quick compression test question

[SirEnvy]

I went to the hot page, and found out how to do a compression test(I had an idea) but do I really need to disconnect fuel line and rig a jumper to the starter? I plan on getting a screw in compression test, and plan on doing the test myself. The motor is on boat now with full electrical running to motor.

 

[Will Bark]

Re: quick compression test question

You don't need a jumper if you have a friend to hit the starter switch while you test each cylinder. Remove all spark plugs and test one cylinder at a time You disconnect the fuel line so that you aren't pumping gas thru the carbs and into the crankcase. Good luck.

 

[SirEnvy]

Re: quick compression test question

You don't need a jumper if you have a friend to hit the starter switch while you test each cylinder. Remove all spark plugs and test one cylinder at a time You disconnect the fuel line so that you aren't pumping gas thru the carbs and into the crankcase. Good luck.

Thanks!

 

[jonesg]

Re: quick compression test question

Thanks!

I don't usually follow any precautions, leave the fuel lines, I don't bother grounding all the plugs, then again I don't crank it for more than 3-4 revs.
I do it on my own, the guage screws into the hole and holds the reading until you press the pressure relief button. It can be made into a very complicated proceedure.
Ever see anyone do all that stuff when they compression test their car?
Use common sense, don't stand in front of the plug holes with a lit cig in your mouth.
boom

 

[SirEnvy]

Re: quick compression test question

I don't usually follow any precautions, leave the fuel lines, I don't bother grounding all the plugs, then again I don't crank it for more than 3-4 revs.
I do it on my own, the guage screws into the hole and holds the reading until you press the pressure relief button. It can be made into a very complicated proceedure.
Ever see anyone do all that stuff when they compression test their car?
Use common sense, don't stand in front of the plug holes with a lit cig in your mouth.
boom

Thats what i thought, I never persoanlly seen anyone do a compression test but I have seen videos on it. I knew the obvious(take out plugs, or take off plug wires, and do one at a time) but I saw the secret forum and thought I would ask...thanks guy! I am going to do a compression test to answer my older forum post.

 

[AlTn]

Re: quick compression test question

If you don't disable the ignition system and get stray voltage to the ecu or transmission control module on modern cars, don't be surprised when you get check engine warnings or erratic shifting.

 

[SirEnvy]

Re: quick compression test question

If you don't disable the ignition system and get stray voltage to the ecu or transmission control module on modern cars, don't be surprised when you get check engine warnings or erratic shifting.

Thanks for the information, never knew that...but luckily my boat doesnt have an ECU