ETEC 90: Poor Motoring Performance

Bobby T.-26X #4767 · Post by **Bobby T.-26X #4767** » Fri Apr 27, 2007 6:37 am

beene wrote:I am still thinking with rpm range to be from 4500-5500 my 75 is beetter sooted to the 13 but I really have no idea till I try it out.

hey! 13 pitch is fine. i generally tout an 11 pitch pontoon prop because a couple of Macs that I know (one X and one M) have used a standard 13 pitch with a Tohatsu 90 and their RPMs barely get to 5200 at WOT under normal loads.

but, the Etec powerhead is a different animal. so if a 13 pitch get you the results...go with it!

the main thing is that you're not lugging the motor with a 15 or 17 pitch.
these Macs are a heavy load even for a 90hp.

Bob T.
"DāBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

beene · Post by **beene** » Fri Apr 27, 2007 8:24 am

Thanks again Bob

I will be sure to let you know what my testing shows.

Cheers

G

Mac Ziggy · Post by **Mac Ziggy** » Sun Apr 29, 2007 4:05 pm

Did some more check out runs today on the ETEC 90 on the M. Had four on board this time and have added the sunshade. Filled the ballast for the first time. Still no mast or rigging.

Handling was a little stiffer with the ballast full.

Most speeds at the different RPM ranges were about 2 MPH less than before. Didn’t seem to make any difference at 3000 to 4000 RPM’s though. WOT is 24 to 25 but the RPM's are right on 5500, which is the top of the recommend range. I was hitting 5800 RPM’s before and was a little worried. The prop is the Evinrude 14 X 11 made for pontoon boats. So far it is giving just what I wanted. I would rather have SS but not if I don't get the same results.

Another motor with different gearing might give different results.

Still had the M splash in the 20 to 22 MPH range. Got to put some kind of baffle in the dagger board slot. I think it is caused by the Bernoulli effect.

Bobby T.-26X #4767 · Post by **Bobby T.-26X #4767** » Sun Apr 29, 2007 9:21 pm

you are there! right where you wanna be.

delevi · Post by **delevi** » Mon Apr 30, 2007 12:12 am

The prop is the Evinrude 14 X 11 made for pontoon boats. So far it is giving just what I wanted. I would rather have SS but not if I don't get the same results.

Still had the M splash in the 20 to 22 MPH range. Got to put some kind of baffle in the dagger board slot. I think it is caused by the Bernoulli effect.

You will probably go faster with 14 x 13.

To avoid the splash from your DB well, try lowering the board about 2 inches. You have 2-3 inches of empty space before the board comes out of the bottom of the hull. This will most likely eliminate the problem... says so in the Mac manual, however, I only experienced one splash since I've had the boat.

sorcha · Post by **sorcha** » Mon Apr 30, 2007 11:49 pm

Finally had bombardier look at my engine.The mechanic found something in the software of the engine that he was able to change and apparently increase the power by about 10 percent.All else was ok but did change to an evinrude 3 blade 13 3/4 by 13 SS prop ...part no 392261..HE also found my tacho was under-reading by 300rpm..Now top speedis 22knots at 5100 rpm but the cruise at 16 knots at 3500 or 18 knots atjust under 4000 rpm feels very solid and comfortable..I suppose all I was ever trying to achieve was a comfortable cruise at 16-18 knots without running close to WOT...and the boat is now doing this..THANKS ALL.

Mac Ziggy · Post by **Mac Ziggy** » Tue May 01, 2007 5:39 am

sorcha,

Glad to see you back with good news. 22 knots is about the same as the 25 mph I am seeing on my M with the 90 ETEC. I have the 14 X 11 prop. I am quite happy with the speed and the power. I am reading about 5500 rpm on the tach. That can vary slightly and be caused by different things.

Get back on the water and have some fun.

CPT Haddock · Post by **CPT Haddock** » Mon May 21, 2007 5:55 pm

I installed the stabilisor fins on my etec 50, I am pleased with the result which is smoother turns at high speeds, I found the boat tippy ie leanded into the turns and felt uncomfortable now it turns smoothly without the tipping feeling.

Mac Ziggy · Post by **Mac Ziggy** » Wed May 23, 2007 6:36 pm

CPT Haddock,

I installed a hydrofoil on my Etec and I can see where I'm going now. The boat never really planed before and I could not see around the bow. The engine doesn't work so hard and I'm sure the fuel consumption is less.

At wot the rpms are about 5800 now. More weight may bring that down. I like the 4500 to 5000 range and speed better for cruising anyway.

Boblee · Post by **Boblee** » Wed May 23, 2007 8:15 pm

Re the hydrofoils, I am sure I read somewhere that they weren't recommended for the Macs.
Only problem I have had with my 50 ETEC is that it seems to run a bit rough if kept at 1200 and even 2000-3000 revs constant for long periods.
I think from memory my speeds are about the same as others here but will be checking it out again soon and will be trying out a couple of different props.

sorcha · Post by **sorcha** » Mon May 28, 2007 3:06 am

just a question to MAC ZIGGY..Is it worth fitting a foil to the outboard because the bow is very high and making visibility difficult.How much effect does it have and what does it do to the performance? THANKS.

beene · Post by **beene** » Mon May 28, 2007 4:34 am

Sorcha

Check out my videos and tell me if you think my bow is high. I can go from 0-max cruise with no bow up attitude at all. From the Capt chair, sitting down, I can see clear over the top with about 2 inches left to the horizon line. If I trim up at all, the bow comes up, splash pattern changes drastically becoming far more outward, speed drops, engine sounds unhappy, can't see over the bow without standing up, etc.

VIDEO

G

Boblee · Post by **Boblee** » Mon May 28, 2007 6:14 am

Hey beene whateverv you are doing it seems to be working, maybe I better trade my 50 etec in on a 75.
No way can I get anywhere near that sort of plane.

Mac Ziggy · Post by **Mac Ziggy** » Mon May 28, 2007 6:33 am

Sorcha,

This is my post on beene's thread.
http://macgregorsailors.com/phpBB/viewt ... 0&start=30

Also check out deja_vu's thread on the wedges.

http://macgregorsailors.com/phpBB/viewtopic.php?t=7894

The foil makes a great difference. I can sit down and see over the bow. The engine does not work as hard and runs at lower rpm. The foil was easy to install but I would rather have had the wedges. Either way, I think the boat is safer when you can see where you are going.

I purchased the engine separate form the boat, so the engine dealer was not familiar with the boat and did not want to suggest changes to it. The foil was an easy installation - about 20 minutes. That's after a couple of days agonizing over drilling holes in my motor.

I think the wedge is a better permanent solution. The foils showed me the problem could be fixed.

I am having some trouble with the starter, so the boat is at the dealer's now ( I think my daugher running it out of gas when I was not on the boat had something to do with that). I didn't take any pictures but I got a white foil and it looks good on the engine.

As I have said, I like my boat, I like my engine and I think they make a very good match. Good luck

sorcha · Post by **sorcha** » Tue May 29, 2007 12:44 am

Thanks I went out and fitted a foil today and it has definitely pulled the bow down.ANOTHER QUESTION ...where is your sacrificial trim .anode under the cavitation plate positioned..<left or right >Im having trouble with the boat trying to turn to the right..and was wondering where it needs to be.

MacGregorSailors.com

MacGregorSailors.com

ETEC 90: Poor Motoring Performance

Hydrofoil stabilisor fins