Etec 50 hp, what prop for top speed?

[danboltonnewby]

:macm:

Can anyone advise me what prop size I should be using to get max top end speed with my Etec 50 hp?

Currently with a 3 blade, 13 pitch, getting 16 mph max at WOT.

This is in Lake Couer d' Alene, (fresh water) at an elevation of 2128ft, no water in the ballast tank, 2 people onboard and about 200lbs of gear.

Does anybody have the same engine with a different prop?
Does anybody have the same engine and get 20 mph?

I really hope to get the boat to go 20 mph with the 50 hp... or am dreaming, should I be thinking of more hp if I want more top end speed?

Any help would be really appreciated...

Hope the summer was kind to the fleet...

Brgds

Dan

[kmclemore]

Dan, I'd advise you to use the "search" feature in the menu under the advert at the top of this page.

On the Search page type in "etec prop" in the top box, click the "Search for all terms" radio-button and then hit the "Search" button at the bottom of the box. You'll find **LOTS** of ETEC prop related threads!

[Bobby T.-26X #4767]

a 10 or 11 pitch with big dog ears (large surface area) offers the best speed solution for your Mac.
that said, in your situation you may be expecting to much out of the 50 Etec. in fact, all newer technology 50hp motors will not get you to your speed requirements with your suggested load.
that is, newer motors, although cleaner burning and more fuel efficient than their predecessors, are much heavier and offer less torque than the smokey & reliable 50D-2 stroke Tohatsu of the 90's. now that motor can just plain fly. however it eats the fuel, is loud as hull, and is no longer availble as a new purchase.

you have a very common complaint of a Mac owner who purchased expecting the 50hp to push a loaded boat to the advertised speed of 22mph. it just does not happen unless you weigh 150#, while stripping the gear and passengers out of the cabin & cockpit.

to get where you want to be you'll need to upgrade to a 70/75 or 90hp. that's a fact!

Bob T.
"DaBob"
'02X w/ '04 90-TLDI & '06 2.5-Suzuki

[DLT]

I use a 3 bladed, 14" diameter, 9 pitch old style pontoon boat prop.

Its on the low end for pitch, even for a 40. But, I'm usually rather heavily loaded, so... Even then, though, its on the low end, which means my RPMs are a little higher than I'd like.

I'd prefer to have a 10 pitch, but they don't make them. I have not had good luck getting a prop shop to make a 10 pitch out of something else. Maybe because I won't let them touch my 9 pitch. I've had them rework newer style 11 pitch props, but the improvements weren't that good...

So, my advice to you is to get a 3x14x11, in an old style. I suggest an 11 pitch, since you have 10 more HP than I do, and therefore a 9 would be wa'ay too low. Don't let the guy behind the counter convince you that their new blade style is better. It may be for some boats, but not ours.

Ohh, and NO cupping! The prop they will want to sell you will likely be heavily cupped, because thats what they do now. But that's not what you want.

Finally, as mentioned before, get a big dog ear'd prop. The bigger, fatter the blades are the better... This ain't a bass boat. This is a big, heavy, inefficient hull for a 50hp motor.

Now, don't get me wrong, I love my boat, and am not trying to bad mouth her. But, understand that this is a compromise boat, that has sacrificed efficiency in both power and sail modes in order to be able to provide both power and sail modes...

[aya16]

DLT is right. the etech 60 around here are moveing 13 inch pitch blades with good results so your 50 should work good with a 12.
whats your rpm with the 13 at 16mph?

and horse power is the only way to increase speed as much as we all want. if its important to get that 22 mph then beg borrow what ever to get a 90 2 stroke 1989-2004 anything, like a merc. They weigh less than a 4stroke 50 or what Im going to do get an etech 90.

In your case you would have been better off if the dealer put an etech 60 on your boat instead of the 50. The engines are identical in everyway except hp. Those thinking of the 70 check the brand of engine you want close. If the seventy is a de-tuned like most are 90 than pop for the 90 you will not regret it. you will have the power and you may never use all of it but your engine wont have to work so hard.


anyone buying a mac please do yourself a favor always go for the bigger
engine. Merc bigfoot 50 is exactly the same as a 60, etech 50 exactly the same as the 60 yamaha the same. Suzuki is the odd ball.

Now on the etech 50 I dont know what evinrude did to make the 50 a sixty
but if its just a tuneing thing you might be able to upgrade. But im not sure. And if you asked 5 diff. dealers what they did Im sure you will get 5 diff. answers.

[aya16]

heres some numbers I worked out


etech 90 weighs 320 lbs
suzuki 50 4 stroke is 243 lbs
77lbs diff (More)

etech 90 320
bigfoot 50 264
56lbs diff. (more) you can toss your little kid over board and make up that weight.

suzuki 60 4stroke 385
etech 90 320
whopping 65 lbs (less) then the suzuki

yamaha same as the big foot

[Gazmn]

You know I was just going to write in a new subject [ & perhaps I will still.] But I'm replying here because I believe my issues are related. I put the 90 horse etec on my old '97. I'm not breaking 17 Kts with a 14x13 aluminum prop.

I was a bit dismayed that with ballast in and out I'm maxing at 4500 rpms.

In short, I'm going to try a 14x10, which may not increase my speed but pick up my rpms.

advertised 24 mph my @$$.

P.S. will also weigh my boat when I pull it next weekend; but I guess loaded she's 3300 W/o ballast.

[Bobby T.-26X #4767]

that doesn't make sense because the Etec and Tohatsu 90 both push a Mac equally. and, actually, a 13 pitch should get a lightly loaded X to 30mph without a problem. the only issue with the 13 pitch is that your RPMs at WOT isn't where the manufacturer desires (6-700 too low).

an 11 pitch (14"), big dog ear, pontoon prop should work fine. with it you'll get to the top RPM range and max out at 22-23 Knots (26mph). plus your motor won't lug.

however, you may have something else going on like a bad/clogged cylinder. that means you may be getting your current speed with two (rather than 3) cylinders.
wouldn't be the first time this has happened to someone.

Bob T.
"DaBob"
'02X w/ '04 90-TLDI & '06 2.5-Suzuki

[DLT]

I was a bit dismayed that with ballast in and out I'm maxing at 4500 rpms.

Shouldn't your max RPM be MUCH higher, like 5500?

[aya16]

90 etech same rpm ballast in or out? taking a thousand pounds off any boat will boost the rpm up alot. Maybe your computer is set to redline at
4500 no matter what.

1 there is something wrong with your engine to only get the same speed as a 50.

2 the prop you have is a 15-17 pitch I wouldnt even try a 10 inch on a 90

3 well..

[Bobby T.-26X #4767]

here's what a 14" x 11 pitch prop with big dog ears looks like...





BTW...max RPM for a 90 hp ETEC is: 5500

90 specs

you need to be there and you will with an 11 pitch. if you are not, then there are mechanical issues to consider.

[aya16]

Bobby are you running an etech 90?

[Bobby T.-26X #4767]

Bobby are you running an etech 90?

no, i'm a tohatsu 90 tldi.
rpm's are nearly the same and both use a 14" prop.

others on this board who run a 90 etec have suggested an 11 or 10 pitch.
i use an 11 pitch on my tldi.

a mac is a heavy boat for even a 90hp motor. therefore, you need a lot of spin and the ability to grab and push water. thus, a pontoon style prop is suggested.

that way you can max both rpm's and top end speed.

Bob T.
"DaBob"
'02X w/ '04 90-TLDI & '06 2.5-Suzuki