120 looper bland performance (better than before but not good enough)

[Walker]

Re: 120 looper bland performance (better than before but not good enough)

There are plenty of those motors running on QL77JC4's and running fine. That's the plug that was recommended before the change.<br />Forgot the Q

 

[Joe Reeves]

Re: 120 looper bland performance (better than before but not good enough)

I've looked over every post/reply above and see nothing definite about the compression and spark, just generalities.<br /><br />Exactly what is the compression of all cylinders? And with the spark plugs removed, the spark should jump a 7/16" gap with a strong solid wide blue lightning like flame.... a real SNAP.... on all cylinders! Does it?<br /><br />EDIT: Sorry, I see where the compression was listed as 125, 125, 125, 124. Strange that I overlooked that.<br /><br />Spark plugs should be Champion QL77JC4 plugs, gapped at .040. Are they? And yes, I know the book says .030. If you have them set at .030, at least give a try to the .040 setting to see if there's a performance difference.<br /><br />That 1990 120/140 model changed its stator to a 3/9 ampere output so there's not much danger that it's melting down (voltage drop to the powerpack), but look under the flywheel anyway and check to see if any portion of that stator might be cracked, melting down a sticky substance on the timer base and block, whatever. Always good not to assume and chance overlooking something.

 

[Tacklewasher]

Re: 120 looper bland performance (better than before but not good enough)

Joe. First post listed compression numbers <br /><br />

125 125 125 124 psi

 

[alden135]

Re: 120 looper bland performance (better than before but not good enough)

Originally posted by Joe Reeves:<br /><br /><br />Exactly what is the compression of all cylinders? And with the spark plugs removed, the spark should jump a 7/16" gap with a strong solid wide blue lightning like flame.... a real SNAP.... on all cylinders! Does it?<br />

I would not describe what I saw on the spark test like mentioned above. I made a spark tester from another members example. I would describe the spark as white and thin. I've read some posts which say "blue" spark, and then others say "white, lightning like". What gives? Also, when I changed the TB this spring I did not see any goo leaking from the stator.<br /><br />#1 125 #2 125 #3 125 #4 124<br /><br /><br />EDIT: Joe, I read my post and want to make sure you know I'm not questioning your expertise on the spark thing. Also, the plugs are at .030

 

[Joe Reeves]

Re: 120 looper bland performance (better than before but not good enough)

A 7/16" gap with a strong solid wide blue lightning like flame is what is needed.<br /><br />The next range down (failing spark) would be a yellow spark. I've never seen a white spark but I would assume that would be below the yellow range.<br /><br />A weak thin spark of any color indicates a ignition system in need of repairs.

 

[G DANE]

Re: 120 looper bland performance (better than before but not good enough)

I think Joe got something. If you want to further investigating spark, try to enlarge gap slowly and see how long they will jump. Ive tryed corrosion on plug lead terminals made one whitish, but it didnt jump as far as the other. I still believe somewhat in the reed problem possibility though.