I'm working with a small engine mechanic, trying to get an old W5019 running again. He pulled the head and cleaned up the valves, which were badly fouled. He did a leak down test and it was holding to 90 psi. When he does a compression test he is only getting 25 - 30 psi. Does anyone know what kind of compression we should be getting with this engine? Thanks.
Do the test again with the valve lash opened up to around .040" to defeat any decompressor that may be fitted.
Not familiar with that engine
But without the decompression you should be seeing 100psi .
The only numbers I have ever seen for an engine with the valves set properly was from Kawasaki and they quoted 60 to 95 psi for the FR series.
The range is that wide to cover the allowable ,002" variation in valve lash
