1979 Merc 90hp (New Guy with ??'s)

[Fishin4fun]

I have been offered a 79 Merc 90hp that "starts easy, has 142-149lbs compression in each of the 6 cyls. Comes with tilt and trim ss prop and 2 spare alum props. Also comes with extra trim motor. Guy wants $350. 2 Questions, one is, is the price in line? the other is, what should I look out for on this? as far as problems that I might be able to avoid? I know a used motor is exactly that a used motor. Just wondering if there are any other things I should look for before the purchase.<br /><br />Thanks

 

[Hooty]

Re: 1979 Merc 90hp (New Guy with ??'s)

The price is right but if the compression really is 142-149psi, ya better burn avgas in it.<br /><br />c/6<br />Hooty

 

[Clams Canino]

Re: 1979 Merc 90hp (New Guy with ??'s)

Price is great. Make sure max advance is set to 21 degrees and burn at least mid-grade gas. And Hooty that's why I stress 21 and good gas, a lot of them do make 145.<br /><br />-W

 

[LubeDude]

Re: 1979 Merc 90hp (New Guy with ??'s)

Very reasonable price, but you might want to do a decarb just in case its carbon buildup on top of the pistons causing the above average comp readings.

 

[Fishin4fun]

Re: 1979 Merc 90hp (New Guy with ??'s)

I spoke again with the guy. He told me that all that has ever been used is quicksilver mixed with super unleaded. He also said never to use gas over 3 weeks old. Does this sound like a guy that knows how to take care of it, or am I getting a line? Does it really need super unleaded? Will it help keep life long? What about the quicksilver only for mix?<br /><br />Thanks