buying a used motor

[bigk]

I am looking at a 1988 Mariner 40 hp. The engine looks very clean. I can't see any obvious problems with the motor. I asked the guy at the shop to do a compression test on the motor and he said both cylinders were 140 psi. Is that good? The only thing that concernes me a little is the motor is at a consignment lot and it has a prop on it that has just been redone. Although I can't see any problems or neglect with the lower unit, why would a guy spend the money to have the prop redone and then turn around and sell the boat? Do you think I am worring about nothing or is this a red flag? What else do I need to look at on this motor? The cost of the motor is $1200 and $300 to have it installed on my boat. Is that reasonable?

 

[WillyBWright]

Re: buying a used motor

That sounds a bit steep for a twin. I suppose it all depends on condition. Average condition I'd say that's too much. Excellent condition and I suppose it's fair.

The prop may have been damaged, or the owner may have had two props and put the best one on. Many boatowners have two. Have a look at the gearlube and make sure the propshaft is straight. For that price, I'd expect a fresh water pump to be included (installed and tested). Compression sounds good. Smell the carb. If it smells like gas, it may be okay. If it stinks, then it may need a rebuild. Make sure you get a test run before you pay the full price. Half now, half when it's up and running good. The installation you'll have to deal with separately.

 

[Silvertip]

Re: buying a used motor

"Telling" you compression is 140 may not mean it really is. When you see the readings with your own eyes, then and only then is compression 140. If this is a dealer, they should be able to run the engine in a tank for you. If they are unwilling to do that, walk away or make sure as Willy says, have it in writing that you get a test run and any needed repairs are taken care of. You wouldn't buy a car without a test drive (would you??) so why would you even think about buying a motor you haven't heard run.