Weird johnson compression issue

[anesthes]

I've got thisold 50hp electric shift Johnson. Bottom cyl has 0 compression.<br /><br />If I put my air hose on it however, it leaks out the carb. When I turn the flywheel, it closes and there is no leak.<br /><br />Now. If the cyl was dead, you'd think it would leak down exhaust, out head, etc.. 125psi air hose. But it doesn't. Yet you crank it all day with the electric starter, and no compression on that cyl.<br /><br />Any insight?? <br /><br />-- Joe

 

[OBJ]

Re: Weird johnson compression issue

If you get 0 compression on the cylinder then the cylinder is dead. With that much air pressure, you've probably lifted the reeds to let the air blow out the carb and in doing so, probably damaged the reeds. When you bring the pistion back up, your covering the intake ports so that stops the air on that side. Why you don't see any out the exhuast? Probably getting out there to but through a much larger opening than the carb throat. Maybe won't notice it as much. Pull the head and have a look at the cylinders.

 

[R.Johnson]

Re: Weird johnson compression issue

Of course your main problem is no compression, You should not have been able to damage the reed's with #125 through the spark plug hole, after all, their under compression on every down stroke. You can't lift the reed's with air pressure, and if you could, the reed stop's would stop their travel before any damage