Do you have a heavy four-stroke outboard motor on your sailboat? Is it a chore to raise and lower with your current motor mount? Maybe you have a back injury that makes lifting a risky behavior. What about your first mate, can they raise and lower the motor if they need to? All these are good reasons to consider whether your current motor mount is adequate for your needs.
Before I get started, a bit of legal housekeeping. This post contains affiliate links. That means I receive a small commission if you make a purchase using these links. You can purchase the products anywhere you like, of course. For a complete explanation of why I’m telling you this and how you can support this blog without paying more, please read my full disclosure.
Summer Dance has a 2004 Yamaha 8 HP long shaft outboard motor (model F8MLHC) that weighs 87 pounds. When we bought her, the outboard was mounted on the original equipment Garhauer-made two-spring motor mount. (Incidentally, this motor does a great job of charging a deep cycle battery when you add a rectifier/regulator to it.)
My achy breaky back
The Garhauer mount is rated for up to 80 pounds but I think the springs have lost some of their strength over the years. Before I replaced it, hoisting the motor up out of the water wasn’t an easy task – there was way more than the 7 pound difference between the motor weight and the mount rating. Other than that, it’s a good mount and has held up well over 34 years.
It wouldn’t be so bad if the motor were closer to the top of the sternrail but in its lowered position, I had to lean way over the sternrail to grab the mount handle and hoist the motor up. With apology to Billy Ray Cyrus, I don’t recommend it if you have herniated disks and a broken vertebra like me. It was becoming such a chore that I started looking for a way to spend more time enjoying sailing and less time nursing my back.
The way these mounts are built, it’s impossible to simply add more springs to them. That would have been my first choice for a solution but the tubes that the springs are assembled on are welded together. Except for cutting and re-welding them, there’s no way to add more springs.
OMC, gone but not forgotten
Rather than replace the mount with a different model with more springs, I decided to look for an alternative design. I remembered reading on the Chip Ahoy blog how Chip added the missing gas spring to his OMC Auxiliary Motor Bracket. OMC is no longer in business and the motor bracket is no longer in production, but used ones appear regularly on eBay. It looked like a solid design and easier to use, so I started watching for a bargain. By the way, the corporate history of OMC is an interesting story in itself.
The OMC design is similar to that of most other outboard motor mounts, control arms in a sliding parallelogram arrangement that keeps the outboard motor vertical as it is raised and lowered. It works on the same principle as the front suspensions of most cars. But it’s also different from other mounts in several ways.
First, instead of stainless steel, the major parts are made of plate and cast aluminum painted white. Second, instead of a large handle that actuates the latching mechanism, there’s a small, spring-actuating lever. And last but most importantly, instead of multiple coil springs to compensate for the motor weight, it has a single gas spring. Gas springs provide more consistent force throughout their range of motion than coil springs.
To use the OMC mount, you just flip the lever to the opposite of its current position to disengage the latch. This transfers most of the weight of the motor to the gas spring so that you can easily push or pull the motor into position until the latch re-engages. A video at the end of this post shows how.
When a used OMC mount appeared on eBay at a really low price, I bought it almost immediately. It arrived in very good condition and looked like it had been used relatively little.
First, I disassembled the mount, refinished the oak board, cleaned all the parts (Mr. Clean Magic Eraser Cleaning Pads work great on oxidized paint and stubborn stains), polished the hardware (I like Flitz), and replaced half of the Nylon bushings on which the parts rotate.
If you decide to refurbish one, don’t try to buy the OEM bushings (part numbers 25 and 27 in the diagram below) from a marine parts retailer. Part #25 is no longer available and for #27, marine retailers are asking $9-$10 EACH!
Instead, order standard 5/16″ ID flanged clip Polymer bearings (part G0242636) from an industrial supply company like Zoro.com for $1.95 per pack of 5. They will replace parts #27 (4 required). If you want to also replace the bushings at part #15 (2 required) or #25 (2 required), consider standard 3/8″ ID flanged clip Polymer bearings (part G0270837, $2.52 per pack of 5).
Transom mounting tricks
With the OMC mount reassembled, it was ready to replace the old Garhauer mount. Unfortunately, the OMC mount doesn’t have the same bolt pattern as the Garhauer mount, 6″ x 7″. The OMC mounting bolts are spaced on a 5-1/2″ x 7″ pattern. I resolved the difference by elongating the bracket holes horizontally by 1/4″ each.
The Garhauer mount on Summer Dance used six bolts through the transom because the previous owner wanted to raise the motor for some reason. Most C-22s only use four like the OMC mount. I’m not concerned about it being weak, though, because of the aluminum angle brackets that I installed on the inside of the transom to reinforce it for trailering with the outboard motor mounted. (The picture below is of the brackets installed with the old motor mount.)
After the bracket hole modification, I reused the old mounting fasteners and the angle brackets to install the OMC mount in the existing holes in the transom.
How’s it work? See for yourself in this video.
Here are a few other points to keep in mind with this mount.
The OMC mount has less vertical travel than the Garhauer mount so be sure your outboard motor will sit low enough in the water to prevent cavitation. If not, you might have to drill new holes in the transom to attach it lower than your old mount.
Without the outboard motor attached, the OMC mount rattles a bit in the raised position, not due to worn parts but by design. The latch rod and the slot through which it travels are not a close fit on purpose. The raised position is also where the gas cylinder does not apply any pressure. To prevent the rattling while trailering, put the mount in its lowered position to apply pressure from the gas cylinder. If you trailer like I do with your outboard mounted, the weight of the motor prevents rattling.
The Bottom Line
Suggested price: $353.95
$tingy Sailor cost: $53.68