repowering question
 

Im considering repowering my 23 with twins, anyone have twins? hows performance. will be puting a bracket on

From the advise I have received on here, the preferred setup is a single large engine. I am sure a more knowledgable member will post more reasons. I went around and around with the same idea on my 23. My wife wanted twins but mostly everyone suggested a large single instead. There is less weight on a single as well as less drag, less fuel burn which I believe could be debatable and the most important idea would be can the boat even get on plane with one of the twin engine inoperable? I understand the appeal of twins from a safety aspect. With technology today I think you could get a hold of seatow about anywhere now a days! At least that was my thinking on it. I am going the a large twin bracket from hermco for the floatation with a single ox-66 250. Luckly I found a good shape 30" motor. I also have a25" motor of the same so If I ended up wanting twins I just have to pick up a 25" mid section for the motor and I can have twin 250's which would be a lot of power all that is needed is to redrill the holes on he bracket! Good luck with which ever way you go! The new Yamaha 300 would sure make hell of a good motor on a 23!

Thanks for the info, we run 70 miles to blue water fish so i'm leaning on the twins for safety, I have a 250 mercury efi right now. The boat runs 46 mph top end but the fuel consumption is not good at all. I am considering the 300 though.

Went from twin 250 yamis to single 250 Zuke and will never look back. The boat performs 200% better with a single.

DAYUMMMM KMOOSE!! Not to derail but how would that run?

Well, you can't run faster than with the single zuke out of the channel so other than short bursts of haul ass and terrifying chine walk at 50 knots.... I guess it ran ok. I actually bought the boat from a friend who had the twins on it for redundency......... and cause it looked cool too. :D

Moose is correct I went from twins to a single, like I bought a different boat. Trim response, performance everything was better. Guys down here run 70 miles all the time, Sea Tow will still get there about the same time and depending on seas tow you faster.

I have twin 115 Suzuki 4 strokes. The boat runs 25.5kts at 4000 rpm's burning total 10.5 for about 2.8mpg. 5950 rpm's runs 38-39kts.(44mph) I love the setup, the weight keeps the ass planted in rough seas, I can keep her on plane at 16.5kts in nasty seas.

Combined weight is about the same as a Single 350 yamaha. Weight is manageable but at or near it's limit. A single 300 is the way to go IMO.

Go with a single 250/300, and despite the value of SeaTow, (of which I am a member and have been since 1984), if you're running 70 miles offshore, put a 10hp kicker on that puppy. After all, SeaTow can break down, too, or be occupied with other assists, and even a little 10 hp kicker will bring you home in 10-12 hours.

Trust me on this. I've been there & done that.
Once ran home on a 15hp Chrysler kicker on the back of a 25' Robalo from Memory Rock north of Grand Bahama across the Gulf Stream to St. Lucie Inlet (62 miles), then down the ICW to Palm Beach Gardens (21 miles). It took 12 1/2 hours, at 90% of full throttle all the way, motor never even hiccuped.

finally pulling the trigger
 

Well i have my boat stripped and ready to start the rebuild process. Im leaning toward a 300 e tec and a bracket. everyone i talk to seems to have the same opion as far as performance. I will post pics as the project evolves. Thanks for all the advice. any comments will be nice

Since I had a 300 V8 single on my Sceptre I want to warn you it will be a real beast, it is only 23 ft and will be very very fast. A 250 would also be fast enough IMHO so forwarned is forarmed. I had the extra hole from the twins so put a speedo in it - it went around past 55 and hit the peg at 0 again - so???? which was quite a ways. The steering gets very light up there too, very light - just say'in

Keep up on your research & make a sound decision. With today's economy, I would go with the 250 etec. The 250 is cheaper & as I understand, the fuel burn @ cruise is much better. It's the same motor, just tweaked. Sure you get a few more MPH at top end but how much time do you plan on running wide open? Forum member "Bushwacker" can chine in here as he is the pro.

BTW: A kicker as backup would be nice but you will be hard pressed planing the hull with twin 150hp should you drop one. (Double trouble-Double maintence costs)
Welcome to CSC & good luck with your rebuild :)

I think I only had mine WOT maybe twice, once in the ICW and once smooth offshore, I raced outboard hyros and it was still scary on the offshore run

With a bracket you'll want the lightest motor possible to minimize the rearward shift in CG. I believe the E-Tec is the lightest 250/300 on the market and BRP has built a great reputation with them, so that would a good choice if a high cruise speed is your top priority. The 250 and 300 are the same basic powerhead, but my experience is that a motor NOT tuned for max HP (i.e., the 250) might actually have MORE mid-range torque, which is what you need to climbing up on plane with a heavy load, or running at min planing speed in snotty conditions. Whichever one you pick, it's very important to have a Platinum certified dealer do the initial setup to properly purge the oil lines and check the fuel supply line for leaks and pressure drop using the BRP test kit. Would also suggest checking out this website if you haven't already seen it: http://www.etecownersgroup.com/post/...e-Shot-6039207 It's the CSC equivalent for E-Tec motors!

Motor height with a bracket can be tricky. In my experience, the old rule of thumb of raising motor 1" for every foot of setback will result in motor mounted too low. You want to be able to see the AV plate above the water when up on plane and trimmed for cruise. Don Herman mounted my 30" bracket at exactly the right height; you want it as low as possible for max flotation, with swim platform just an inch or two above water, which is where mine is. My 25" motor is mounted as high as it can go on the bracket, but AV plate is still under water and needs to come up another inch or so. Am considering adding a spacer plate to allow raising it more. Suggest you discuss bracket and motor mounting heights for the 30" motor with Don.

I went from twin 200 EFI's on a bracket to a single Yamaha F250 on a 4 stroke. I went from hour 850-1300 on it this year and it ran flawlessly. When I am by myself and the livewell empty it jumped right up on plane and was perfect. Would run 28 kts at about 11GPH. As soon as I added 4 people and 40 gallons of water, I had to shift some people up front to get on plane, once on plane there wasn't an issue. but performance dropped to about 26 kts at 13-14 GPH. I can't really keep the boat on plane in anything less than 22 kts. I went to a 4 blade prop, changed pitch, all that stuff.

To echo what Bushwacker said, I did the 1" per foot thing and it definitely put my engine too low. I raised two holes, and I am still debating whether it is too low or not. I have a 30" leg, I am almost thinking I may have wanted a 25". I think I may try raising it another hole before I put the boat back in this year.

All that said, if I had it to do over again, and a few bucks, I would go with the 300 yamaha for sure.

Hey guys....Great talk about the 23cc. I'm new on here and have a 1974 Potter and I live in the North East. I'm just starting the rebuild and my boat had a single evinrude 200 ocean runner carb 25". Sold the motor and all the gear. I'm back and fourth about a bracket or transom # 1 and # 2 engine size. I'm leaning towards a 300 merc verado but from what I'm reading it might be too heavy. I can get a merc or yami because I work for a dealer. I like speed in a cc and after reading all of the great info on here I'm more confused then ever. I'm open to suggestions from the crew on here. Keep up the great discussion guys thank you !!

If you do a lot of offshore in heavy seas max horsepower is not the best way IMO. I've been there and the boat does not want to slow down. If your application is where you can go fast, not an issue but in the rough you and your boat will take a beating. That being said, I've never been in a 23' Seacraft with 300hp on it in those or any conditions.

Not a seacraft but I have been happy with the 250 2 stroke on my 23ft contender.
Its a Vmax injected that was originally 20" motor, I added an extension kit and so far the combo has worked out great.

Boat hits 49 mph on a light load and a 3 blade prop. I plan to try a 4 blade 17p to see if I can get some better cruise numbers.

To all,

Here's a copy/paste of a private forum conversation with a 23' Cobia/Pathfinder owner's results with his four stroke 300 hp Yamaha. I had asked him his performance because of the similar size of his boat to the SeaCraft. Let me tell you, his boat is one step above real nice!!!!


"After break in, I was swinging a 21 Yam SWS-II 3 blade.. Was a little tall, and only hit 5800 rpm light. It was square, meaning 3500 rpm was 35 mph (and 4.1mpg) and 5800 was 58 mph. But, I didn't want to load the boat and lug the motor. The 19 pitch hits 6000 rpm, but loses some speed and economy.. It s the best prop, and with the SDS, shifts silently.. Very cool to have a silent boat around a pod of Sails or Dolphin !

Numbers with a standard load and the 19 pitch prop:
Like all boats, there is a best-economy rpm, which is 3300, 29mph, @ 3.8 mpg. The 'Happy' rpm is 3900 at 35mph @ 3.2 mpg. WOT is 6000/55 mph @ 2.0 mpg. These numbers are in a light chop.

We spent 9 days in the Keys this July. We filled the boat up and fished, ran offshore, trolled some, spearfished out by the reef and buzzed around with the girls.. We burned a total of 71 gals and ran 230 miles. Total trip avg of 3.2 mpg.

The F300 is strong, quiet and a good example of why you max the HP on an offshore boat. I think it would be an excellent repower for the 23 Seacraft.. Even the F250 Offshore would be excellent, and maybe less money. The older F-250B's are rock solid motors as well. Depends what $ you have to spend.

One note.. I would measure the cut transom width and check the swing of the steering on the engine cowls. There was one model with a pretty small cutout.."


Still, if it's me and looking at the $2,000 to $3,000 difference with the 250 eTec versus the Yamaha......I'd go with the eTec.

Thanks for all the feed back. Im leaning toward the e tec 250/300. I am putting a bracket on and going from there. All I can say is these boats are great. Ive fished a 70 mile run for three years and my seacraft has always brought me back safe. I cant wait to redo her and get back on the water.

That's a pretty high min planing speed, so I'd guess you're fairly stern heavy, although I would think a 23 would be less sensitive than a 20 to the CG shift caused by a bracket. I'm surprised you can't plane slower with a 4B prop unless it's a bow-lifting prop like a bass boat would use. Are you using trim tabs, because that also helps?

Would be interesting to know what the min planing speed is on a 23 CC with a light 2-stroke motor on the transom for comparison. I think Potter put more deadrise in the outer panel of the 23 compared to the old Moesly 21, which would plane at about 12 mph with a V-8 Mercruiser; that relatively flat outer panel provides a lot of lift, so increasing deadrise on it would tend to reduce lift and increase min planing speed.

My boat is also stern heavy with a 30" bracket and 427 lb motor. I also had a 22 kt min planing speed until I went to a stern lifting PowerTech 4B prop, which made a huge difference, allowing me to hang on plane at 12-13 mph, even with a very heavy load. That's what I could plane at with a 300 lb motor on the transom and not quite as much load. I've had trim tabs on the boat almost the whole time I've had it and they also help you plane at lower speeds. A Doelfin or equivalent will also give you some additional stern lift to reduce planing speed, but it adds drag and appears to reduce my fuel mileage by about 0.2 mpg, although that's not a bad trade when the seas get really rough!