"Checking A Motor Out...Help"

[frustratedboater]

Greetings All:
I will be checking a Merc 250 (I think its low-mid 90's) outboard out for a friend to see whether the boat & motor is a "good buy" or not. I consider myself an okay mechanic, but not sure what to check for other than compression, leakdown, water in the lower unit, and checking if it fires!

I would really appreciate your help on this one. Big motors aren't really my forte. My friend said that the owner stated that the motor hasn't ran in a few years, meaning it has been sitting. What should I check for? Thanks so much,
~FB~

 

[trussmonkey]

Re: "Checking A Motor Out...Help"

take a look at the electrical wires, to make sure their coating is in good condition

any motor that has sit for any period of time will need the basic maintenance (carbs will need cleaned, water pump changed or rebuilt, new oil in lower unit, fuel pump may need rebuilt)

if you are checking compression make sure to inspect the plugs when you pull them

take notes on everything (you may not look cool, but you'll feel stupid later if you don't!)

 

[mikeneal]

Re: "Checking A Motor Out...Help"

I dunno what the acceptable compression range is, but correlation between cylinders is always a good start. Only other thing I would add it remove the bottom gear case oil fill plug and let a small amount of oil come out to inspect the gear oil for water intrusion or anything else ugly.
Can you sea trail it ? If compression is good, oil looks clean and it seems to make right amount of power I say "good to go".

 

[frustratedboater]

Re: "Checking A Motor Out...Help"

Guys,
I really appreciate the advice. Always admire all the guys' input here on iboats! I will take those considerations when I look at it. Thanks,
~FB~