spark plug question 50 rude 89

[Cpt Quint]

purchased 2 that matched in the book. <br />champion QL78YC are what I purchased but I pulled <br />out champion QL78C. <br /><br />What does the "Y" mean and how different are these?

 

[Paul Moir]

Re: spark plug question 50 rude 89

The 'Y' means it has a projected nose. Compare the two plugs and you'll see that the insulator and electrode on the Y plug sticks out while the QL78C doesn't. My sources indicate the QL78YC is the correct plug too. I think the QL78C was once used on OMCs, but they changed the recomendation to QL78YC and I belive Champion discontinued the QL78C.<br />Otherwise, no difference.