OMC Quiet Rider

If you go walking thru a boat show today you will see a number of new boats with outboards hidden behind covers. The Searay 370  is one of the best known example of this. With Twin Mercury outboards hidden under fiberglass cowlings forward of the transom, it looks like a sleek express cruiser with a secret.

Of course this idea isn’t new. People have been trying to hide outboards basically since outboards were invented.  You will notice a small addition to the Mercury in the Searay above, a fresh air vent to keep the engine well fed with clean air. I have seen this in a few homemade wooden boats and a handful of modified sailboats thou of course without the nicely molded OEM cowl.
Why you might ask do people want to hide their shiny expensive outboard. Well for one lots of people don’t like the look of them hanging off the rear of the boat. They also tend to handle differently then inboard boats due to both their prop design and extreme aft placement. By moving them forward you can use them better for pivoting while docking etc. They also tend to quiet the outboard down.
Why not just install a stern drive? Several reasons. One for most of the past few decades stern drives used automotive engine blocks as their bases. While this works well in certain marine applications it does not normally perform as well as an engine designed for the specific task (note we now are seeing new marine specific sterndrive engine blocks again). The design also requires some packaging tradeoffs such as the large amount of space forward of the transom and the fact that you have introduced complexity with two ninety degree drive shaft changes as well as a CV joint and transom sealing issues.
On to the title. In 1991 OMC came up with the OMC quiet rider with 90hp, 115hp and 150 hp power heads. While at first the concept looks much like the conventional outboard slapped in a well, OMC actually seems to have spent quite  bit of time and energy developing it. You can tell by the name quiet rider that the main idea was sound proofing. This was based on a 2 stroke V4 OMC (V6 for the 150) power head which, while a very rugged engine, are not the quietest power plants around. To hush things down a fiberglass enclosure was added over the engine but they also sealed the cowl much more tightly now that air was coming thru a ducted hose rather then inlets in the cowl. the result was greatly reduced noise level in the boat. Noise levels behind the boat were similar to the regular out board as the opening rear of the transom was maintained to keep the boat an outboard in the eyes of the USCG etc as well as allowing for exhaust to exit.
The cowl was not only designed to fit better it also was more form fitting to allow for the smallest possible enclosure while still allowing for the motor to fully tilt. The designers also moved the pivot point of the out board lower then normal to accomplish the low cowl height. The motor now pivots on two brackets on either side of the transom notch rather then on the steering tube assembly which is bolted to the transom as with most outboards.
These pivot brackets were bolted into stringers that were located on either side of the transom notch. On the other side of the pivot bracket were two aluminum tubes on which the actual outboard was hung. With the force now directed into the stringers the outboard had a much more secure mounting and the engineers could better isolate the NVH then they could on a boat with a standard transom.

The Quiet rider was never sold to other boat companies outside of the OMC brands. In the early 90’s OMC owned several in house brands. The first brand to introduce the Quiet Rider was Sunbird on their Eurosport line. I believe only a 19′ (190) and later 21′ (210) models wre made. There was also a 19′ Chris craft version (another brand owned by OMC) but I have never seen one in person. I seem to remember seeing a version of a Sunbrid Neptune walk around with a Quiet Rider, but no information on this seems forth coming on the web. In the end the Quiet Rider was cancelled in 1995 due to slow sales and some issues with certain models stalling and running poorly thanks to exhaust build up in the transom notch. Some see this as an OMC deadly sin, I look at it more as a engineering company trying to solve a problem in a unique way.
These boats are still around, in the past 3 years I have seen at least 3 Sunbirds with the Quiet rider system come up for sale here in Connecticut. Pricing is all over the map but must were advertised in the $2,500 range. Hopefully a few will survive as most parts are shared with other motors, but eventually there will be fewer and fewer as corrosion claims the custom aluminum bits that support the motor. Just another chapter in american boating history.


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  4. I need a manual for my sunbird eurosport with OMC 90hp outboard motor. If anyone has one please email me

    1. Wish I had one. I think the parts books are online at Crowley marine if you punch in the engine serial number. Other then that for the power head I imagine alot of the info in the regular V4 service manual should apply.


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