repowering question

[Briguy]

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.

[Fr. Frank]

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.

[dave law]

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

[eggsuckindog]

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

[ct9amr]

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.

[DonV]

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.

[Capt Chuck]

Im leaning toward a 300 e tec and a bracket

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

[eggsuckindog]

Originally Posted by Capt Chuck

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.

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

[Bushwacker]

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.

[dave law]

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.