How often do you change your center fire plugs?

[hotrod53]

I'm going on year 4 on these plugs. They look good and the Merc 500 runs pretty well but five been noticing it stalling a bit more from idle to gear. I'm sure that I could use a few more RPMs too, I just had the throttle and shifter cable replaced. How often do you replace these?

 

[quicktach]

If the plugs are clean, the insulators ok, some good post left, and regapped, they should be fine to keep going. Otherwise, you're doing OK at 4 years!

 

[Chris1956]

I change them whenever I have a running issue with a motor. To be truthful, that has never helped, as the surface gap plugs last a long time, and I was guessing, at the problem. what is wrong, with your motor?

In your case, let a sleeping dog lie....

 

[gm280]

I run surface gap plugs in my inline 6 115HP Mercury for over ten years and they never ever gave me any problem...

 

[Mi duckdown]

surface plugs last a LONG time unless you crack the ceramic

 

[hotrod53]

No real issue with the motor other than stalling when going from neutral to forward when cold. I just replaced my throttle cable, shifter cable, and main wiring harness so the box has recently been all apart. A friend of mine set up the cables and adjusted the idle, it may just need a few rpms.