Spark plugs in a Merc 2+2

Nitro Owners Forum

Help Support Nitro Owners Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Rich Stern

Well-Known Member
Feb 26, 2000
Reaction score
My 700LXDC has the Merc 115 with the 2+2 idle feature. I took the plugs out today to wipe them down. The lower two plugs were very clean in comparison to the upper two plugs. I assume the lower two cylinders are the ones that do not receive fuel in lower RPM range and that's why they are clean? Anyway, I swapped the upper two plugs with the lower two plugs, with the rationale that the cleaner plugs will run the motor better at idle.

Any reason not to swap plugs like this before tossing them for a new set?

Latest posts