Johnson 28 hp

[nordy]

Hello,<br /><br />there is a motor with 20,9 kW (28 hp) out of 737 ccm displacement.<br />What kind of engine is this?<br />Is it a 3 cylinder?<br />I've never seen it in brochures.<br /><br />Nordy

 

[Toyman991]

Re: Johnson 28 hp

Nordy,<br /><br />Johnson produced at least two series of motors rated at 28hp. One of which I own (a 1962 RX-10) that was made, I believe, from 1962-64. These were 2-cylinders that were relatively heavy at 120 lbs. but very well built as they shared many parts with their 33 and 40 hp stable mates.<br /><br />OMC also produced a line of 28hp motors in the '80s known as the 28 SPL. I assume that these were 2-cylinders as well but I'm not sure.<br /><br />Although collectors seem to shun the early 28hp motors, they can provide many years of service if you are willing to overlook their unattractiveness and portly dimensions. <br /><br />John

 

[Paul Moir]

Re: Johnson 28 hp

Nordy - That must be a 28 SPL, made between '86 and '89. The early '60s engines displace 585 CCs.<br />The 28 SPL is a two cylinder model. The bore is 3" (76.2mm) and the stroke is 3-3/16". (81mm)<br />Toyman991 - Don't you be calling my 28hp fat&ugly!

 

[heyttown]

Re: Johnson 28 hp

I Have a 28 hp, but its a 95.......I see people saying that it was in the late 80,s but wanted to clarify that they were built in the 90,s also........It is a 2 stroke.

 

[Toyman991]

Re: Johnson 28 hp

Hey Paul, <br /><br />I didn't mean to slight your motor but you gotta agree that they aren't real lookers. BTW, I love mine. People are shocked when I tell them its age and even more shocked to learn that it's just a 28 since it's about the size on a modern 85hp!<br /><br />Anyway, has yours proven to be reliable? Do you run the full 24:1 mix? There was a runner on eBay last week that had no takers with a starting bid of $105 . If it were within driving distance for me, I'd now own two of them.<br /><br />What do you run yours on? My 1962 RX-10 is on a 1957 Cadillac Daytona 14' and pushes it up to 29 mph.<br /><br />John

 

[Paul Moir]

Re: Johnson 28 hp

Toprunner - Mine spent a week at the bottom of a saltwater inlet in the early 80s - it's been a complete teardown and rebuild since I got it in the early 00s. Actually, I can't really attest to how it runs now, since it's not even broken in yet. Lately, I haven't been running it since it's apart getting prepped for a new paint job, and some other little details. I'm sorta thinking about putting a thermostat on it, and mabey redirecting the cooling water down the exhaust part of the leg to protect the new paint job. You know how it gets burnt on the right side just below the powerhead...<br /><br />Mine's mostly a RX-10. Rods, wristpins and "this and that" comes from a RX-11. Bearings are all new and crankshaft had to be reground (the RX-11 crankshaft had badly corroded splines). Meraculously, the bores on the RX-10 block were in perfect condition! Don't let your engine sink in salt! <br /><br />I'll hopefully be getting to building a wooden runabout for it this spring... My plans are a modified racing runabout, and it ought to go faster than 30 (not much though). I'll post those on the Backyard Boatbuilding soon to get some reactions...<br /><br />I think I'll go 32:1 after the breakin - it's roller bearings throughout. I don't see why it couldn't run 50:1, but I don't want to have to rebuilt it again...<br /><br />PS - If anyone thinks I'm nuts, please understand the original motor has great sentimental value. I had a lot of fun with it as a kid. Too bad the boat's gone...<br />Actually, this project has gotten a little out of control.