I purchase a tool to check compression on my 701cc engine for my super jet. When doing the test, should I take out both spark plugs at once and test each one? Or should I take out one spark plug, test the compression and put back the spark plug before I test the next one? What is the proper way? Also what should my compression be? Also, how long should I hold the green starter switch to properly test? Thanks!!!
Compression Test for my SJ
- Thread starter magic74
- Start date
Shifty
- SuperJet Thursday -
- Location
- Austin Texas - Lake LBJ
Compression will vary but as long as compression is within 0-7psi? between each cylinder you should be in good shape. Stock compression is at 150psi.
Perform the test with one plug in place, throttle fully open (choke off) and crank until the needle stops climbing.
Make sure you ground your plug wires to the block, etc.
If your compression tester is a really cheesy one, you will be wasting your time.
Perform the test with one plug in place, throttle fully open (choke off) and crank until the needle stops climbing.
Make sure you ground your plug wires to the block, etc.
If your compression tester is a really cheesy one, you will be wasting your time.
Freakrider
X247
- Location
- Tampa Bay area
also hold stop button in while cranking to ground out/eliminate spark/ protect cdi...
good call peaple never do that
Mile9c1
X-H2O.com
- Location
- Grand Rapids, MI
I don't think your method matters, just be consistent. A stock twin engine usually comes with around 150psi.
- Location
- San Jose, CA
i must be really dumb, but if you are holding the stop button in, how is your motor going to crank? you crank the ski with the 'start' button, so how can you hold the stop button in at the same time? again, i must be dumb
sorry.
- Location
- San Jose, CA
i must be really dumb, but if you are holding the stop button in, how is your motor going to crank? you crank the ski with the 'start' button, so how can you hold the stop button in at the same time? again, i must be dumb
according to this, if you press the stop button but press the start button, it will crank, just not spark... i guess this is correct?
http://www.x-h2o.com/showpost.php?p=194130&postcount=3
It will crank ! The stop button only serves to defeat the CDI from making spark. The start button only operates the solenoid to spin the starter. You have to have the lanyard on because it is a dual switch that acts the same as the stop but also defeats the start button.
Hitting the stop button is the safest method, grounding the plugs when removed will help protect the CDI & coil but then you will have an open spark in the bilge. This can ignite any spilled fuel vapor.
Hitting the stop button is the safest method, grounding the plugs when removed will help protect the CDI & coil but then you will have an open spark in the bilge. This can ignite any spilled fuel vapor.
WaveDemon
Not Dead - Notable Member
- Location
- Hell, Florida
yes, you press both at the same time