1990 Evinrude 120HP weak spark Help Please

"(Update to my recent post

"(Update to my recent post)- Engine runs strong, but recently has failed to reatart when warm on several occasions. Each time it seems to get worse (longer until it would finally start). I changed powerpacks with a good one I already had, and it ran great for a while, then died. Now it won't start at all, even after cooling. I see now that I actually have a very weak spark (visible at night, but not in bright sun).

I have pulled the flywheel. No obvious visible problems with stator or timer base. No cracks/melting.

I have a manual that is supposed to cover until 1990, but my system is totally different from what it describes (single powerpack vs. dual in manual, and different wire colors).

I need this boat running for Labor Day weekend. Can anyone tell me how to test my stator and timer base?

I can order both the stator and timer base on Wednesday and have it by Friday - not really worried about the cost, but I don't want to replace both if it is something else.

Any suggestions or help will be appreciated."

Do a compression test and a pr

Do a compression test and a proper spark check to see if the spark will jump a gap of 7/16" on each cylinder.Testing the spark by laying the plugs on the block is a waste of time--- it just is.

"Remove the spark plugs. Remov

"Remove the spark plugs. Remove the black/yellow wire from either the wiring harness to powerpack connection or from the ignition switch. Perform a spark test incorporating the proper 7/16" gap. If you have proper spark now, the most likely cause is a intermitently shorted ignition switch. If so, replace the switch.

(Spark Tester - Home Made)
(J. Reeves)

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:


..........X1..........X2

.................X..(grd)

..........X3..........X4

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"

"Thanks Joe-

I already trie

"Thanks Joe-

I already tried it with the black/yellow wire disconnected. First thing I did. I will make a spark gap tester, and report he results, but I can tell the spark is quite weak."

"Bill... Assuming that there i

"Bill... Assuming that there is no problem with the ignition switch (black/yellow wire) which you have already checked, my attention would be diverted to the stator. If it should be cracked and/or leaking a substance down upon the powerhead, replace it regardless of whatever ohm reading you may obtain from it."

"I have ordered a new stator.

"I have ordered a new stator. I did the following tests on the old stator. There are three pairs of wires (orange, yellow and brown).

I measured the following Ohm readings (forgot which readings go with which pair): 285, 100 and 1.

Voltage: The following voltage measurements with the starter cranking: 50 VAC (orange pair).

Hopefully, new stator will be in for the holiday weekend."

"I put in a new stator. All t

"I put in a new stator. All the readings seemed the same for the new and old, but with the new the spark jumps almost 3/4" instead of 1/8"!

Motor fired right up and sounds stronger than ever. I will lake test tomorrow,a nd hopefully it won't go back to teh intermittant problem.

By the way, the old stator was the fully-enclosed kind (molded black plastic shell). No signs of any cracks or melting. The new one is Bare - no potting compound at all - just a bit of varnish."