spark plug info / suggestion

[bleedblue94]

1983 175 johnson. I have had ngk buhxw-1 plugs in it for awhile. These are the ngk surface gap eqivanlant to the champ qul77v plugs. They have fouled up after a year of use. The shop manual calls for champ qul77v or ul77v (both buhxw-1 equivalants), however in doing reseach I have found many suggest this plug for more WOT use, and instead suggest ql77jc4 for more low rpm use. Is this kind of hearsay info correct? The current ngks also seem to always have a wet and black appearance as if there isn't a complete burn. Thanks for the input

 

[Joe Reeves]

Re: spark plug info / suggestion

Personally I don't like the Jap plugs, and in my OMC books, the recommended s/plug are the Champion QL77JC4 plugs which in my opinion would provide you improved performance.

Gap them at either the original recommended gap of .040 or the later revised recommended gap of the late 1990's of .030, whichever works out best for you.

 

[bleedblue94]

Re: spark plug info / suggestion

Weird how two different omc shop manuals say to use a different plug, although I wonder if yours is newer and they just updated it to show a different preferred plug for the motor, either way thanks. I will prob get the ql77jc4 plgs and rn them at. .035

Thanks

 

[Vic.S]

Re: spark plug info / suggestion

Weird how two different omc shop manuals say to use a different plug, although I wonder if yours is newer and they just updated it to show a different preferred plug for the motor, either way thanks. I will prob get the ql77jc4 plgs and rn them at. .035

Thanks

Joe is the one who generally knows best!

The most recent list I have for plug types is http://continuouswave.com/whaler/reference/BRP/SparkPlugChart2008.pdf but that shows UL77V or QL16V

Most makes use NGK plugs ... not easy to get champion plugs in The UK but everywhere stocks NGK!
Most important usually is to avoid NGK resistor plugs which are sometimes offered as equivalents to the Champion "Q" types which are inductively suppressed.

If you are stuck with NGK plugs then BZ7HS-10 is the equivalent of QL77JC4 (B7HS-10 is the non suppressed version ... dont use BR7HS-10 which is the resistor type)