compression test on 1978 evinrude 75 hp

[derrhalt]

can anyone help me with providing the correct steps for testing compression. motor has been sitting for 2+ years and turns over but do not know what else i need to do to get accurate test. this is what i did.

1. new battery connected
2. disconnected and removed all 3 sparks
3. screwed in compression tester in one cylinder
4. turned key for 5-10 seconds

No reading!! Do I need to spray anything in cylinders or add any type of lubricant to get things moving or am I screwed? I have been watching and reading everything and have info overload. What am I doing wrong?

Should i not use ignition....do i use choke or have throttle wide open?

Any help would be greatly appreciated.

 

[F_R]

Re: compression test on 1978 evinrude 75 hp

You are doing it correctly, except you should either ground the spark plug wires or attach them to a spark checker. Not doing that is torture on the coils. Squirting oil in the cylinders is cheating and will give false readings. On the other hand, it will give some protection against dry cylinders from long storage. Either way, you should have gotten a compression reading. Choke and/or throttle have nothing to do with it (on a two-stroke, as you have).

1. You have NO compression on that cylinder, or

2. There is something wrong with your gauge or the way you have it installed.

Have you tried it in other cylinders?

 

[emdsapmgr]

Re: compression test on 1978 evinrude 75 hp

Try your compression gauge on your car/lawnmower to make sure it works.

 

[Bosunsmate]

Re: compression test on 1978 evinrude 75 hp

Put your thumb over the sparkplug hole and get someone to turn the key or hook up a jumper to the solenoid, if you feel any pressure your gauge is broken

 

[boobie]

Re: compression test on 1978 evinrude 75 hp

Bad gauge.........