21 Seacraft repower advice?
 

I have an 02 21 with a 225 optimax. The hull really frees up above 30knts and ride best in a stacked bay chop around 35-38 knots. 225 tops out around 39-40 knts. Would like to be able to run at 35knts 4500-5k rpms. Thinking 250-300 Yamaha or Zuke. Yamaha is only 60lbs heavier and Zuke 80-100. Only time I pull it back under 35knts is when sea conditions cause prop to come out of the water. Don't want to stress a new motor running on the pin all the time. Any suggestions on wether the transom will handle the torque of a 300? Need advice thanks

All I know is 225 is the max HP stated for that boat....I tried looking at your numbers to mine... I run a 200 new Optimax with a stock alum prop...
3600=24k
4300=32k
4600=35k
4700=37k
5000=39k
5300=40k
that's with 2pl and 30gal w/ttop....one thing be certain to check clearance for any motor not much room in the well side to side or tilting up.. I had to move my harness and cables ...I am still playing with mine as to prop,, trim,, etc .. I only had the boat for a few months....would like to see if any slackers on here have input on your post..

Joe R.
21 SeaCraft
1998 w/ 2015 200 Optimax
Susie 2

Joe my #s are pretty similar to yours, 200 HPDI...

Hey Capt Chip,
Welcome to the fray. Not sure how old or tired your Optimax might be but Capt Obvious here to suggest you get w/ Joe and compare notes on motor elevation and Prop. Sounds like Joe has some variant of the Black Max prop. Excellent, inexpensive all around choice for these hulls.

What prop (be specific, make/model diameter & pitch) are you using, and how high above your keel is your anti-cavitation plate, while parallel to keel.

Find out how your set up compares to Joe R as he's getting the numbers you seek with 25 fewer ponies, granted he's got the new Opti...

Might find what you're looking for for a while without dropping 20k.

Joe
Your numbers sound great especially with a 200. I just bought the boat with plans for repower. My motor only has 230 hrs, not sure on exact height but looks and feels right, cavitation plate is out of water on plane. It's swinging a 19 stainless mirage prop. Since I asked the question I have found no dealer that will mount a motor over 225 (that's what the boat is rated for) and if I just buy it and hang it myself, no warranty. So I'm back to a 225 or 200. I'm gonna put a Yamaha on it due that I've always had great success with them in the past. So now I'm between the 4.2 literv6 225 or inline 4 200. I think the torque difference in the 4.2 over inline 4 will be huge. I can't turn the wheel with optimax trimmed up now. I've got a 6" bobs machine jack plate ordered so hopefully that will help some. The new 4.2 is 60lbs lighter and narrower than old 3.3 Yamaha. 4.2 225 Yamaha is where I'm leaning now. What's your thoughts?

FYI - they reduced weight while increasing displacement on those newer 4-strokes by eliminating the cast iron cylinder liners! That means they're a throw-away motor if you ever encounter a fuel starvation situation that leans out a cylinder and scuffs a piston! Might be worth checking out a "225" G1 E-TEC that's 240 hp at the prop with even less weight. Consider the HO model if looking for top end power or the standard model if you want the most mid-range torque.

Ditto!!!! Denny speaks the truth! The 225 eTec will run circles around a Yamaha.

Yamaha is very, very proud of their product! Their over priced $$$$ issues is killing them with the re-power group, which they could care less about. Notice the Suzuki following is growing like crazy. Keep in mind Yamaha's main focus is the new boat manufacturers, us little re-power folks are just bottom feeders that provide little profit or revenue.

I know that's a little rough....but it's fact.

The pink pantie dropper is correct. yammi bought every transom they could. They also
bought many brands. Many.

My `89 20 is factory rated for 235. Orig. data plate.
Go to a trophy shop and get a new one made.
My original transom is 2 3/8 at 25".

My brother just put an 08 etec 225 on his Mako 221 at 2600lbs and is very happy.
Replaced yami ox 66 250.

Torque baby.

Slacker out

If it was a 2 stroke that would be more of an issue but internal piston oiling on a 4 stroke pretty much eliminates that issue as many car motors for decades turn fuel and spark off to cylinders to improve fuel economy. It's not an issue and it wouldn't surprise me if Evinrude makes a move in the same direction to reduce weight down the road.

Chip, Yamaha makes great motors that are inherently reliable but at a high price tag. I wouldn't hesitate a bit if you want to go with the Yamaha as plasma coated, non-iron cylinder linings are not some brand new technology that came out yesterday and have also not been problematic with engine manufactures that use them to lighten all kinds of motors including Yamaha.

I find it quite amusing to see the level of Yamahatred on all the boards but for the most part it is non-Yamaha owners that raise the most concerns. I'm quite surprised GFS hasn't started with the F350 flywheel rant yet. :D

Hold on Big guy - GFS and I are not done with -
Elgin water pump driven bilge pumps,
Eska shear pins
Sea King motor mounts
Martin throttle grips
Homelight Bearcat prop selections
Keikhaefer Hurricane coils

So hold your horses, we'll get to those saber toothed frisbees soon.