What spark plug?

[Oldtom]

I have an old Weedeater mower with 3.75 HP Briggs. The mower is older and has seen hard use, along with maintenance by Bubba J. Vicegrip. The current spark plug is a Champion J19LM. I cannot confirm this is the correct plug online.

I have posted engine numbers below. Is there a good " generic " plug for the 3.75 Briggs? Thanks in advance for any advice

 

[Propflux01]

Champion CJ8, RCJ8, RJ19HX, J19LM, and RJ19LM were used in this engine. .030" gap. Your engine has the correct plug installed.

 

[slacktide_bitog]

Use NGK BR2-LM or Autolite XST458

NGK is the best, but the Autolite is iridium, the only iridium I know of in that size.

 

[Kestas]

Should an iridium tipped plug even be considered? They are designed to minimize wear at the electrodes. I doubt this is a problem with lawnmowers. The plug would probably foul before it experiences any wear.

 

[JayhawkRoy]

I never had any issues using Champion RJ19LM plugs. I think they run about $3.19 at O'Reilly Auto Parts.

 

[skyactiv]

I would replace it with the same plug currently on the mower. Looks like it lasted awhile, no need to overthink it.

 

[jhellwig]

Clean it gap it and reuse it if the electrode is relatively square. Plugs get over changed on small equipment. You will know when it needs replaced.

 

[Propflux01]

That plug will probably outlast the engine anyhow.

 

[slacktide_bitog]

Should an iridium tipped plug even be considered? They are designed to minimize wear at the electrodes. I doubt this is a problem with lawnmowers. The plug would probably foul before it experiences any wear.

The iridium plug has a finer electrode and requires less voltage and should be easier to start. You will likely get better gas mileage as well.

When I had one of those flatheads, I considered the Autolite iridium but ended up using the NGK instead. It started in one pull, which it never did with the original Champion loser

If I ever have another Briggs flathead, I'd try the Autolite iridium.

 

[Oldtom]

Awesome ! Thanks to everyone who replied.

 

[Fishinfool58]

Can anyone help me determine what spark plug I need for a B&S 140 cc 550ex lawn mower engine? There is an Autolite in there now, but those are hard to find in my area. What would be the Champion equivalent? Thank you!

 

[Astro_Guy]

Can anyone help me determine what spark plug I need for a B&S 140 cc 550ex lawn mower engine? There is an Autolite in there now, but those are hard to find in my area. What would be the Champion equivalent? Thank you!

I believe it takes a Champion RC12YC which cross references to NGK BCPR5ES (copper) or NGK BCPR5EIX (iridium.) Lowe's stocks https://www.lowes.com/pd/CHAMPION-71ECO-QC12YCX-RC12YC-5-8-in-Small-Engine-Spark-Plug/1000763422 if you care to stay with Champion but up the game to a fine wire design.

 

[Fishinfool58]

I believe it takes a Champion RC12YC which cross references to NGK BCPR5ES (copper) or NGK BCPR5EIX (iridium.) Lowe's stocks https://www.lowes.com/pd/CHAMPION-71ECO-QC12YCX-RC12YC-5-8-in-Small-Engine-Spark-Plug/1000763422 if you care to stay with Champion but up the game to a fine wire design.

Thank you! I put that plug in but still having same issue with mower starting but only running for a few seconds before it dies. Warmer it gets the shorter time it stays running. Appears I have a bigger issue

 

[Lubener]

Can anyone help me determine what spark plug I need for a B&S 140 cc 550ex lawn mower engine? There is an Autolite in there now, but those are hard to find in my area. What would be the Champion equivalent? Thank you!

I have used J19's in those engines.

 

[Lubener]

Thank you! I put that plug in but still having same issue with mower starting but only running for a few seconds before it dies. Warmer it gets the shorter time it stays running. Appears I have a bigger issue

Magneto could be breaking down.

 

[Lawnman23]

Should an iridium tipped plug even be considered? They are designed to minimize wear at the electrodes. I doubt this is a problem with lawnmowers. The plug would probably foul before it experiences any wear.

I've switched all my OPE and other spare small engines over to iridium plugs, either NGK IX or Autolite XST.

They all start easier/faster and get better fuel economy. Its a no brainer for me, I wont ever buy copper again.