My new leaf blower died after 10 minutes of use and I took it to the warranty service place. They found the spark plug was blackened and fouled and would not ignite the fuel. They replaced it, and now it seems to work OK.
What would cause a spark plug to foul and therefore fail with so little usage?
It is a 2 stroke engine, a Husqvarna. I have another Husqvarna 2 stroke leaf blower several years old with probably 100 hours use, and it has never needed any service. I use the same fuel in each. I get that 2 stroke fuel is oily, and I guess it might foul plugs faster than 4 stroke, but that doesn’t explain a difference between two similar 2 stroke engines running the same fuel. I mean, we’re talking a 600 X lifetime difference, even if the older one fails tomorrow.
Did you follow Mfgr reco. fuel mix for new engine? Newer engines use very little oil compared to older 2 strokes-- yours seems to want 50:1.
Did you leave the choke on?
Perhaps plug gap was wrong on new blower, or faulty from new. Its not something people normally check out of the box, but can happen.
I wondered about this. I figured it was unlikely because a return that looked new probably wouldn’t have enough hours on it to foul the plug.
I was using the same can of 50:1 mix that I use for the old one.
Choke was off, other than to start it.
Hadn’t thought of this one. You think it could be running rich enough to foul the plug this fast, and still seem to perform well?
This is a worrisome possibility. I’m not sure how old the gas is. Now wondering if I should toss what gas I have on hand.
I did also just buy premixed fuel. The new blower has a gas tank that might be a cup in capacity, maybe. I bought several containers that were I think a liter, for about $8 each. This is an outrageous $24 per gallon, and yet a perfectly acceptable price given how little fuel these use in a year. Since I’m not sure what to change, but suspect something is wrong, I thought I’d try this. For many years I’ve been mixing the fuel myself and this is the first time anything seemed problematic.
The canned gas is stabilized and should be good for at least a year in the can–not necessarily in the tank of the blower, however. E10 from the pump is not recommended for small 2 strokes, and if it is used, don’t store it for long, especially in the machine. So, concur–bad fuel, bad plug, poor electrical connection to the plug, some anomaly… There’s not a ton of adjustability on those little carbs, so unless you’re at altitude, it’s probably not that.
Perhaps it was run at the store to demonstrate, or something, with an excessively high oil mixture? It should be ovbious though if it had been previously used becuse the gas tank will smell like gas and likely have some residue. I assume oil does not settle in casoline (to create an excessive oil mixture at the bottom of the tank), I’ve never heard of anything like that.
I had a Yamaha 100 Enduro and later, a Yamaha 250 Enduro, when I was a kid. Both of them fouled plugs until we figured out which different (hotter?) spark plug to use. I always carried a new plug in the bikes’ tool boxes.
Silly question that I should know, but… What makes a hotter spark plug? Bigger/smaller gap? That may be the culprit too if changing plugs was the solution for Napier’s blower…
I think it’s the length (of the threaded part?). ETA: See ETA 2.
ETA: So you have to select a grade of spark plug that will fulfill these requirements. If the engine is being worked very hard or is a high performance engine then a plug will have to be selected that is at the cool end of the range as it will be able to conduct away a lot of heat. Conversely, if you have an engine that does not have to work hard or is a low performance engine (a motor mower engine might be a good example), then the plug required could be selected from the hotter end of the range as there will be less heat being generated by the engine; so the plug must retain more of the available heat.’
ETA 2: ‘The major structural difference affecting the heat rating is the length of the insulator nose. A hot-type spark plug has a longer insulator nose. The insulator nose of a hotter spark plug has a longer distance between the firing tip of the insulator and the point where insulator meets the metal shell. Therefore, the path for the dissipation of heat from the insulator nose to the cylinder head is longer and the firing end stays hotter. The insulator nose of a hotter spark plug also has a greater surface area that is exposed to more of the ignited gases and is easily heated to higher temperatures. A colder spark plug functions in an opposite manner.’