mosh

I'm still learning about glow engines and how they work but what are some of the best glow plugs to run in a 3.5 K&B outboard motor? I'm running 40% nitro now, how much higher could I go without wearing things out and if I did what would wear out first?[sm=confused.gif]

piper_chuck

My Feedback: (12)

If it's one of the newer ones you can use just about any plugs. If it's an early engine, you should use a short plug such as a K&B 1S, or use an extra washer under a standard length plug. The difference is the older engines have a thinner head and a standard plug is too long. I've seen lots of people recommend McCoy MC59 plugs for lower nitro. I use MC-9 plugs for higher nitro. I'm having good results with the MC-9 plugs in all my boat engines using 50% nitro.

mosh

I have the newer motor with the 13mm.

ob nut

My Feedback: (1)

I'm running 65%, MC9 plugs. Have used K&B L1's also. I've heard of people running 70% in the 3.5's. All things wear over time. It all depends on they are treated. Run the motor too lean for too long, there goes bearings, piston/sleaves, etc.. When done running for the day, get the last bit of fuel out of the carb, spray WD40 into the carb while turning it over. Most people will use after run oil. Give a bit of a shot into the carb and turn the motor over. Doing this will save the motor for some time.