Joe_the_boatman
Chief Petty Officer
- Joined
- Apr 14, 2005
- Messages
- 482
I'm trying to do a leak down test on my '85 60hp Merc 2 stroke (suspected cracked water jacket).
I bought this:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94190
With these instructions:
http://www.harborfreight.com/manuals/94000-94999/94190.pdf
Excerpt:
"4. Position the cylinder to be tested at TDC on the compression stroke so all
valves are closed.
5. Turn the Regulator Knob fully counterclockwise. Connect the Cylinder Leakage
Tester to a compressed air source (not included). NOTE: Be sure the air
compressor?s regulator is set from 7 to 100 PSI. Never operate this tester
with air pressure set higher than 100 PSI, which can damage this tool.
6. Hand screw the Adapter Hose (10) into the spark plug hole of the cylinder to
be tested. Connect the male end of the adapter Hose to the female coupler of
the extension hose.
7. Turn the Regulator Knob (9) clockwise until the Leakage Gauge (6) reads ?0?
(zero) at the end of the yellow band.
8. You can now read the amount of leakage on the Leakage Gauge (6) as a
percentage loss.
9. Test the remaining cylinders to determine which if any cylinders are bad."
Following those instructions really doesn't tell me anything about the motor. Each cylinder, when "zeroed" on the % gauge, yields 15 psi on the pressure gauge.
I hooked up the hose, applied a small amount of air, and turned the flywheel until I couldn't hear the air leaking into the exhaust ports (and saw the % gauge rise). Then I increased pressure as I held the crankshaft in place, and reached 15 psi as the % gauge reached 0.
Compression test reads 100/110/110 psi, so I don't have 15 psi compression. Taking the reading at TDC gives the same result.
Does any of this make sense?
I bought this:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94190
With these instructions:
http://www.harborfreight.com/manuals/94000-94999/94190.pdf
Excerpt:
"4. Position the cylinder to be tested at TDC on the compression stroke so all
valves are closed.
5. Turn the Regulator Knob fully counterclockwise. Connect the Cylinder Leakage
Tester to a compressed air source (not included). NOTE: Be sure the air
compressor?s regulator is set from 7 to 100 PSI. Never operate this tester
with air pressure set higher than 100 PSI, which can damage this tool.
6. Hand screw the Adapter Hose (10) into the spark plug hole of the cylinder to
be tested. Connect the male end of the adapter Hose to the female coupler of
the extension hose.
7. Turn the Regulator Knob (9) clockwise until the Leakage Gauge (6) reads ?0?
(zero) at the end of the yellow band.
8. You can now read the amount of leakage on the Leakage Gauge (6) as a
percentage loss.
9. Test the remaining cylinders to determine which if any cylinders are bad."
Following those instructions really doesn't tell me anything about the motor. Each cylinder, when "zeroed" on the % gauge, yields 15 psi on the pressure gauge.
I hooked up the hose, applied a small amount of air, and turned the flywheel until I couldn't hear the air leaking into the exhaust ports (and saw the % gauge rise). Then I increased pressure as I held the crankshaft in place, and reached 15 psi as the % gauge reached 0.
Compression test reads 100/110/110 psi, so I don't have 15 psi compression. Taking the reading at TDC gives the same result.
Does any of this make sense?