Folks, I am about to do a compression test on my '92 Merc 2 stroke 4 cylinder. I have still not found a pontoon trailer to pull it out of the water so I can work on the carbs (marinas are booked solid with repair work) - see my other thread on that at http://www.marineengine.com/boat-fo...oke-4-Cylinder-won-t-idle&p=652145#post652145
So, would like to do a compression test (nothing better to do). Have read instructions on compression tester that said to:
Warm engine (can't do that since it won't start but did a cold compression test in 1995 and still have those readings 138-140, can't remember what prep steps I did then).
Remove all spark plugs.
Disconnect fuel supply (and drain fuel out of lines and carbs, I know how to do this).
Disable electronic ignition (don't know how to do that but there is a fuse in the cover of the electronic box).
Screw in compression gauge with appropriate adapter making sure adapter end is short enough to not hit piston.
Hold throttle plate open (I think lifting the fast idle lever all the way will do this).
Crank at least 5 compression strokes to get a reading or until reading stops rising.
So, questions: how to disable electronic ignition??,
hold throttle plate open??,
anything I should do with empty spark plug leads?
Can anyone add to above or answer above 3 questions?
Thanks
So, would like to do a compression test (nothing better to do). Have read instructions on compression tester that said to:
Warm engine (can't do that since it won't start but did a cold compression test in 1995 and still have those readings 138-140, can't remember what prep steps I did then).
Remove all spark plugs.
Disconnect fuel supply (and drain fuel out of lines and carbs, I know how to do this).
Disable electronic ignition (don't know how to do that but there is a fuse in the cover of the electronic box).
Screw in compression gauge with appropriate adapter making sure adapter end is short enough to not hit piston.
Hold throttle plate open (I think lifting the fast idle lever all the way will do this).
Crank at least 5 compression strokes to get a reading or until reading stops rising.
So, questions: how to disable electronic ignition??,
hold throttle plate open??,
anything I should do with empty spark plug leads?
Can anyone add to above or answer above 3 questions?
Thanks