Quick question about a small outboard motor; Paging Dr Curtis.

This old 10 hp Johnson is on a local online auction. No description on condition. I know basically nothing about boat stuff. Are parts still readily available? Any good reason not to throw a fairly cheap bid at it? Thanks

From the logo, thats a 60s model.  I have a 15 or 18HP with that logo from 67?  Been a while since I set eyes on it.

Yes, everything is available. Great motors if not locked up or anything weird.  Contact your local AOMCI chapter with any in-depth questions.

You should be able to find a runner in good condition, with tank, for around $200-250. Or you could 6ish years ago when I was deep into classic outboards

Most of what little I know about outboards is what I learned as the second owner of a 1983 Johnson cross flow 90.  Near as I can tell, the stuff from the 80's and prior is quite robust and generally well supported.   Put me in the "if it isn't locked up, go for it" camp.

If you can get a model and serial number you can get an age.  Based on looks I would guess at 1970s.  Compression is the key issue, it drops as they get older and then they lose power and smoke.  When it gets below 90 it won't start well.  The good news is parts and manuals are still available.  But the manual will cost more than it is worth!

I think they started that font and logo in 1965 or 66.

They are pretty bulletproof.  As long as it has compression, it will likely run on maple syrup.  Whatever OEM parts are NLA, the aftermarket has you covered.  About the only thing that fails on these are the coils, and last I checked they were $18 each.

Change the lower unit oil, plugs, and clean out the carb and it will likely start on the first pull.  I would suggest replacing fuel lines under the cowl just so you don't have to stress about ethanol in fuels.  I run plain pump gas (up to 15% ethanol) in my outboards and no worries.

I have a 10-horse Evinrude from 1958 that still runs.  It has been pull started so many times that the teeth on the flywheel wore to the point where they wouldn't engage anymore.  I ran it long enough that the pinion gear in the lower unit needed to be replaced. I have a 20-horse Johnson from about the same era as the one you posted and it's still getting 3 months of use every year.  I have a 9.9 from 1981 that was part of a rental fleet and was used every day from May to October.

I'd drop a bid of $250 on it and see where it goes.  I wouldn't be surprised if it gets to $400 pretty quick.

If you get it, stick it in a bucket of water and run it.  If it doesn't start "peeing" within 10 seconds, replace the water pump.  If it's been in use recently, it's likely good, but if it sat for any period of time it's probably wasted.

Underneath the cowl they were pretty much the same engine for many years, like Curtis said those OMC outboards (Johnson, Evinrude, Gale and a few others I don't remember) were a pretty bulletproof design.  When I was a kid my dad had a 30hp Johnson and a 5hp Gale, and they just ran and ran.

I recall when they went from 10hp to 9.5 and then 9.9.  Nothing changed about them, but they did it for loophole reasons.  Some states had some lakes where the rules were "less than 10 hp" and other states had rules that said "no more than 10 hp."  Making it 9.5 or 9.9 removed that marketing hurdle.

Also, in the mid-80s, outboards went from being rated at the flywheel to being rated at the prop, so an older 10hp is more like 8hp compared to a modern outboard.  I think OMC tested their newer 9.9 powerheads at 12.8 hp or something in order to get 10 at the propshaft.

Otherwise, those powerheads haven't changed much.  You'll find points and traditional coils under the flywheel, and if you want, you can convert to a later CDI.  It's a better spark, but the CDI boxes weren't as reliable.  They were mounted to the block so they got all the vibes and heat.

I should also add - never run them dry.  You're OK to pull it slowly to check compression, but it doesn't take much friction on the water pump to toast it.  They're not like an automotive water pump which uses impellers in a housing, it's a rubber "gear" looking thing that seals to the side of the housing like pictured below.

Ok, a little more digging.  Johnson only did a 10hp between 1949-1963, then they changed to 9.5 in 64, and 9.9 in 74.

The first year I knew of for that square cowl was 1962, so it is most likely a 62 or 63 model

The model number will tell you.

1961 = QDL-22
1962 = QDL-23
1963 = QDL-24

Unlikely a 61 because the 61s had a funky face on the cowl with the idle mixture like this:

62 or 63 looks like your huckleberry:

I had a 63 Johnson 10, bought new by my great uncle, then given to my grandfather.  Started on one pull almost every time. I used it on rental boats from the Mosquito Lagoon and the St Johns River to Lakes Erie, Ontario and Huron. Awesome motor.