those are close to the speeds I was getting with the F225. I think your 300 should be getting better numbers; could be the prop or engine height. Either that or your boat is super heavy :o

I was about 22 knots at 4000 RPM with the F225, which is barely really a 225 hp motor.

I have a rebuilt 2005 300 on a bracket on my 23. Picked the boat up in June . I do not know exact burn rates but I do see 35 mph on the gps at 4000 rpm . Will get real close to 50 at wot. This power seems to be about perfect for this hull .its a 85 model by the way.

thats helpful, and pretty good

how about inexact burn rate :)

Me too - might want to look at:
1. the boat - is it water logged and therefore much heavier than spec
2. is the engine too low
3. is it prop'd right, getting max rpm, and trimmed out when testing full speed WOT

Would think it should run the boat to at least 55 mph.

I'd personally look into getting a Suzuki 300 for that boat. You can find good deals out there if you were willing to purchase used also. My buddy picked up a 2009 Suzuki 300 with hardly no hours on it and still under warranty for under $9k for his 25' Contender. Motor was practically brand new and runs like a champ!!!

Shine, if money were not an issue I would think about a f 350. I believe they are lighter then the older f 300's.
As for burn rates for my 300 hpdi. I would guess in the 2 mph range. The little bars don't help much and I just put more gas in when it gets low.
I am only getting about 5500 rpm's at wot. I haven't looked up what is ideal but think I could do a little better. Will probaly call ken at prop gods next spring and do some fiddling. Think I can improve cruise and top end a bit.
Chip

Im going to have to disagree on the Yamaha F350. That engine is entirely too heavy for the 23' Seacraft. Not saying that you couldnt put one on it, but I think its going to be too heavily weighted in the back. The best single engine for this boat is the Yamaha F300. It is actually the lightest engine of its size out there right now. My friend has a Mercury Verado 350 SCI on his 23' Seacraft right now, and he said the engine is too heavy for it weighing in at 667 lbs and he is using a double floatation Armstrong bracket for it. Says the boat needs lot of trim tab to keep the bow down. He said if he were to do it all over again he would go with the Yamaha F300 any day.

Here are the comparison specs.

Mercury 350 SCI ..... 667 lbs
Mercury 300 Pro ..... 20" ... 635 lbs (website notated lightest model, so Im assuming the 20" shaft)
Mercury Verado 300 ..... 20"...635 lbs (website notated lightest model, so Im assuming the 20" shaft)
Yamaha F350..... 25".. 804 lbs......30".. 822 lbs
Yamaha F300..... 25".. 562 lbs......30".. 571 lbs
Suzuki 300 ...... 25".. 604 lbs ..... 30" .. 615 lbs.

http://i141.photobucket.com/albums/r73/PharmD2B30/6.jpg

Correct....you don't want the Yami 350 hp which is a V-8, it's a heavy ass motor that's in love with gas.

Don't forget about the 300 E-Tec! It's actually the lightest at 528/534 lbs for 25"/30" versions!

Ahhh..... Yea, I always seem to forget about the E-Tecs.....great motors there too!!