Re: Help buying a 15 HP evinrude
I've got an 86 15Hp Johnson (same as the Evinrude).
What I would do is look the motor over as best as you can. Look at the powerhead and see how clean it is. You can tell fairly quickly how well a motor may have been looked after and treated just by its general appearance condition (but not all the time)
If you have a compression tester, take it with you and test the compression on both engines. You want each cylinder to be within 10% of each other on the compression reading, and ideally each over 100 (but not as critical as having both readings close to each other).
Pull the spark plugs and have a look at them. If they are brand new, you might have cause to suspect problems. Owner may be covering up some ignition issues by using brand new plugs. If not, look for poorly conditioned plugs that are black or crusty. You want fairly clean plugs with a light tan coloration on them (indicates healthy ignition and combustion).
As them to start it up and check for telltale water stream. This doesn't really indicate there is good flow around the motor but will at least let you know the impeller and water uptake is in serviceable condition.
Look for any burning or discoloration on the heads as this could be a sign of overheat damage. If you have an infrared thermometer, check the head temperature while the engine is running.
have them start it up and listen to see if there are any unusual noises and if testing in a tank, give the throttle a little nudge and see how quickly the engine responds to changes in throttle. Check also how smooth the gear change is. Could indicate gear problems if it is very clunky or hard to get into gear.
Look for leaks of anything anywhere!
Thats about all I can tell you.
Most other checks require pulling something off the motor.
