leak down test on a 2stroke?

[ozarkjeep]

im registering low compression, and trying to find where its going.<br /><br />can I pressurize the cylinder to detect where the leakage is?<br /><br />at what postion should the piston be in?<br />near the plug or a the bottom of the bore?<br /><br /><br />My luck is there is a trench akin to the grand canyon in a cylinder wall, but Im hoping this could be a head gasket problem since my water flow seems to be awry also.<br /><br />1988 50HO 2 cyl FORCE<br />top cylinder 45psi<br />bottom 65 psi

 

[JB]

Re: leak down test on a 2stroke?

Howdy, Ozarkjeep. Don't bother with a leakdown. It wont tell you anything useful this time. You have both cylinders in terminal low compression. The most likely cause is carboned-up stuck rings.<br /><br />If you can get it to run try decarbonizing it, two or three times if necessary. That might bring them back to over 100lb with difference of less than 15%. If that doesn't work you're looking at an overhaul anyway so you might as well pull the head and have a peek. Then decide whether to overhaul or replace.<br /><br />Sorry I can't be more optimistic.<br />JB

 

[ozarkjeep]

Re: leak down test on a 2stroke?

thanks!<br /><br />im not overly optimistic, just trying to buy a little more time so i can find another 50hp ob in the fall season<br /><br />when I remove the head what do I look for?<br /><br />ring ridge? grooves ( typical stuff?)<br /><br />thanks

 

[JB]

Re: leak down test on a 2stroke?

See your other post.