Anybody else experiencing sparkplugs won't stay clean in lawnmowers running E10 pump gas?
- Thread starter FordFETruck
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How many hours are on the Spark Plugs?
I would love to switch back to E0, but it's hard to find in my area and super expensive when you do find it.
Engine runs great and uses maybe 2 ounces of oil per change. Here's another out of an engine I rebuilt about 6 years back, does not smoke at all and burns zero oil and runs fantastic. This plug has maybe 25 hours on it, this one was giving me a random misfire at any RPM lately but started and ran well otherwise. I cleaned it with my sparkplug cleaner, and the random misfire is gone. OK, this one is a vintage Motorcraft A7CLM from the early 80's and the heat range is colder than the more modern J19LM type plugs, could be part of the reason why on that one but still. Same type of gooey buildup.
250 hours on this plug was nothing. The original plug out of this engine lasted 23 years and ran for about 850 or so hours before it was changed, and it was still working. It's become a bit of a game with this engine to see how long the sparkplugs will last, normally I'd have just cleaned it but seeing it sparking through the porcelain when I put it in the tester, nah. I put a Denso W14LMU in it this time. I get the same kind of buildup even on new engines that have ran for a while.
That's about the hottest heat range I can put in it, that I can find anyways.
How old is your fuel, and how do you store it?
I agree. Unless something obviously happens to the plug it's usually a waste of money. I've seen multiple small engine plugs last 500+ hours just fine. I always put a new plug in something I work on for somebody just because you never know and I don't want to hear that it quit working 3 mowings later, but my own stuff meh, only when needed.
I go through about 15 gallons of small engine fuel per year so is usually pretty fresh. Always stored in the garage away from sunlight, always use fuel stabilizer. I do regularly use MMO in the fuel, but I have also NOT used it several years in a row and didn't really notice a difference in how the sparkplugs look. Perhaps that could be part of it? sure does do a good job keeping the carb diaphragms flexible I have found out.
I'll second cold plug not burning off deposits.
Low rpm usage will cause buildup, running on ''turtle'' instead of ''rabbit'' all the time for example.
Does this engine vent the crankcase into the intake? Possible intake oil source also.
Low rpm usage will cause buildup, running on ''turtle'' instead of ''rabbit'' all the time for example.
Does this engine vent the crankcase into the intake? Possible intake oil source also.
I would stop using mmo, and the stabil. Using e-0 for the last fill of the season, I don't use stabil.
Nope. We dont even have a choice in CA. I almost never change the plugs in my lawn equipment and never have an issue like that.
Overfilled oil even by a cup may pump oil mist into the intake. Don't over oil the carb foam filters. Mowers? Gas rinse then foam element, oil it, then squeeze to a golfball size then let it relax and install. Paper elements on larger engines can become restrictive if they get wet. Talking to you with the garden hose!
Not even going to get into the garbage chinese carbs. If you got a good one you be lucky guy
Not even going to get into the garbage chinese carbs. If you got a good one you be lucky guy
These mowers with the exception of one have the oil fill at the sump level, can't really overfill them. That's what I do with the foam filters, wash them in either gas or hot soapy water, dry them. Oil them and then squeeze the excess out in a rag. No chinese carbs are available for these bad boys, the originals are immortal... I have used several china carbs though with good success on newer stuff.Overfilled oil even by a cup may pump oil mist into the intake. Don't over oil the carb foam filters. Mowers? Gas rinse then foam element, oil it, then squeeze to a golfball size then let it relax and install. Paper elements on larger engines can become restrictive if they get wet. Talking to you with the garden hose!
Not even going to get into the garbage chinese carbs. If you got a good one you be lucky guy
Yeah I'm gonna hold off on the MMO for a while to see if it makes a difference. I haven't used stabil in years though, star tron has been giving good results for keeping the fuel fresh, although the Briggs&Stratton fuel stabilizer was the best I ever used can't seem to get it anymore though. Never did have any luck with stabil.
Unfortunately, The J19LM, Autolite 458, NGK B2LM, Denso W9LM/W14LM are about the hottest flathead sparkplugs one can get. These are all hotter than the Autolite A7N/Champion CJ8 these mowers all came new with. I almost never run them full throttle unless needed but they're always at around 2800-3200 RPM anyways for normal mowing, typical mower running RPM. These engines have a PCV in the valve cover that go up to the carburetor. They work well so long as you don't rotate the engine when they're tipped sideways.
How much MMO have you used per a gallon of gas and why do you assume that when you stop using it the plug will clean itself up?
I would suggest to run NGK spark plugs equivalent to what your owner's manual says. You don't need hotter plug. Just by new plugs and don't put oil in your gasoline.
Hotter plugs dissipate more heat from the engine's combustion chamber and their tip don't get too hot to protect the the gasoline of pre-ignition of high performance and turbo engines (which is not your case) and supposedly make the engine run cooler. For NGK those are the plugs with higher number. However, if no modifications are done to the engine, you should run the spark plug mentioned in your owner's manual or its equivalent.
The Champion J19LM equivalent is NGK B2LM. NGK also has B4LM which is hotter than the previous one.
However, your problem is not the spark plug heat range, but that you used to put oil in your gasoline and we don't know how much yet.
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I sometimes use the recommended amount, which if I remember correctly off hand is 4 OZ per 10 gallons, sometimes I use half that amount. For many years I used none at all or just here and there if I had any. I noticed the years I didn't use it I would occasionally have issues with diaphragm carburetors, haven't had any issues with them using it which is the main reason why I use it. BTW, the B4LM is colder than the B2LM. NGK the lower the number, hotter the heat range. I used up my last B2LM on my sisters mower otherwise I would have put one in, have had good luck with those Denso W14LMU's in the past though. Here's a fun one, I remembered sticking the borescope in the cylinder of this mower the last time I checked the sparkplug which was 3 years ago apparently according to the time stamp and found the picture of it, this was 13 years worth of carbon buildup at the time since I had this engine apart for cleaning and inspection back in 2009. I guess if the MMO is the cause for the cruddy plugs that's a small price to pay for the rest of it being so clean and lack of carburetor trouble across the fleet. As far as assuming if I stopped using it that the plugs would clean themselves up, they probably wouldn't unless they were run full throttle all day long or I cleaned them myself to start over.
Here's another one while I'm on a roll I'm sure you all will find amusing. When I took this engine apart back in 09 (the one the spark plug pic is from), the original mower body had pretty much bit the dust, we had the left rear height adjuster held together with zip ties since 1998 since the spring tang broke and the wheels were so worn out you could pull them 45 degrees sideways and it would take a 90 degree corner on all fours the wheels would just lean right on over but the body hadn't even rusted, had I known what I know now and all the bad mowers I've had since then I wouldn't have tossed it. This thing ran for 32 seasons, approximately 1200 hours of use, mowed over a lot of hard objects, mowed a ditch for years, ran over 7 snakes in 1 mowing, twigs, tree branches, hit a large chunk of power wire that was thrown into the grass in the back yard in 2005 that we hit twice, once by me, once by my dad. I have never seen an engine stop turning so fast ever since - hit at full throttle both times and wrapped it up around the blade and it even put a gash in the deck behind the discharge chute, it fired right back up both times it never even phased it. It ran for years with the cooling fins needing cleaned, always had its oil changed twice a year though.
In the early 2000's when we didn't know much better, we ran 5 gallons of stale outboard boat gas through this engine to get rid of the gas. It made a colossal mess on the mower deck; it ran for another 7 or 8 seasons afterward like nothing ever happened- never even checked the spark plug. When I took the head off, the combustion chamber was filled flush with hard carbon to the quench pad, almost 1/8" buildup on the top of the piston, valves barely able to be seen. It was incredible, yet it started and ran perfectly like this like it was never even there. This engine's cylinder didn't even have a ring ridge, beautiful cylinder wall with full crosshatch still present, piston, rings all fine. I took the rings off the piston and checked the ring gap it was still at factory spec, Crank, rod and main bearings/journals all still looked new with no wear. I cleaned that sucker up and put it back together and bought a $10 MTD mower that was similar enough and ran it on there ever since problem free because every other mower we ever had new or second hand wound up being troublesome right off the bat. It wasn't until april of this year after 15 years of searching I found another identical model lawn chief like we had, restored it and put this engine on there. It's still running like new all these years later. It's only had 3 replacement spark plugs now, 2 sets of points, 1 carburetor rebuild, 1 air filter foam, still has the original starter rope. That carb also ran for 32 years before it ever was taken apart, sat under the house every winter with gas in it, usually starting first pull in the spring. The carb base warped, and the diaphragm wouldn't seal anymore the choke wasn't working properly and it ran poorly. I resurfaced the carb with a flat surface and piece of sandpaper, put a rebuild kit in it and haven't touched it since. That carb was so packed full of dirt it was insane, ran perfect until the diaphragm wouldn't seal anymore. I'm sure some of y'all will find this one amusing, it's been a hell of a trip with this thing.
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