1998 70hp mercury tracker, low compression

[Privateer18]

What would cause an engine to show low compression on the # 3 cylinder unless the carb is covered by hand?

 

[racerone]

Open or closed carburetor makes no difference on a compression test.--Something weird is going on here.------Serial # should be posted !

 

[Faztbullet]

It sounds like you have engine problems...pull the head and inspect.

 

[Faztbullet]

Sorry meant exhaust plate...thinking OMC when replied

 

[racerone]

Removing the exhaust plate ( 20 bolts ) allows you to inspect piston / rings.-----That would be my next step.

 

[Marine Services of Las Vegas]

A broken reed valve?

 

[racerone]

Reed valves have nothing to do with compression in the cylinders !