Re-powering 1972 SeaCraft 23'...F300?

[Riley@florida-re.com]

I enclosed the transom and am running the same 30" Armstrong bracket with a 300 Yamaha 4 stroke. The boat runs 50 WOT and loaded burns 2.8 - 2.9 MPG. I ran it from Ft. Pierce to Walkers Cay / Rosie's Place in grand Bahamas this past weekend and had a glass crossing on the way over. I burned 42 gallons in 118 statute miles getting there = 2.81 MPG. On the way home the bank was windy and 2 - 4 where I could only run 20 knots. When I hit the stream it flattened out and ran 38 knots to make up for lost time and burned 50 gallons at the same distance = 2.36 MPG. Overall the boat is unreal! runs perfect and is very well balanced. The scuppers stay dry even with three guys standing on the bracket.

I have no idea about the etec. I am just happy that I do not have to buy the excessive oil at $40 a gallon.

[DonV]

Very nice numbers!!! 2.81 mpg is only double what I get, which if you do some Jethro inspired math that's half as much $$$$ as I would "burn"!!!

[fly4navy]

Right! You don't have to buy the $40 a gal. oil with the E-tec, but you give the same $$ and more to the dealer when you get the oil changed and after you have been burning dirty oil for 75% of the oil cycle. The E-Tec is always burning 100% virgin pure clean oil in the combustion cycle...and I like that!

Originally Posted by Riley@florida-re.com

I enclosed the transom and am running the same 30" Armstrong bracket with a 300 Yamaha 4 stroke. The boat runs 50 WOT and loaded burns 2.8 - 2.9 MPG. I ran it from Ft. Pierce to Walkers Cay / Rosie's Place in grand Bahamas this past weekend and had a glass crossing on the way over. I burned 42 gallons in 118 statute miles getting there = 2.81 MPG. On the way home the bank was windy and 2 - 4 where I could only run 20 knots. When I hit the stream it flattened out and ran 38 knots to make up for lost time and burned 50 gallons at the same distance = 2.36 MPG. Overall the boat is unreal! runs perfect and is very well balanced. The scuppers stay dry even with three guys standing on the bracket.

I have no idea about the etec. I am just happy that I do not have to buy the excessive oil at $40 a gallon.

[DonV]

Ya know I've never thought about it in those terms. I've got a Yamaha four stroke and a Merc two stroke and even though I use Amsoil 100% synthetic in both I just never thought about the 75% of the engine oil life before in a 4S. Good point! FWIW.....I get my Amsoil HP 100% synthetic two stroke for $32 a gal delivered to my door. It can be used in the eTec at the same computer setting as the Evinrude 100XD.

[Andy]

If I were to compare the weight of your 23 ft Secptre to a 1973 23" Center Console that I have recently cdone a complete restoration on using Divinacel and cloeed in the transom. I imagine the center console would be 300-500 lbs lighter. I am also going to use a 300 Yama and trying to guess the speed and fuel. Might be similar to yours accept for any weight difference.
What do you think.

[FAS]

Yamaha..,earlier 2 stroke EFI OX66, or newer 4 stroke.if it cost you alittle more for service, its worth it... imho