Spark Plug Error Causes Saw to Run Lean?!?

[happysaws]

Okay...so I have an old Remington chainsaw that was running lean when cutting, even with the high idle screw set 3+ full turns out.

I ruled out the following;
*carburetor
*fuel pickup
*fuel lines
*air filter
*points (gap)
*coil/condenser/flywheel magnets
*condition of p/c
etc...

The saw would start in 3-4 pulls, idle like a champ, rev up great and make 4-5 strong cuts. After the 6th or so cuts (in about a 8in. log) the saw would begin running lean and eventually stall and shut off.
It would then be VERY difficult to restart.

After running out of ideas as to what to try next, I finally exchanged the old Champion J6J spark plug for a brand new CJ6. The old plug put out consistant, hot blue spark, I had no reason to think that the plug was bad.
After a new plug, the saw cuts great, never runs lean (even when hot), and always starts on the 1st pull when warm.

I did not touch the carburetor settings or anything else when I changed the spark plug.

So.... My question is; why would a faulty spark plug cause the saw to run lean? Or what could have happened to the spark plug to cause it to make the saw run lean and stall?

Any input is greatly appreciated!![emoji4]

 

[jr27236]

I don't think spark (heat range)would have anything to do with leaning out. I would say it was cracked on the porcelain and that crack would expand when it warmed up letting air in or just a bad crimping seal on the plug, doing the same. Also as for the stalling the spark grounds out through the same crack and shuts the engine down. Put that plug back in and run in the dark (lol so dangerous, without bar and chain) and you'll possibly see the spark jumping to the cylinder.

 

[grizz55chev]

I don't think spark (heat range)would have anything to do with leaning out. I would say it was cracked on the porcelain and that crack would expand when it warmed up letting air in or just a bad crimping seal on the plug, doing the same. Also as for the stalling the spark grounds out through the same crack and shuts the engine down. Put that plug back in and run in the dark (lol so dangerous) and you'll possibly see the spark jumping to the cylinder.

Check your fuel tank vent, if it's plugged and not functioning right you'll experience these symptoms.

 

[jr27236]

But hes saying it cleared up upon plug change?

 

[mohick]

Yeah yeah and B S walks too!!!

 

[happysaws]

Check your fuel tank vent, if it's plugged and not functioning right you'll experience these symptoms.

I also ruled out the fuel tank vent, forgot to put it on the list.

 

[happysaws]

Yeah yeah and B S walks too!!!

Huh? I am not trying to start anything.

Only wanted to know why the plug made the saw run lean.

 

[beavis331]

I work on a lot of antique engines for a livings. Sparkplugs can do funny things. Your plug was acting up. It did not make your carb go lean or you would have scored a cylinder. I have seen a lot of carb\fuel issues solved by an ignition change! Sometimes diagnosis can be tricky. Don't be afraid to try new plugs when all else fails! I have seen it solve what seemed to be fuel issues.

 

[happysaws]

.....Put that plug back in and run in the dark (lol so dangerous, without bar and chain) and you'll possibly see the spark jumping to the cylinder.

I'll give this a try.

 

[happysaws]

I work on a lot of antique engines for a livings. Sparkplugs can do funny things. Your plug was acting up. It did not make your carb go lean or you would have scored a cylinder. I have seen a lot of carb\fuel issues solved by an ignition change! Sometimes diagnosis can be tricky. Don't be afraid to try new plugs when all else fails! I have seen it solve what seemed to be fuel issues.

Okay thanks for the help.

 

[beavis331]

I have had sparkplugs give nice blue spark but still act up in the hole. New plug solved the issue. Even had it happen in chainsaws. One of the reasons I don't like to run champion plugs is because I have been burnt a few times on issues like these.

 

[happysaws]

I have had sparkplugs give nice blue spark but still act up in the hole. New plug solved the issue. Even had it happen in chainsaws. One of the reasons I don't like to run champion plugs is because I have been burnt a few times on issues like these.

I agree, I try to avoid Champion plugs at all costs, the only reason I am using them is because I have a bunch that are all NOS.
I've had great luck with E3 plugs.

 

[beavis331]

Most of the time champion plugs are ok but every once in a while I will have trouble with them. Mostly use autolite myself. I've talked to a lot of old auto and tractor mechanics that say a lot of your carb issues are solved by an ignition tune up!

 

[jr27236]

Yeah yeah and B S walks too!!!

What does that mean?? Unfortunately with text we cant tell if you are joking or being an as$ so many take the later of the two. Better to clarify

 

[happysaws]

Most of the time champion plugs are ok but every once in a while I will have trouble with them. Mostly use autolite myself. I've talked to a lot of old auto and tractor mechanics that say a lot of your carb issues are solved by an ignition tune up!

Agreed,
I've had brand new Champion plugs that didn't produce any spark, or the porcelain was cracked in half.

I should have tried a new plug before anything else.

 

[alexcagle]

I agree, I try to avoid Champion plugs at all costs, the only reason I am using them is because I have a bunch that are all NOS.
I've had great luck with E3 plugs.

Those E3 plugs are death to quickie saws for some reason.
Every E3 plug I have removed out of a cutoff saw had a roached-out piston and cylinder. I am wondering if maybe they run hot.
But then again, they may have killed the saw, then tried a new fangled fancy spark plug, hoping for a holy miracle....lol

 

[smokey7]

I have had bad plugs new out of the box of every brand. Also have had similar failures of all brands with ground straps breaking off and damaging stuff before they get out. E3 plugs have been especially bad for me also. Spark plugs have a tough job to do but aside from the straps breaking off i cant say for sure they can cause a 2t top end to melt down. It does seem to me that the plugs are kindof universal. If you look at the cross referance chart for several different heat ranges they all come back to the same E3 plug.

 

[axeandwedge]

Just because you have a head like a spark plug It doesn't make you a champion lol.

Sent from my H8216 using Tapatalk

 

[HarleyT]

I would guess that the j6j plug was not fully threaded in and leaking, as the reach is way longer than the cj6 plug.

 

[HarleyT]

Well, just found a pic of an old one, a little bit longer...