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Considering buying a 1971 Evinrude 25hp from Craigslist, how to test?

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Swarlos

Regular Contributor
As title says, I'm considering buying a 1971 Evinrude 25hp outboard from Craigslist. The post says "Runs good". I'm assuming the only testing I can do on the motor before buying it will be on ear muffs. What are the limitations of ear muffs? Should I avoid putting it in gear? How much throttle is safe to use on ear muffs? It being a nearly 50 year old engine makes me nervous, but the price is intriguing.
 
Difficult to run one of those on muffs.-------Run it in a barrel or garbage can.----An excellent motor when it left the factory.----Parts are easy to find in my opinion.
 
Swarlos said:
As title says, I'm considering buying a 1971 Evinrude 25hp outboard from Craigslist. The post says "Runs good". I'm assuming the only testing I can do on the motor before buying it will be on ear muffs. What are the limitations of ear muffs? Should I avoid putting it in gear? How much throttle is safe to use on ear muffs? It being a nearly 50 year old engine makes me nervous, but the price is intriguing.
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A compression test would tell you a lot. You can get a compression tester from autozone/orielly's for 30-40 dollars. If it's a pull start, pull the plugs out, and make sure the plug wires are folded out of the way, so you don't accidentally ignite gas fumes coming out of cylinders, If it has a kill switch, have that engaged too. Do several (5-8) brisk pulls. You should see atleast 100 psi, and make sure there is no more than 10% difference betwwen the readings for each cylinder (10 psi). An exceptional motor will read 120-130 psi, average is around 110-115 psi, good/acceptable readings are 100 psi. However, be careful that the screw in adaptor on the compression gauge that you thread into the spark plug hole doesn't stick in so far that it hits your piston, I had this happen once, and had to shorten the adapter slightly. The pistons come very close to the plug hole opening at top of stroke. If it's electric start, do the same, only run the starter maybe 3 seconds, and check it. Make sure it shifts in and out of gear by putting it in neutral, the prop you should be able to turn by hand both directions freely. Put in forward gear, it shouldn't turn either direction, same with reverse, except a little play both ways. No need to have it running for this. Be careful with muffs, sometimes they don't seal good, you should see water coming out of "pee hole" within 2-3 seconds of initial start, if not, shut off immediately, and readjust the muffs, or better yet, run it in a large barrel of some sort, just make sure the water level is high enough in barrel. There are a myriad of diagnostic tests, to address many issues, but this is a bare minimum before I buy a motor. If i'm satisfied after doing these tests, most other tests i'll do after a purchase to address fine tuning, and optimizing performance/reliability.
 
I have about a 30 gallon plastic trash can I could run it in, but I don't know how well it would hold up when running the motor. I ran a 3hp motor (no neutral gear) in it a few weeks ago and I was afraid running that at full speed would damage it.
 
Swarlos said:
Ok, is there any danger in running it WOT in neutral in a can after it has had some time to warm up?
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All the bits inside that normally whizz round or go back and forth will probably escape. Dont stand too close!
 
I am wary of any online shopping. An unpleasant incident happened to my friend. My friend's father loves to fish. So a friend ordered a boat on Craigslist as a birthday present for his father.​
 
His dad liked the gift. It seems that at first there were no problems with the boat. Then the issues with the motor began. In general, the repair of this boat was more expensive than the boat itself. And my friend decided to look for a Craigslist alternative so that there would be no such situations. It is these cases that make me worry about shopping online. The main thing is always to check what and where you order. In the end, you spend your money on it.
 
Swarlos said:
Ok, is there any danger in running it WOT in neutral in a can after it has had some time to warm up?
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Yes, But on the plus side you probably wont need to disassemble the motor to see inside of it. Ask him if you can put it on your boat and run it on the lake. The main problem with those will be the lower unit.
 
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