Re-powering my seacraft

[infanterene]

Well dropped of the boat today........ Etec 150hp with a 4 blade prop. Hopefully it will be done next Friday. I hope it has similar power to what it had before but with better economy , quieter operation, no smoke and of course better reliability.

[Bushwacker]

Originally Posted by infanterene

Well dropped of the boat today........ Etec 150hp with a 4 blade prop. Hopefully it will be done next Friday. I hope it has similar power to what it had before but with better economy , quieter operation, no smoke and of course better reliability.

Excellent choice - you will not be disappointed! What prop are you getting?

I also considered the same weight 140 Zuke, but concluded that at 122 cu. inches of displacement, it wouldn't have nearly as much mid-range torque as the 155 cu. in. E-Tec! I also like not having exhaust valves to burn out if I run the motor hard! I just completed a 382 mile trip with my 7 year old/450 hr motor, running up to the Long Point Gathering and points north without a single hiccup. Ran with a heavy load with 3 coolers and a bunch of camping gear; burned a little more gas than normal because I spent a lot of time cruising at 30 kts instead of my optimum 24-25 kts, but still only burned about 90 gallons and about a gallon of XD100 oil. Comparison tests on identical hulls have also shown that the E-Tec is actually quieter than comparable 4-strokes at 30 kts because it doesn't have to rev up as much!

BTW, if you haven't already seen it, check out this great web site: http://www.etecownersgroup.com/ . . . Very similar to CSC in terms of the quality and quantity of info available there!

[infanterene]

Not sure. We are going to start with a 4 blade and see how it goes. They have a few props I can try out.

[infanterene]

Well I got my boat back. On the way to the ramp now. I'll post performance number later tonight. Starting off with a loaner 4 blade prop.

[Yz2009]

Can't wait to hear the results

[infanterene]

It was very rough and windy. I couldn't really go faster than 35 because of chop. At 30mph I'm burning 6.5 gph. At 27mph it's like 5 gph. Prop is a 14 1/4 x 17- 4 blade.
I did hit 5000 rpm and backed off, It was hard to read the mph but it think it was either 45 or 47. Still had more to go.

[Bushwacker]

Rene,

It sounds like you are probably in the ball park with that prop if you had more throttle left at 5000 rpm. Your optimum rpm range for that motor is 5500-5600. Step 1 in checking a prop is to make sure tach is accurate, which it will be if you're running an I-Command gage. Step 2 is to make sure mounting height is correct, so you'll need to have someone run the boat up on plane while you take a look at AV plate, the top of which should be out of the water when you're trimmed out and up on plane.

If you can connect your GPS to the I-Command system (or just buy a Lowrance GPS antenna like I did), it will display your instantaneous mpg, which really helps to dial in your optimum trim & rpm, etc. I'm running a 15x15 4B prop and my optimum cruise is also about 27 mph, around 3700 rpm at a little over 6 gph, so you're getting great mileage! With your lighter boat and more pitch, your optimum cruise will probably occur at lower rpm. Denny

[infanterene]

Bushwacker- I have the icon pro gauges with the built in gps for speed. I wasnt able to explore the gauge today but I will tomorrow. Tomorrow is supposed to be a light chop and Thursday will be smooth. I will be able to get a better idea of the numbers in the next few days.

[infanterene]

Ok looks like using the digital rpm gauge I'm only getting 4850 rpm, full of gas and with my wife. Basically that's a full load for me, I weight 300 so I count like 2 people and my wife is about 125.

4850 and 47mph.

[Bushwacker]

Wow, you're over-propped by at least 700 rpm! Surprised that a full tank of gas and extra person made that much difference, but that's why Fr. Frank always says to test props with the max load you intend to carry. You definitely need less pitch; maybe a 3B might be better for you if you want a high speed cruise, but I still think you need some stern lift with a relatively heavy motor on a small boat. Maybe try a 15" pitch 3B Rebel prop, which has a lot of blade area, hangs on plane well and has good stern lift. Too bad we don't live closer . . . you could try my 15x15 4B prop. I can only turn it to 5450, but the optimum rpm for my 2007 motor is 5400-5500. You could probably turn it faster on a lighter boat.

Did you get a look at the AV plate to see if it's dry on plane? If motor is mounted too low, that might get you another 100 rpm or so. Also what was your min-planing speed with that prop? Suggest you send a PM to forum member Keys Cruz, who is also running a 150 E-Tec on an 18 to see what prop he's running. He lives close to you when he's not living on his trawler in the Keys.