale Tails" on old Porsche's or a Floyd Rose Whammy Bar on a vintage Stratocaster.

Bruce,
I found a few places that offer closed "Freshwater" cooling systems for these engines.
I'll ask Michigan Motorz if they can supply one or at least add it on after they refurb everything.

[ktm_2000]

I had a Hiliner 222 gypsy which was designed by Ray Hunt and I would consider it revision #2 of the Bertram 20. I converted it to an outboard and powered it with a 175 yamaha the boat flew, cruised easily at 24kts at 3400rpm and would top out in the upper 30kts. I notched the transom when I did it and there were no poor handling characteristics from the conversion. The performance of the 175 Yamaha matched the output of the 302 V8 it replaced so there is definitely some efficiency gains there.

I think if I were to do it again, I would have done one of the Bob's jackplates like Cam did on his B25 and would not put a notch.

Any outboard conversion also has to contend with a fair amount of structural work as well as trying to actually acquire an outboard which is no easy task right now, so the thought process to remain I/O might not be a bad idea right at the moment.

[Ironworker]

Steve,

When you change the plugs change the plug wires. I'm not a gas inboard guy but I spend an inordinate amount of time working on airplane engines. Plug wires go bad all the time

[Rawleigh]

Lenco can set you up with fresh water cooling. Great guys to work with.

[DanielM]

Sorry I can’t offer much advice as it’s been quite awhile since I’ve worked on an old gasser. One thing you might check in addition to plug wires, sometimes a new distributor cap can make a difference, and they’re cheap. Especially if water got in there. Maybe pull it and spray it liberally with a water dispersant as a first step. I had a bad cap eat my lunch years ago, I think it had a hairline crack or something that I was missing. Swapped it out last after everything else and it made a world of difference.

Of course an outboard would be sweet on a B20. I really like what John F. did with his B20. But with a Sportsman, it would be probably be good to leave it unmodified if you can get away with it.

Sounds like a good way to start retirement, Just be sure and keep the wife happy with lots of fresh water in the cisterns.

[Rocket]

How wide is the engine enclosure on a Sportsman?

[SteveM]

Rocket,

The width of the opening on the floor is 31".
There is a water dam around it that's close to an inch, so the hood is probably 32-33" in width.

[Rocket]

A V6 or V 8 would fit in there, and i can tell you the 20’ hulls really come alive with the big power and you wind up with really good fuel economy. I think you wanted a mechanical engine for simplicity, but the new electronic gas motors are dead reliable and have caused me much less trouble than carbureted mechanical motors over the years. All I seem to do is change the oil.