Motor height and how to lift them.

[nowornever1972]

I suspect my motors are to high, as water is channeling up......... I am wondering how to tell what height to run them at and how to lift them up.........there is two holes I can slide the motors up onto.

Id rather do it myself, boats cost me enough as it is lol

[Chimo]

Easy enough to do but you probably should run the boat at med to high speed on the plane and have a good look at the cav plate before doing it, then you will know how much to lift them if they need lifting; which they may well do.

You can use a block and tackle or engine hoist off a beam or lower the motors until their vertical place blocks of wood under them and use the trailer jockey wheel to move the transom. You dont want to do this on your own as the motors will be unbolted for a time as you lift the bow to lower the back to reposition the transom holes so the motor ends up higher when you re attach.

Cheers
Chimo

PS this and your other threads belong in the boating section .................:-[

[Jarrah Jack]

What rpm are you getting at full throttle? Take a pic of the cav plate at cruise speed and post it up if you want. I'll be doing the same with mine as I suspect my motor's too low but its interesting to read what others think.

[WalrusLike]

Chimo I think he meant to lower his motor not raise it... But your method works either way.

Jack I am getting mine raised one hole tomorrow because my cav plate is about 2 inches below water when on the plane. I will see how it goes then.

If it is raised too high it will cavitate badly on turns I think.

[Chimo]

Hi walrusLike

Your correct but he meant to say lift his motor based on earlier discussions

Cheers
Chimo

[Smithy]

Just do it and so long as you have no massive cavitation at full in trim or so you can get a bit of trim on your trim gauge before cavitation. Each gauge is different but somewhere about half way or so on the guage should be where you notice a bit of prop slip. If you get too much, drop it back down a hole.

[marto78]

I have adjusted the height on my motor a couple of times when trying new props and what not. It is a fairly easy job to undertake, I have a 90etec and it is just a matter of removing the top bolts that lock into the holes and loosening off the bottom bolts, this gives the motor enough play to move up and down without falling off the transom. I used a bottle jack with a length of timber up under the mounting bracket and also wound the jockey wheel up or down to help get the right height. You may have to rock the motor a bit to realign the top bolts but that shouldn't be a problem seeing as you only have 70's? on the back.

[raffles]

Both evinrude and mercury recommend your cav plate should be level with the water or a tad above,as long as there is water splashing onto the plate, at normal operating speed. I've just put an early etec 90 on my boat and had it too low to start with. I lifted the motor two holes and it made a world of difference. All the best . Raffles.

[fat-buoy]

There are a lot of people on this site with heaps more knowledge than me but as I just did this job a few weeks back I will put my 2 cents worth in. ;)

As stated earlier the motor has the top holes which are the round bolt holes.. the bottome holes are elongated about 2" - 3" long so essentially the process is this..

Put a chock of wood under the skeg of your motor so that when the dolly wheel is at around half way the skeg of the motor is sitting on the wood.. undo the top bolt and remove ... loosen off the bottom bolts either side of the motor so that the bolt can move in the slot but without the motor swinging in the wind. (you will probably have to cut away the silastic around the bottom bolt to free up the slot area)

Either crank the dolly wheel up or down until the motor is at the desired height.. slip the top bolts into place in the new holes with some nice fresh silastic around to seal off the transom ... tighten the top nuts... put some silastic sealant around the bottom bolts to seal off the transom and then tighten these nuts also.. ease the weight off the skeg of the motor and you are done.

Job takes about 30 minutes including getting the old silastic out of the way..

If the motor has been badly aligned from the start the bottom holes may be outside the range of the slotted area of the motor... if that is the case you are on your own lol... unfortunately you may need some more holes drilled in the transom and you will need either a couple of strong guys to hold the motor or a sling of some kind etc as the bottom bolts will need to be removed also.

As a general rule the cav plate will be around 1" - 2" above the bottom line of the keel so that on the plane the plate sits pretty much on top of the water... I lifted my motor 2" as it felt too low when it was dead in line with the keel and I got an extra 5 kph and 500 rpm with better performance for doing so.. makes a surprising difference.

Hope that helps you out a bit :)

[fishfeeder]

Just make sure you try it in average conditions after lifting the motors.... You might find the Propellers will brake traction and the motor will rev up but you go no where to you back right off and go again... its a huge pain in the ass and could be dangerous if on a bar crossing when you lose forward momentum !!

My motor height looks perfect but I added Trim tabs and now its to high when the tabs are used in rougher then good conditions... I am going to try and get a new prop first before dropping the motor down one hole..

Cheers