FAO: Clams/Laddies Compression

[MercFan]

Hi guys!<br /><br />Can you give me the compression for my '70 1150 when new and minimum?<br /><br />Thanx!

 

[WillyBWright]

Re: FAO: Clams/Laddies Compression

If any have less than 100psi, find out why. If they vary by more than 15psi, find out why.<br /><br />New motor readings are meaningless. It has to be broken in before the rings will seal correctly. For that reason, never pay much atttention to how close they are to each other on a new motor. They'll vary a bunch until the motor is broke in. Expect yours to be below new as a function of age alone.

 

[Laddies]

Re: FAO: Clams/Laddies Compression

Although Mercury does not give any compression numbers in their manuals, they were more interested in the cyls. being equal in compression(within 15# of one anouther) Most ran 125 to 135 new dependind on the year as the compression ratio veried but many of your vintage engines run well at 100 to 115#

 

[Clams Canino]

Re: FAO: Clams/Laddies Compression

What Laddies said. Exactly.<br /><br />-W

 

[MercFan]

Re: FAO: Clams/Laddies Compression

Great stuff!<br /><br />Thanx a mil guys <br /><br />So my 120-ish (+-1) is fine

 

[timmathis]

Re: FAO: Clams/Laddies Compression

120 + or - 10% O.K. all day