Compression test with outdrive off

[Squab]

I have a 1989 merc that is currently winterized. I took the outdrive off last week and am wondering if I can perform a compression test with the drive off. I also have all the hoses lose and system was filled with anti-freeze. If I run the compression test with no water going into the system is that bad for the engine?

 

[mkast]

Re: Compression test with outdrive off

A compression test should be performed with the engine at operating temperature.

 

[Bondo]

Re: Compression test with outdrive off

A compression test should be performed with the engine at operating temperature.

Ayuh,... I Agree, but doin' a test on Squab's motor won't hurt a thing, 'n will give a vague general statement to it's general cylinder/ valve condition....

It ain't startin',.. The drive is off,.. Ya don't need water.....

 

[ziggy]

Re: Compression test with outdrive off

compression test link..

http://www.boatfix.com/merc/Bullet/97/97_25.pdf

 

[Squab]

Re: Compression test with outdrive off

Bondo- Will it affect the water pump that is in the front of the engine? Below the Thermostat? Will me turning over the engine force all of the antifreese that I put in it for winter. Not sure if the cold is over yet here,,, Jersey

 

[Squab]

Re: Compression test with outdrive off

Hey Bond-0, I also forgot to tell you that I have the Carb off for repair. Will this affect. Since I am not looking for ignition then it should not matter right. Just need oil and battery.

 

[Lou C]

Re: Compression test with outdrive off

A cold engine comp test will not be accurate. If you want to get meaningful results you need to reinstall the carb, hook up a water hose to the thermo housing, get the engine well warmed up and then check the compression. Yes you can do it with the drive off. Just need to get water to the thermo housing. If you do it with a cold engine the #s won't be representative.

 

[Bondo]

Re: Compression test with outdrive off

Bondo- Will it affect the water pump that is in the front of the engine? Below the Thermostat? Will me turning over the engine force all of the antifreese that I put in it for winter. Not sure if the cold is over yet here,,, Jersey
Hey Bond-0, I also forgot to tell you that I have the Carb off for repair. Will this affect. Since I am not looking for ignition then it should not matter right. Just need oil and battery.

Ayuh,... As I said, it won't be the Most accurate, but it won't Hurt anything either...
If there's abit of spillage of the antifreeze, So what, it don't Hurt anything...
Air don't freeze...

 

[jerryjerry05]

Re: Compression test with outdrive off

No water in = no water out.A cold compression test is better than no compression test.J

 

[Squab]

Re: Compression test with outdrive off

The reason I am asking about the antifreeze is because I am not sure if the temps are going below freezing again in my area.. Dont need a cracked block..

 

[Alpheus]

Re: Compression test with outdrive off

If some AF happens to pump out while your turning the engine over it wont hurt anything. As long as you dont introduce new water to the system you will be fine. Like Bondo said "air don't freeze". You could dump all of the AF out right now and be perfectly safe...

 

[Squab]

Re: Compression test with outdrive off

Alpheus,
Thanks for better explaining the situation