Weekend Freedom Machines banner

What's your favorite spark plug for the Onan 18hp ?

16K views 20 replies 14 participants last post by  dave24319 
#1 ·
About to tune up my winter 318 and I thought I would ask just to get a random opinion then go from that. Thanks in advance !
 
#3 ·
plugs are like oil IMO

I have used champion and NGK in most everything with out issue

our van has orig plugs in it and has 200k miles on it. My truck has 102k miles on orig plugs
 
#6 ·
I have not changed the plugs in my 420 since owning it in 2004. it also sat for 7 years.
 
#7 ·
Thanks all. I'll go with the majority. I feel the need to replace mine and even at $ 14 , it's a bargain to me.
I guess I look at things differently than others. $14 once will not get my driveway cleared from snow. $14 put into my trusty 318 will get a cleared driveway as many times as it takes all winter long. I don't factor in stuff like spending more for the part I need.
Thank you for taking the time to reply
 
#10 ·
You do NOT need anything but the standard NGK plug. There is zero benefit to running a different metal electrode plug, as these ignitions dont put out enough juice to make them worthwhile.
BTW, the dealer charges about twice what everyone else does.
Champion RS14YC Traditional
NGK TR5 2238 V-Power
Denso T16EPR-U 5022 Traditional
Bosch HR9DC+ 7879 Bosch Super
Autolite 104 104 Traditional
 
#15 ·
The NGK part number for Iridium TR5 plugs, NGK 7243 TR5-1 IX

I have not used a Champion for years, maybe since they moved production to Mexico. It was at one time, the only plug I would consider using.

Must be a reason that most of the car and truck mfg are using Iridium and Platinum tipped plugs in the new 100,000 mile tune up interval vehicles.
 
#17 ·
Bill the Iridiums are a good choice and are practically maintenance free as the exotic metal tips are so highly resistant to electrical discharge erosion, with the benefit of a fine wire electrode that will practically never foul even in incorrect mixtures and oil burning engines and also fire better with marginal power ignitions than the old iron plugs that were around when the Onans were the latest and greatest,
 
#20 ·
I have 2 1992 chevy luminas and one has iridium plugs and the other conventional copper plugs and the difference in startup and engine pickup on acceleration is as different as night and day between the two.
The iridium plugs make the engine drive like a new engine. And the car accelerates acrually too much for my old back.
May be worth trying in the Onan for when that 49 thrower takes a big bite in the heavy snow.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top