Compression for 91 Evinrude 200HP?

[Alsunbird]

I'm getting 90 on all cylinders, is this to low.<br /><br />Thanks...Al

 

[petryshyn]

Re: Compression for 91 Evinrude 200HP?

Sounds low but suspicious. How many 'hits' are you giving it? The odds are that a cylinder failure wouldn't occur in all cylinders at one time and be even as well. Maybe you have a defective gauge. Hook the gauge to someone's shop air and compare to their compressor gauge, or just borrow one and try again...<br />

 

[Alsunbird]

Re: Compression for 91 Evinrude 200HP?

Thanks for quick reply, I will try what you said. Four or more Hits.<br /><br />Thanks...Al

 

[petryshyn]

Re: Compression for 91 Evinrude 200HP?

Thats 5 - 7 hits with WOT.(same number of hits per cylinder) Also be sure to have all plugs removed before starting, and be sure the battery is up in charge (slow cranking results in low readings) One more thing that never seems to get mentioned.....DISABLE THE IGNITION SYSTEM. An ignition system can be severely damaged if operated 'open circuit'(no plugs attached) Not to mention the pain when you get zapped! There are many ways to disable the ignition. The recommended way is to disconnect the signal generator coil(alias: sensor, charge coil assmy., pickup-coil) There are many ways to disable ignition.see your manual. If you're not sure and don't have a manual, simply ground all plug-wires to block.<br />

 

[clanton]

Re: Compression for 91 Evinrude 200HP?

It had app 100 psi when new. I would put the engine tuner thru it for a decarb, and be concerned about the VRO2.

 

[Alsunbird]

Re: Compression for 91 Evinrude 200HP?

I did the decarb thing last year and had VRO removed, the 90 psi that I'm getting is with a warm engine, all plugs removed and WOT. I poured some oil into each plug hole and got 100 psi.(always even compression) What do you gus think. <br /><br />Thanks...Al

 

[petryshyn]

Re: Compression for 91 Evinrude 200HP?

Did you try a different gauge? I wouldn't get too concerned with your readings unless you're thinking of purchasing this engine. If this a deciding factor for a purchase, then I'd get to the bottom of it by consulting the manual.(should do that anyway)You're readings are even....thats important. Some increase is normal when adding oil to cylinders. If you are not experiencing hard starting and low power, I certainly wouldn't pull it apart.<br />

 

[clanton]

Re: Compression for 91 Evinrude 200HP?

Good to go.

 

[clanton]

Re: Compression for 91 Evinrude 200HP?

Good to go.

 

[Dunk]

Re: Compression for 91 Evinrude 200HP?

The OMC loopers are all in the 90-100lb range. The difference between 90 and 100lbs can just be the particular gauge you are using. The fact they are all alike is what you want to see..

 

[Alsunbird]

Re: Compression for 91 Evinrude 200HP?

schematic, I checked my gauge like you said with my air compressor and checked-out ok. <br /><br />Thanks to all of you for your time and great advise(down to earth), I only been boating for a year and half and glad I found this site a last month.<br /><br />Thanks...Al<br />