Saving Old Seagulls

I have just ordered a couple of new plugs for my Seagull 90. The plug in it at the moment... and it runs well is a NGK A7
I have ordered a couple of NGK A 6 plugs....
What is the difference if any?

Thanks... all info welcome.

Mark

Hi Mark,
The 6 is hotter than the 7.
The upside of a hotter plug is that it will keep itself clean by burning off the oil deposits, but one step up or down is not going to make a big difference. The A6 is thr recommended plug.

Dave.

That’s great because I have just got two! A6..
I did wonder what the difference was if any ... that’s great, thank you.

Mark