1972 evinrude 125hp

[paedbo]

Recently replaced pulse pack and sensor. Here is my question, i have done a search on the forum for the air gap on the sensor i know its supposed to be set to .028 ( clymer manual says the same ), I set it to 0.028, put everything back together and the engine will not fire, but if i set the sensor air gap to about .020 the engine does fire and runs on the hose. the surface to measure the gap isnt quit flat its rounded off alittle. i am using a .025 + .003 shim to measure the gap. Am i doing something wrong here? and what will happen if i leave the gap set to 0.020?

 

[Joe Reeves]

Re: 1972 evinrude 125hp

Paedbo.... The gap should be set to .028 as you state. I couldn't say for sure what the result would be if the gap was any closer, but it stands to reason that a closer gap would have the ignition fire somewhat sooner which would affect the timing. That might cause pre-ignition.<br /><br />There are four (4) lobes on that rotor. Check the gap on all four rotor lobes and set the gap to .028 on the lobe with the most clearance, such as one lobe may be a tight .028, the next may also be a tight .028, the next lobe may be closed down to .023, etc.<br /><br />You don't want one at .028, and the other three lobes wider than that.<br /><br />Note... In checking the spark, have the s/plugs out to obtain the highest rpm available.