Need help on Compression Test on a chirs Craft

[jciv22]

Hi,<br /><br />I was wondering if someone can tell me the pressure should be on a 2.5l Chris Craft 86. I got 110 PSI on 1, 100 PSI on 2, 110 PSI on 3, 100 PSI on 4. Reason to do test because milky oil. I am think that it is the headgasket but not sure after reading some of the post. <br /><br />Thanks for the help.<br /><br />JC

 

[Haut Medoc]

Re: Need help on Compression Test on a chirs Craft

They are low but acceptable for now. I would look for a cracked/porous exhaust manifold/riser. How long did it take for the oil to get milky? Is this a fresh water or closed water system? Oh, welcome to iboats .....JK

 

[Bondo]

Re: Need help on Compression Test on a chirs Craft

If that motor was Healthy,......<br />Those #s would be Alot Closer to 150psi.....

 

[jciv22]

Re: Need help on Compression Test on a chirs Craft

Thanks guys,<br /><br />Fresh water, I was at the lake and the engine start to heat up. I turned it off and temperture was at 210. I will check the exhust.<br /><br />Thanks again<br /><br />JC

 

[Alumarine]

Re: Need help on Compression Test on a chirs Craft

You might want to try another compression gauge and see if the numbers change. Those numbers seem too consistant for a head gasket alone.<br />Throttle wide open and crank it over a few times when doing the test.

 

[jciv22]

Re: Need help on Compression Test on a chirs Craft

Marc C,<br /><br />Thanks for the response and all other guys too. You mention the throttle should be wide open. So you can crank when the shefter is at wide open. Maybe that is my problem. I did not have the throttle at wide open. It was in N.<br /><br />Again Thanks, this is a great web sit.<br />JC

 

[Alumarine]

Re: Need help on Compression Test on a chirs Craft

Nuetral is good but the throttle should be wide open preferably with the engine warm and all the sparkplugs out so it turns over well.

 

[Dunaruna]

Re: Need help on Compression Test on a chirs Craft

And use a good battery, a battery that fades can make a difference between the first crank and the last.

 

[jciv22]

Re: Need help on Compression Test on a chirs Craft

Hi Marc,<br /><br />Does this mean that I have to disconnect the throttle cable to have it wide open. <br /><br />Thanks<br /><br />--------------------<br />1974 Glastron V179<br />Mercruiser 140<br />Home Port: Lac du Bonnet, MB, Canada

 

[Don S]

Re: Need help on Compression Test on a chirs Craft

Just move the lever to full throttle but leave the drive in neutral.<br /><br />Have a look at this link. It's info on a compression check.<br /><br /><br /> http://www.boatfix.com/merc/Bullet/97/97_25.pdf