|
New E-Tec Pulls Hard Right
|
| simontonmc |
Posted on 10/24/11 - 10:29 AM
|
Member
Personal Page
Posts: 25
Comments:
0
Joined: 08/15/11
|
Yesterday I water tested my new 90hp E-Tec repowered on a 1979 17' Montauk, The pulled dangerously hard right particularly in the 2-4k RPM range. It was nearly impossible to turn left. The engine is mounted 3 holes up and we were testing with Evinrude Johnson 17 and 15 aluminum props. We adjusted the trim tab with not a lot of improvement. Any thoughts on what might be the issue or ways to improve handling. Do I need to consider adjusting the tilt pin(?). I think it is currenly in the 2nd position. Top "row" of holes closet to the transom. I do not have hydraulic sterring.
|
| |
|
|
| CES |
Posted on 10/24/11 - 10:55 AM
|
Member
Personal Page
Photo Albums
Project Albums
Posts: 2681
Comments:
7
Joined: 04/27/07
|
Sounds like you might need to trim the motor up a little once you get up on a plane. Typically when you're on a plane, you want to trim it so there's next to no pull to the right.
No real need to mess with the trim tab and it should be located slightly to the right of center line as looking forward with the prop in your face.
Edited by CES on 10/24/11 - 11:38 AM
Cliff
1966 13' Sport with a 1993 40hp Yamaha 2 Smoker |
| |
|
|
| Tom W Clark |
Posted on 10/24/11 - 11:14 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
I agree, you are not trimming the motor out at all. A standard rotation outboard will pull to starboard when trimmed way in and will pull to port when trimmed way out as the result of asymmetrical loading of the propeller blades. In 1979 there were no mechanical NFB steering systems so you really feel the pull.
The tilt pin should be in the 1st position, closest to the transom. With power trim and tilt there is no reason to limit the range of trim with the tilt pin.
The trim tab should be set with its trailing edge to starboard about 25-30 degrees.
If the motor is mounted "three holes up" then it is mounted as high as it can go with the mounting bolts going through the lowest of the four sets of bolt hole in the motor. Is this correct?
|
| |
|
|
| simontonmc |
Posted on 10/24/11 - 11:36 AM
|
Member
Personal Page
Posts: 25
Comments:
0
Joined: 08/15/11
|
Tom you are correct. See my personal page for a quick picture of bracket.
|
| |
|
|
| Tom W Clark |
Posted on 10/24/11 - 11:38 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
Yes, very good; it is as high as it can go.
You'll want the 17" BRP/OMC prop.
Trim the motor out as far as it can go the next time you test the boat. You will begin to understand propeller torque.
|
| |
|
|
| CES |
Posted on 10/24/11 - 11:39 AM
|
Member
Personal Page
Photo Albums
Project Albums
Posts: 2681
Comments:
7
Joined: 04/27/07
|
I think it's a trim issue..... As Tom mentions, trim the motor up until while underway until you feel only a slight right pulling tendancy.
Cliff
1966 13' Sport with a 1993 40hp Yamaha 2 Smoker |
| |
|
|
| Joe Kriz |
Posted on 10/24/11 - 11:44 AM
|
Site Owner
Personal Page
Personal Album
Photo Albums
Project Albums
Posts: 11447
Comments:
452
Joined: 03/18/05
|
One thing about the trim tab on the motor...
This tab is for one reason only, to obtain the same steering force in either direction when trimmed out at your normal cruising speed.
To check this, get at your normal cruising speed and turn the wheel port and starboard. It should take the same force to turn the wheel in either direction. If not, adjust the trim tab to achieve this.
If you have hydraulic steering or no-feedback steering you will not be able to notice this as much as you would with regular steering.
|
| |
|
|
| simontonmc |
Posted on 10/24/11 - 11:49 AM
|
Member
Personal Page
Posts: 25
Comments:
0
Joined: 08/15/11
|
Any thought on being 3 holes up vs. 2 holes up? I was getting about 5,100-5,200 RPM with the 15 prop @ WOT. Engine seems awfully far off the transom as you can see in the picture. Cavitation plate is probably ~2" above keel.
|
| |
|
|
| Tom W Clark |
Posted on 10/24/11 - 11:53 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
The only reason you would lower it is if it were ventilating excessively.
If you were not trimming the motor out during your WOT testing, then your RPM and speed will both be much lower than they should be, which would explain all that you report.
I guarantee you a 15" aluminum prop is too short. Try the 17", trim the motor way out and see how fast it can go and at what RPM it does so.
|
| |
|
|
| simontonmc |
Posted on 10/24/11 - 12:00 PM
|
Member
Personal Page
Posts: 25
Comments:
0
Joined: 08/15/11
|
I did trim the engine out to achieve the 5,200 RPM and sterring was better at the higher speed. Tom, I'v seen you recommend the Stiletto 13.25 X 15 Advantage for a 17' Montauk. Why would you say I should go with the 17" here instead? Does the aluminum vs. stainless play in to that decision? Although I probably didn't have the appropriate trim level during testing, I was only getting 4,700-4,800 with the 17". so thought it made sense todrop to the 15". Thanks for all the input.
|
| |
|
|
| Tom W Clark |
Posted on 10/24/11 - 12:05 PM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
I don't believe you trimmed the motor out very far. If you had trimmed it out as far as it can go it would start to pull to port (left). Do you have a photo of where the trim tab is set now?
I recommend the 15" Stiletto Advantage because it will yield about the same RPM as the 17" OMC/BRP props, both aluminum and stainless steel (SST/Viper)
Remember the goal is to get the RPM at WOT, with the boat trimmed out for maximum speed, within the optimal range for any given motor. For the E-TEC 90 that is 5000-5200 RPM.
|
| |
|
|
| simontonmc |
Posted on 10/24/11 - 12:18 PM
|
Member
Personal Page
Posts: 25
Comments:
0
Joined: 08/15/11
|
Fair enough. Your comments seem spot on. I definitely wasn't feeling it pull to port. The boat is out of town but I'll report back after I take it out again. I'll follow your earlier advice on 25-30 degree trim tab placement. I'll request they put the 17" prop back on for the final test. Thanks again.
|
| |
|
|
| simontonmc |
Posted on 11/22/11 - 6:57 PM
|
Member
Personal Page
Posts: 25
Comments:
0
Joined: 08/15/11
|
So I finally picked up my boat and the steering issue was resolved by adjusting the trim as well as tweaking the trim tab further. The OMC 17" aluminum prop was put back on. However, with a single passenger and partial fuel load and no gear at WOT it's only hitting around 4800 RPMs trimmed out about as far as I could go. Should I be concerned? I'm still trying to get the depth finder set up and I don't have a speedo so not sure how fast it's going.
|
| |
|
|
| Gamalot |
Posted on 11/22/11 - 8:11 PM
|
Member
Personal Page
Posts: 1086
Comments:
3
Joined: 06/21/10
|
Keep in mind that all things are relative in a small boat. You have perfect info above regarding what should work best but you must keep in mind that any change in weight forward or aft will have a great effect. You could move a battery or full gas tank forward by yourself and achieve optimum speed and rpms and then ad another passenger and all bets are off. The smaller the hull the more weight distribution plays an enormous effect. When dialing it in for optimum performance be sure to begin with the same set of circumstances just so you have repeatable accuracy. 60, 80 or 200 pounds in the wrong place could make a huge difference. Those above know their stuff but they don't know your boat and how you have it loaded. 10 pounds up in the anchor locker could easily be the equivalent of 30 pounds back at the console or more fully aft.
|
| |
|
|
| Tom W Clark |
Posted on 11/22/11 - 8:50 PM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
4800 RPM at WOT with a 17" pitch BRP aluminum prop is TERRIBLE. Something is wrong. It might be the boat, it might be the motor, it might be the measurements.
I will reserve jumping to any conclusions but two things remain outstanding (I use that word in the traditional sense) in terms of seeing what is going on:
- We have not yet seen any photographs of the boat in its entirety.
- We have no speed data to go with the RPM data. A depthsounder is not a good source of speed data. A GPS is. Without the speed data, I am very reluctant to draw *any* conclusions.
|
| |
|
|
| simontonmc |
Posted on 11/23/11 - 4:50 AM
|
Member
Personal Page
Posts: 25
Comments:
0
Joined: 08/15/11
|
I'll get my hands on a GPS to get speed. What would be helpful to see in pictures? Happy to do what I need to get it set up properly.
|
| |
|
|
| Tom W Clark |
Posted on 11/23/11 - 7:32 AM
|
Member
Personal Page
Posts: 4280
Comments:
7
Joined: 09/30/05
|
I'd just like to see some photos of the boat, the entire boat, especially one showing it floating. Maybe some shots showing the condition of the bottom. A picture is worth a thousand words.
|
| |
|
|
| simontonmc |
Posted on 10/30/12 - 2:18 PM
|
Member
Personal Page
Posts: 25
Comments:
0
Joined: 08/15/11
|
So following up on an old thread I started last year.
My 1979 17' Montauk w/ 2012 90 E-Tec will still only turn about 4800 RPM with a single passenger and limited cargo. I'm running a 17 aluminum BRP prop and it tops out at around 38 mph on a smooth river w/ no wind and idle tide. Its got a coat of bottom paint and granted the bottom has some imperfections, but I still wonder if I should switch out to a different prop.
|
| |
|
|
| ursaminor |
Posted on 10/31/12 - 1:31 PM
|
Member
Personal Page
Posts: 67
Comments:
0
Joined: 08/12/12
|
I'm running the same engine on a 1989 Montauk 17. The engine is mounted two holes up and I'm running a 13 1/4 x 15 Stiletto Advantage propeller. My boat does have some residual bottom paint left from previous owners. With myself and 12 gallons of fuel, I run 5,200 RPM and 41 MPH. It gets there in a hurry too. Something is not adding up. Even right before it died the original 2 stroke Mercury 90 mounted all the way down would turn 5300 RPM and 39 MPH with an aluminum 19 pitch prop if I trimmed it out. Hope this helps, good luck.
1989 Montauk 17 / 2012 90 HP Evinrude E-TEC |
| |
|
|
| kamie |
Posted on 10/31/12 - 2:15 PM
|
Member
Personal Page
Project Albums
Posts: 2975
Comments:
3
Joined: 11/04/05
|
Is the speed via GPS? Is the 4800 the average of two runs, trimmed all the way out as far as you can? You might have to drop to a 15 pitch prop, but I agree something doesn't add up. When you trim all the way out, where is the cavitation plate, out of the water or under the water? Do you have a photo of the boat with the engine tilted down?
|
| |
|
