What spark plugs are you running (spark plug #) ? 2000 Stock 502 mag/mpi

I have installed RV15YC4 Champion spark plugs gapped at .045 in many different big block powered boats and they work very well. The extreme projection on the nose gives the spark plug a wide heat range and the plug is designed for a larger plug gap. Thats good, because with the long spark duration of the breakerless induction ignition, a wider gap really lights off the air/fuel mixture well between idle and 5,000 rpm. They are very easy to find at automotive parts stores because they are such a common plug (probably Champions biggest seller).
Sincerely
Dennis Moore

Thanks Dennis!

I had the exact same engine in my last boat. Had some problem with rough idling. Switched to Rapid Fire (#1 I believe) and MAN did they smooth the engine right out! Great acceleration and high end too.

Same here ,,, rapid fire #1 ,,, cleaned up my transom to.

Another vote for Rapid Fire #1. Did clean up the rear end on my 27' fountain. In addition to the plugs I have also set the timing to
12 deg advance (32 total advance), installed a K&N air filter , and added an EMI exhaust. These changes have really woke up the stock 502 carb motor.

ttt

3/15/03 post hoe'in huh

No but a friend of mine wants to know about advanceing timimg on his 502 mag so I sent him to the tech site and hioe he will see these. Greg