Y in spark plug code

[jjjm]

48 hp johnson calls for QL78C plugs, Engine has QL78YC in now, what does Y stand for and will it have any effect on engine using this # plug?

 

[Walker]

Re: Y in spark plug code

Standard projected nosecone, whatever that means<br /> http://www.championsparkplugs.com/sparkplug411_champion.asp

 

[Reel Appeal]

Re: Y in spark plug code

Standard projected core nose.Its referring to the center electrode and the distance projecting past the end of the threads.A plug too long would contact the top of the piston(possibly) causing damage.A different letter other than Y(like M) may refer to an extended tip/electrode (like a specialized racing plug),etc.

 

[seahorse5]

Re: Y in spark plug code

According to the factory recommedations, NO 48hp uses a QL78C plug. 1989 and later use the QL78YC with the extended nose and the earlier models of the 48 take the QL77JC4.<br /><br />According to the former OMC and now Bombardier, the only official spark plug chart is the one published each year in the Parts and Accessories Guide.

 

[rickdb1boat]

Re: Y in spark plug code

Seahorse is right. 1980-1988 48's call for a QL77JC4. 1989-2001 models call for the QL78YC. That is the recommendation and I would follow it. The only exeption I would make is in the gap. It calls for .030 formally. but I have found that .040 makes them run better at low speed and idle better, too. Just my experience..

 

[jjjm]

Re: Y in spark plug code

Operation and Maintenance Manuel from omc that I got when i bought the boat this year shows 1994 48hp spark plug specifications as QL78C with.030 gap or if used at sustained high speed QL16V fixed gap. No mention of "Y" in their specs. Manuel was published in 1993 so it does go with this motor

 

[seahorse5]

Re: Y in spark plug code

Back in around 1995, the then OMC along with Champion Spark Plugs, redid all their previous recommendations. A lot of the motors received different spark plug suggestions, and new plugs were added to the lineup, such as the "Y" style extended nose plugs.<br /><br />Service bulletins were issued and the official spark plug charts were changed. <br /><br />QL78C plugs will not hurt your motor but you will get better drivability with the QL78YC style of sparkplug.