i want to do a comp test on 40hp BUT

[mar t G]

89 evinrude 40hp o/b<br />BUT, i need to ask a few ?... 1st the tune up sequence has me starting with a comp test OK thats suppose to be easy right? i bought a very nice high end tester that we'll be working with.<br />so here goes.<br /> CAN THIS TEST BE DONE WITH MUFFS??? <br /><br /> warm engine FOR HOW LONG???<br /> remove plugs and wires ground 1st wire to block connect gage to hole that 1st wire goes to. DO I GR. 2ND WIRE WHEN TESTING 2ND HOLE OR CAN I CHECK BOTH HOLES GROUNDING THE SAME WIRE??? <br /><br />now i need to make sure the throttle's held wide open. HOW DO I DO THIS???<br />from the control box or right from the engine.<br /><br />now if i'm using the muffs this is were i turn them back on and crank the engine over at least 4 compression strokes. RIGHT???<br /><br />HOW DO I TURN THE ENGINE OVER??? sense i've disabled the ignition system.<br />i have a remote starter but need to know how to hook it up before useing it.

 

[jim dozier]

Re: i want to do a comp test on 40hp BUT

The test can be done on the muffs. If you do it with the engine cold the muffs are just there to lubricate the water pump. The test can be done on a cold engine, the numbers may change a little if you warm it up to operating temp but its the difference between cylinders as opposed to the magnitude of the numbers that is important. Cylinders should be within about 10% of each other. Don't worry about the throttle being open, that primarily applies to 4-strokes, the 2-stroke cylinder is vented by the exhaust port until it closes. Ground the plug wires or rig a starter bypass switch on the starter solenoid that will turn over the engine without energizing the plugs. Turn over the engine with the plugs out until the compression reading stabilizes (about 5 or 6 seconds).

 

[JB]

Re: i want to do a comp test on 40hp BUT

To Evinrude Troubles and Repair.