Re: best spark plugs??
Volvo penta 5.0GXi. the shop manual calls for 2X 3858996. When i google this, i get Champion RS12PYP. So i guess i need equivalent to those. Anyone have a suggestion for plugs?
Hi there, originally your engine would have come with AC 41-932 which has now superseded to AC 41-993. When it comes time to change the plugs, Volvo's service number for your engine is 3858996 which translates into Champion RS12PYP. Mercruiser is flopping back and forth between AC and NGK for the same engine comparison of yours.
You have many options to choose from and the theories vary of best to worst here on iboats. AC and NGK go back and forth as being #1 while champions typically seem to come in last place between the two.
You could go with anyone of these,
AC DELCO 41-993 - Alternative spark plugs or any one of these
Champion RS12PYP - Alternative spark plugs and probably be okay.
All the plugs mentioned in the links can be very expensive if you do not do your homework. Marine dealers may charge almost $20.00 each but if you find the plug you want to use, you should be able to find them as low as $5.00+ each. Especially the AC's.
The most impoertant thing to know is that the iridium spark plugs are sensitive to gapping and are easily damaged if done wrong. The video linked below shows you the correct way to do it. At the price of the plugs, you'll want to watch the video.
Spark Plug Gap - NGK Spark Plugs - Tech Video - YouTube
Hope this helps, good luck.
