New Engine - for 2001 20 SC MA - part 2

[fishstu]

I am still on the fence weather to go with a 115 hp 4 stroke or 150 hp Etec.

Trying to figure out what specifications and aspects of new engine should be prioritized in my desc ion making - I am going to have this engine for a long time.

Questions ?

Etec has a 8 year warranty offer that ends June 30th - which means to get that I have to make decision in a couple of days - what value , importance do folk put on that do.

the lighter the weight on the transom the better with 300 lbs as a target weight is is talked about a lot, which i understand fully.

I have a 2001 mercury EFI on it now 425lb

Engine weights listed


Brand HP Type Dry Weight Weight diff
Mercury 150 2 stroke 425 0

Mercury 115 4 Stroke 359 -66
Mercury 115 4 Stroke 363 -62
Mercury 150 4 Stroke 455 30

Yamaha 115 4 Stroke 377 -48
Yamaha 150 4 stroke 491 66

Etec 115 2 Stroke 390 -35
Etec 150 2 Stroke 433 8

My question is how much difference does every 10 lbs make on the transom ? The mercury 115 hp Command trust 4 stroke at 362 lb is 62 lbs lighter than that the engine coming off for low planing speed. Would the heavier Yamaha 115 hp 4 stroke at 377 lbs with a difference between the Merc 115 of 15 lbs be noticeable , or the 33 lb difference between the Etec 115 and Merc 115.

My concerns are that 115 might struggle with 5 people on board.

The boat has trim tabs and I had fitted a Permatrim trim fin the existing Mercury 150 2 stroke that helped a lot with getting on and keeping on plane. I would fit one to my engine.

I am trying to get a feel of the difference in fuel consumption between the 115 4 strokes and the etec 150.


Thanks

[Old'sCool]

Why not consider Optimax?

[Bushwacker]

I frankly would not recommend the 115 E-TEC because it's gained so much weight that it's not really that much lighter than the 150. (I think they're now using the V-6 lower unit.) It also has the 2-position exhaust valve which adds complexity, and the V-6 is a bit smoother at low speed with 2 extra cylinders. With comparable loads, I don't think you'll see that much difference in fuel burn between the two motors, since the V-4 will be running with more throttle opening. The V-4 is a more "souped up" motor with higher HP/cu. in., so it tends to be a bit peakier, and comes on strong about 4000 rpm when the exhaust valve switches to the shorter exhaust passage. The V-6 has a flatter torque curve, so it's pretty happy between about 3200 rpm on up to WOT, although it feels like it's nearly vertical between about 1800 and 3000 rpm when it's switches to the very lean stratified charge mode to the homogeneous mode. It's sweet spot and peak torque is about 3700-3800 rpm at 27-28 mph and 6.5-7.0 gph. Tried attaching the torque curve pdf file to this but it's too big; if you pm me an email address I can send it to you.

Capt. Terry ran a couple of 150 Mercs on his Seafari before going with the E-TEC, so he can give you a good comparison with your current motor. Since likes to wake board at about 3000 rpm or less, he might even say that the E-TEC almost has too much torque! If you like the performance with your current motor, you may be disappointed with the lack of torque of the smaller motors.

[Terry England]

Originally Posted by fishstu

.......

My concerns are that 115 might struggle with 5 people on board......

Thanks

He's one struggling a little pushing an old 25' x 10' - 6,000# Moppie hardtop 20 miles an hour. I wanted to see if just one even would plane the boat off. They are the 25" motors (2.25 to 1) and I'm running 15" X 15" Mercury Inertias. Teamed up they manage to get that "slug" up to 37 mph at 5600 where my fuel burn rate goes down to 1.5 MPG. I have about 500 hours on them with no issues.