Re: Merc. compression check
1. Warm up motor to normal operating temperature. REMOVE the key from the ign.
2. Remove all spark plugs.
3. Shift the control box to FWD and apply throttle until the carbs open fully.
4. Screw your compression gage into the 1st cyl to be checked.
5. Find the starter solenoid, within the powerhead. Then, locate the yellow wire which connects to one of the small terminals on the solenoid. Attach one end of an automotive remote starting switch to the yellow terminal on the solenoid; attach the other end of the switch to the Positive terminal on the battery.
Note: at your own risk you can "jump" from the "hot" (battery side) of the starter solenoid, to the yellow terminal, with a shorting wire. Be aware that any sparks could ignite fuel vapors so best done in a well-ventilated area. You can also make your own switch setup with any suitable type of switch, wiring, and a couple of alligator clips.
6. Using the remote switch (or jumper), energize the starter solenoid. Remember you're in gear so stay away from the prop, it's gonna turn!
7. Crank for 5-10 seconds, which should be sufficient for the compression gage to come up to its maximum reading. It's time to stop when the gage needle no longer increases. Don't crank the starter for much longer than this, and give it a bit of a rest between readings. The time you'll take swapping the gage over is probably enough.
8. Depressurize the compression gage and repeat on that cyl if desired. Repeat for the remaining cylinders.
Note that the water pump should still have some moisture inside and this would typically be enough to lubricate while you're doing compression checks. If you're doin' it dry, it certainly wouldn't hurt to slap your "earmuffs" flusher on the lower unit and give it just a trickle of water. Just saves a bit of wear-and-tear on the impeller.
That should Git 'er Dun. Hopefully compression readings are no more than 10 psi apart from each other. If they are, a decarbonizing treatment with Seafoam, Techron, etc may be in order.
Last thing, don't forget to shift back to Neutral when you're done!
HTH...........ed
