Reply
 
Thread Tools Search this Thread
 
Old 06 August 2017, 04:23   #1
Member
 
Country: UK - England
Town: poole
Make: flatacraft
Length: 5m +
Engine: 55hp yamaha
Join Date: Sep 2014
Posts: 23
very hard steering after outboard change

Hi
I have a flatacraft 5m rib, it originally had a yamaha 55 which was great, nothing wrong with it and the steering was really light, one hand operation was easy.
I was offered an evinryde etec 75 at a bargain price so obviously snapped it up. sold the yamaha and stuck the evinrude etec on the back with new steering controls.
I love it, but!

When the boat is stationary the steering is light and smooth.
Under power it is really heavy to turn with 2 hands! impossible with 1!

unfortunately, i didnt take note of the height of the previous motor....

i will try to add a photo to show height in relation to hull...

Im not sure what the prop is, its just a standard aluminium one that has quite a lot of paint on and cant see the numbers.

the trim tab is missing from the underside of the anti cav plate but i dont think this would make the steering heavy....the boat holds a reasonably straight line without it but i will get one.

At about 35mph, i am trying to trim out(up) to get the bow up but before it does the prop starts to leave the water and the revs go sky high.
It seems the hull is really digging in.

Click image for larger version

Name:	leveled with hull line.jpg
Views:	179
Size:	135.6 KB
ID:	121255

Click image for larger version

Name:	2017-06-17 11.23.07.jpg
Views:	154
Size:	152.9 KB
ID:	121256

Could the motor be too high?
what prop would benefit me?
any ideas welcome?

smee
__________________

__________________
smee is offline   Reply With Quote
Old 06 August 2017, 06:16   #2
Member
 
Country: UK - England
Town: penzance
Boat name: not named
Make: ski boat
Length: 5m +
Engine: 150 HPDI
Join Date: Sep 2013
Posts: 122
Get a tab - you'll be surprised how much torque it'll cancel out.

There's only so much lift at the nose you can get from an outboard, and you're sat up front. Are you sure you're not just trimming it out of the water? How does the wake look?
__________________

__________________
simonl is offline   Reply With Quote
Old 06 August 2017, 07:13   #3
Member
 
Country: UK - England
Town: poole
Make: flatacraft
Length: 5m +
Engine: 55hp yamaha
Join Date: Sep 2014
Posts: 23
I have not been able to get to the back of the boat whilst under power to look at the position of the anti cav plate but i have a feeling the prop is leaving the water.

ive only been out with the wife a couple of times and too scared to let her drive while im looking over the back!!!

i thought that the outboard mounting height looked pretty good judging by other forums/internet/pics but i am tempted to try dropping it down a couple of holes. It seems the most popular position is to have acp a couple of inches above the bottom of the hull, which i have.

The old outboard was mounted quite a bit lower but i cant remember what length the leg was and where the anti cav was positioned.

I really should take it out again and check out the height whist running before i do anything.
__________________
smee is offline   Reply With Quote
Old 06 August 2017, 09:12   #4
Member
 
Country: Ireland
Town: Castlebar
Boat name: Clewless
Make: Valiant DR 490
Length: 4m +
Engine: 60 hp ETEC
MMSI: Awaitng one
Join Date: Oct 2007
Posts: 1,213
RIBase
Is part of the skeg broken?
__________________
two stroke mick is online now   Reply With Quote
Old 06 August 2017, 10:34   #5
Member
 
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 675
I was wondering that too.
Looking at other pics online it does look like something's going on with the skeg & possibly a substantial amount of it is missing.

Might also be a bit high. Put a straight stick along the keel & see where it is in relation to the plate.
The Outboard Expert: Boost Speed with Outboard Engine Height Adjustments - boats.com

Basics for prop selection involve the boat normally loaded & runs at WOT.
Record the WOT revs achieved & see if that figure falls within the parameters specified by Evinrude.
BUT I'd suggest you get the height & skeg sorted before.
Clean the prop up & see what you've got.
__________________
paintman is offline   Reply With Quote
Old 06 August 2017, 10:41   #6
Member
 
Country: UK - England
Town: surrey
Length: 7m +
Join Date: Apr 2012
Posts: 319
get the trim tab as above, that will almost definitely be the main part of the problem and yes a big chunk of your skeg is missing! (should look more like this) Also i would say your engine needs lowering by 1 or 2 bolt holes (ish)
Attached Thumbnails
Click image for larger version

Name:	E-Tec90-01.jpg
Views:	81
Size:	78.9 KB
ID:	121259  
__________________
wellhouse is offline   Reply With Quote
Old 06 August 2017, 11:06   #7
Member
 
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 675
Didn't put this in my post above, but if there is a big chunk of skeg missing then this will also affect the steering & may well be a part of your problem.
__________________
paintman is offline   Reply With Quote
Old 06 August 2017, 15:12   #8
Member
 
Country: UK - England
Town: penzance
Boat name: not named
Make: ski boat
Length: 5m +
Engine: 150 HPDI
Join Date: Sep 2013
Posts: 122
Quote:
Originally Posted by paintman View Post
Didn't put this in my post above, but if there is a big chunk of skeg missing then this will also affect the steering & may well be a part of your problem.
I can't see why that would affect the steering torque, unless it's bent - does it look straight from behind? If bent I would just correct with the tab.
__________________
simonl is offline   Reply With Quote
Old 06 August 2017, 15:23   #9
Member
 
Country: UK - England
Town: poole
Make: flatacraft
Length: 5m +
Engine: 55hp yamaha
Join Date: Sep 2014
Posts: 23
yes a bit of the skeg is missing....not guilty!

looking at paintmans link, i can see i must be a good 2 inches above the motor shown.

when i get time i think i will drop it down at least two holes. looks like the simplest thing to do.

if i can get it to handle as it did with the old motor i dont mind if it goes a couple of mph less....
__________________
smee is offline   Reply With Quote
Old 06 August 2017, 16:26   #10
Member
 
neil.mccrirrick's Avatar
 
Country: UK - England
Town: Oldham
Boat name: Nemanda
Make: Aluminium
Length: 6m +
Engine: 140hp Tohatsu
MMSI: 235065639
Join Date: Jan 2008
Posts: 860
Most of your skeg is missing while this protects the prop it will also direct water and ease the steering. Try these guys for a cheaper repair option http://www.gmtmarine.co.uk/index.php...skegguard.html
__________________

__________________
If you don't like my opinion, I have others.
neil.mccrirrick is offline   Reply With Quote
Reply

Tags
outboard

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 06:08.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.