1997 Evinrude Ocean Pro 175 What are low compression heads and do I have them.

[gwgautney]

I just bought a 20foot pro line with a 1997 Evinrude 175 Ocean Pro. E175EXECD I checked compression and they were all right around 90. I thought that was low but then read someone else's post and they mentioned something about low compression heads. Just wanting to know what the difference in those and regular heads and also if I had them. I am also looking for any info on motor that anybody has.

Thanks

 

[gwgautney]

...

 

[bob johnson]

I don't think there is such a thing as low compression heads for that motor. what the confusion is, people will call the RESULT of something they do, as if it was a design!

the 60 degree looper blocks on the 90s in V6 had two configureations, a 150 hp model and the 175 hp model... they were MOSTLY identical... and the heads easily interchange....but only because the bolt pattern is the same... the 150 hp heads most likely have a larger chamber...The 90 and 115 hp version in V4 have different chambers sizes from each other). the difference between the 150 and the 175 is porting in the cylinder sleeves, carbueration, and head chamber size....

90 psi is not a "LOW" compression reading for that model 175 hp!! factory compression when new was probably maxing out about 100-110 only.

the motor could be consider just fine if the reading are all within 10 psi( factory says 15% is OK)

bob

 

[gwgautney]

awesome thanks Bob where can I find info on what type of fluids I need to use was just curious if I need to run a particular oil or if regular two cycle quicksilver oil is fine also I want to change impeller and gear oil so wanting to know what oil to use

 

[gwgautney]

2 stroke oil