1997 evinrude what should compression be?

[jweb]

Hi Guys,
looking to buy a 1997 -150 with compression at 75-80. I think this is low but seller insists its a low compression motor from factory. I have not been able to confirm or deny this, anybody know where the compression should be? I have a couple of 225- 1993 and they are at 110. May be a bad comparison.

 

[tashasdaddy]

Re: 1997 evinrude what should compression be?

the 6 cylinder do have lower compression than the 2,3 and 4 cylinders. compression guages vary, the way of testing varies. the proper compression testing instructions are in the TOP SECRET FILE. you want the reading to be within 10 % of each other. a Decarb can sometimes bring lower than normal compression back to normal range.

 

[SparkieBoat]

Re: 1997 evinrude what should compression be?

I have a 1996 150 Evinrude Intruder that has 112-118 compression, but I have seen other motors that had compression in the 80s or 90s and ran very well. That motor has o-ring seal in the heads and they are easy to replace and do a good de-carb, but only if you already owned the motor, sounds like that motor has lots of hours on it to me, but I could be wrong. I passed on a few motors with lower compression before getting mine.

 

[SparkieBoat]

Re: 1997 evinrude what should compression be?

I just remembered that my 150 is the GL model and came with the high compression 175HP heads, below 80 still sounds low to me, I would expect high 80s to mid 90s at least. Tash is correct about the de-carb though..can really make a diifference

 

[jweb]

Re: 1997 evinrude what should compression be?

Please explain Decarb. I am not sure what that means, Thanks for the feedback

 

[jonnymarquis]

Re: 1997 evinrude what should compression be?

check out the top secret file for that question http://forums.iboats.com/showthread.php?t=299680