Outboard isn't low enough... Advice on rebuilding mount?

centerline · Nov 16, 2014

from the photos, your only option is to trade that motor in for one with a longer shaft... there is nothing you can do with what you currently have to insure the prop will stay in the water and the motor head will stay out of the water....

if you get out in a bit of slop with your set up as shown, you will quickly see what i mean....
and, 2.5 is a bit under powered is your pushing thru slop (wind chop and waves)....

moving the prop deeper into the water IS what you need to do, and it WONT interfere with the rudder... but only if you move it over to the side a bit farthwr that what you have it now.
the motor does not have to be and should not be on centerline with the rudder... its a bad idea to have them so close so that they could interfere with each other.

if you are determined to try and use that motor, unbolt the motor bracket from the transom and move it down.... drill new holes then bolt it back on in the new locartion. plug the old holes with bolts...
then when you decide you actually do need the longer shaft motor, you can just move it back up to where it is now

Seahorse24 · Nov 16, 2014

Hooks said:
So I tried to take the boat out today and learned that the motor is not going deep enough in the water to safely operate it. I don't want to hit waves and it pop out the water and suck in air. Any advice on rebuilding the mount where the motor can go down another 9-12"? Do you think it would interfere with the rudder if it were lower? Pics attached.

It's a 2.5 HP motor and I know I probably want something bigger but still paying off the boat and don't know if I really want to upgrade the motor. This is my entry into sailing and I want to spend as little as possible on it as I plan on moving to something bigger once I get comfortable with sailing and living aboard.

You can lower the motor by adding two pieces of aluminum angle. Measure the distance you want to lower the motor. Then cut the two extensions to a length that extends from the top of the angle mounts currently attached to the stern to a point that allows you to reconnect the extension arm low enough that the prop and water intake stay below the surface. The top part of the angle will attach using the existing holes where the two existing Are currently bolted to the stern. The swing arm that extends out toward the motor will then attach the the bottom portion of the two new extension pieces. You can make this in less than an hour. You can get the 1/8 inch thickness right angle aluminum piece at Lowes in a 3 foot lengh. If you need specifics on how this should be done, I can draw it out for you and post the drawing. Your cost will be less than twenty dollars. Let me know if you want me to draw it out.

Seahorse24 · Nov 16, 2014

Hooks said:
I would love if you could draw it out. My uncle is good with this kind of stuff and if he had a picture to work with we could get it set up Sunday.

I edited my previous post. Did my quick drawing clarify how it is done? If not I'll have another go at a better drawing.

Seahorse24 · Nov 16, 2014

Hooks said:
It might make sense to him but I'm a little confused Sorry

Not a problem. I'll draw it out better and post a better drawing with a detailed explanation. It might take me a hour or so.

centerline · Nov 16, 2014

Seahorse24 said:
You can lower the motor by adding two pieces of aluminum angle. Measure the distance you want to lower the motor. Then cut the two extensions to a length that extends from the top of the angle mounts currently attached to the stern to a point that allows you to reconnect the extension arm low enough that the prop and water intake stay below the surface. The top part of the angle will attach using the existing holes where the two existing Are currently bolted to the stern. The swing arm that extends out toward the motor will then attach the the bottom portion of the two new extension pieces. You can make this in less than an hour. You can get the 1/8 inch thickness right angle aluminum piece at Lowes in a 3 foot lengh. If you need specifics on how this should be done, I can draw it out for you and post the drawing. Your cost will be less than twenty dollars. Let me know if you want me to draw it out.

it would probably never be an issue with a 2.5 hp motor, but in reverse or a surging sea, ALL the stress is going to be pulling outward on the 2 lower bolts.

the angle extensions cause the stress loads to multply... just something to be aware of.

Seahorse24 · Nov 16, 2014

Seahorse24 said:
Not a problem. I'll draw it out better and post a better drawing with a detailed explanation. It might take me a hour or so.

How to lower the motor.

You are going to replace the two short metal brackets that are bolted to the stern with two longer pieces of right angle aluminum 1/8 inch thick. Probably 1 and 1/2 by 1 and 1/2. You can use 2 inch by 2 inch if you prefer.

Use the two existing metal brackets you remove as the pattern for the holes that will be drilled in the two new Aluminum pieces. The difference will be that the holes where the swing arm will be located will be lower down on the new brackets.

You will need to determine how many inches you need to lower the motor. The new brackets will be that much longer than the existing stern brackets. The water intake on the motor must remain under water whenever the motor is running. 15 seconds of dry run time on the lower unit water pump can damage the rubber water pump in the lower unit.

Seahorse24 · Nov 16, 2014

Seahorse24 said:
How to lower the motor.

You are going to replace the two short metal brackets that are bolted to the stern with two longer pieces of right angle aluminum 1/8 inch thick. Probably 1 and 1/2 by 1 and 1/2. You can use 2 inch by 2 inch if you prefer.

Use the two existing metal brackets you remove as the pattern for the holes that will be drilled in the two new Aluminum pieces. The difference will be that the holes where the swing arm will be located will be lower down on the new brackets.

You will need to determine how many inches you need to lower the motor. The new brackets will be that much longer than the existing stern brackets. The water intake on the motor must remain under water whenever the motor is running. 15 seconds of dry run time on the lower unit water pump can damage the rubber water pump in the lower unit.

Here is one additional photo that may help clarify.

Seahorse24 · Nov 16, 2014

centerline said:
it would probably never be an issue with a 2.5 hp motor, but in reverse or a surging sea, ALL the stress is going to be pulling outward on the 2 lower bolts.

the angle extensions cause the stress loads to multply... just something to be aware of.

Certainly something to think about.

The moment arm ( additional stress ) may be four or so inches longer. Since the motor is only 2.5 horsepower the angled aluminum should be plenty strong enough to handle the load. The bolts going through the stern appear to be large enough to handle the additional moment arm of the extended brackets. Worst case would be going with larger nuts and bolts through the stern and thicker Aluminum, but I doubt that will necessary.

Seahorse24 · Nov 16, 2014

Seahorse24 said:
Certainly something to think about.

The moment arm ( additional stress ) may be four or so inches longer. Since the motor is only 2.5 horsepower the angled aluminum should be plenty strong enough to handle the load. The bolts going through the stern appear to be large enough to handle the additional moment arm of the extended brackets. Worst case would be going with larger nuts and bolts through the stern and thicker Aluminum, but I doubt that will necessary.

You could use steel angle and paint it with galvanizing spray paint. Steel is cheaper than aluminum and much stronger. My son and I have used steel painted with galvanizing paint on dock standoffs. They last twenty years under water. You have to get the steel clean before painting it. All surface area has to be covered with the paint. Just another idea to consider if you have scrap steel angle laying around.

Charlie Jones s/v Tehani · Nov 16, 2014

Yamaha (and most other engine makers) has extension kits available to change from short to longer shaft, I.E from 15 to 20 inch. Whether they have one for that engine I couldn't say, but sure worth a check before you screw around with the mount.

Ted · Nov 16, 2014

Advice on rebuilding mount

You've got two other problems to consider if you lower the engine.

1. It will be difficult to reach the gear shift and throttle controls after you lower the engine.
2. The engine will be susceptible to being swamped with a following sea.

If you're concerned about safety, your best solution is to sell the existing motor and get a long or extra long shaft one.

31seahorse · Nov 17, 2014

The long or extra long shaft motor is the best solution, but choosing weather conditions carefully the bracket solution drawn and described by Seahorse24 would get you into the water quicker. If you choose that solution be sure to add backer plates inside the transom before you put on the nuts. I would bet that there are none or small washers there now. Also, carefully caulk the area where the bolts go through the transom.

Depending on your launch area configuration, amount of activity there, and taking an experienced sailor with you, you might try just sailing without changing the bracket at all. Sitting in the stern and adjusting the position of other crew on the motor side should lower the motor a bit for the necessity of motoring out from and back to the dock. Many people day-sail without a motor.

In addition, that motor bracket has already had some modifications performed on it. The part where the motor attaches was changed. You might be able to modify that area with angle, channel, or rectangular tubing to move the motor back and down to accomplish what you need. moving the motor back from the bracket with those pieces of 2 X 2 is what was done earlier. Other types of motor mounts called high-low mounts are also available. Check ebay, any local used marine parts places, or the SBO store for options.

davidmhull · Nov 17, 2014

You might try and replacing your motor mount and just move it down temporarily. When you get a long shaft motor you can fill the holes and move it back up without too many problems. You might just make it extra long and move the Garlick down a few notches for now and use another set of holes to move it up when you get the long shaft. That way you don't have to drill new holes and remount you wedge. I don't know if this will work but I tried putting in a link to a thread I started about making a new wedge. It worked out really well so far.

http://forums.oday.sailboatowners.com/showthread.php?t=167096

Benny17441 · Nov 17, 2014

In my opinion it would be a mistake to relocate or modify the motor mount to latter find out that a 2.5HP is grossly inadequate to power a 24' boat. The base probably originally installed for a larger motor seems to have been already modified by adding wooden spacers and lowering the base to allow clearance for the engine attachment and to try and lower it. The resulting adjustments are inadequate. It may not be in the budget but I would recommend you start anew by installing a new motor mount with a vertical travel of at least 11" and installing a long shaft engine with 6-8HP. As is you will not enjoy the boat and safety will be compromised in less than an expert sailor's hands.

Outboard isn't low enough... Advice on rebuilding mount?

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