Might buy a used 75 hp this weekend,need advise!!

[wilson750]

The motor is a merc 2000 75hp 2stroke
What is a good number on the compression check?
What number compression is to low to buy?
What more would you check out on the motor? I was going to look over all the wires to check what kind of shape they are in?
How long do you run the motor befor you do a compression check?

Also what is your opinion on this year motor and hp?

Thanks

 

[sutor623]

Re: Might buy a used 75 hp this weekend,need advise!!

Compression should be within 10% of each other. This is more important than the actual numbers. My Merc 65hp runs 125PSI in all four cylinders, Johnson 9.9 runs 110psi in both cylinders, Johnson 4 hp runs 75 in both cylinders. That will give you some idea. Id say if the numbers are within 10% and are 110 or higher you are good to go.
I do a dry test, wet test and warm test when I test compression. Check compression first thing, then add oil and test it again. Numbers shouldn't change much. Then warm up motor for a few minutes and check again. OR, you can scratch all that and buy a leak-down tester, although not sure how much the seller will like you running an air compressor from his power supply.
If you really wanna go all out, you can drain out the L/U oil, and check for metal and water. The best way to check for leaks down there is with a small hand pump leak tester, basically you pump 8-10PSI of air into the L/U and see if it loses pressure over a 10-20 min. time span. I am a meticulous bast*%&, but have yet to get screwed over on a motor

 

[sutor623]

Re: Might buy a used 75 hp this weekend,need advise!!

P.S. I even bring a quart of L/U oil with me, so that I can drain the oil to check it and I will offer to refill the L/U with fresh oil for letting me check it. Typically, if it has metal shavings in it I still buy the motor, for a lot less of a price, because I pretty much call the seller out on trying to sell me a bunk motor. Funny how well motors will run in a bucket as a pose to pushing a boat.

 

[wilson750]

Re: Might buy a used 75 hp this weekend,need advise!!

Thanks sutor,

I think I have many ideas now for the weekend..

 

[wilson750]

Re: Might buy a used 75 hp this weekend,need advise!!

Just got back from the motor..Well it ran great...it had 100 psi on all 3 cold, and was about 110 on all 3 warm..sounds good to me..

I pick it up next week when he pulls it off the boat..The owner said it was a 2000 75 hp.. The tag says 2002 75elpto? Isnt that a 2002? Better for me if that is correct..Got it for $1700 with controls..Sounds like a home run to me!!

 

[sutor623]

Re: Might buy a used 75 hp this weekend,need advise!!

Yeah Wilson, sounds to me like ya done good!