70HP 1983 Spark plug Question

[jeffasmith]

The OMC Dealer sold me Champion L77JC4 plugs for my motor, which my Selco general manual says are correct. But the flag (small white tag) on the number one cyl wire says Champion QL77JC4. So what is the difference between these two plugs other than the obvious one has the addtional letter "Q"? Any harm in running either plug over the other?

Much appreciated, Jeff

 

[jwbmarine]

q is a suppresion plug....either,..is perfectly fine....i dont even stock the l77's any more.

 

[vics]

QL77JC4 are the same as L77JC4 except that they have low resistance, inductive radio interference suppression

The Q series are recommended for all VRO or OMS motors otherwise either can be used, and are both listed for your engine.

What you must avoid with OMC CD ignition systems are plugs with ordinary resistive suppression .. Mostly they have R as the first letter.

(Sometimes NGK resistive plugs eg BR7HS-10 are sold as equivalents ... they are not. Inductively suppressed NGK plugs have a "Z" in the number eg BZ7HS-10)