Black spark plug

[muddtree]

I purchased a brand new chainsaw last week and used it for a few days. The brand is called WEMARS.

The manual says use 25:1 fuel mix, but the body of the chainsaw has a sticker that says use 50:1.

I've used over a gallon of fuel in it with the 25:1 ratio and it won't start anymore. I pulled the spark plug and the tip is straight black. I bought a new spark plug and want to make sure I run it correct this time. What did I do wrong and how do I fix this?

Thanks.

 

[Vintage Engine Repairs]

The ground strap isn’t a good indication of tune, it’s a better indication of heat range, though plug tuning, unless you’re way off, doesn’t really offer much info now days with fuels and oils being so varied. The flat portion of the threaded area is where you can get an indication of tune and yours hasn’t got enough time on or it’s too lean. There is nothing wrong with 25:1 of a good oil especially in a Chinese saw,

you can wire wheel that plug and see if it’s the cause of your no start, but it doesn’t look bad enough to me. Your issue is possibly else where.

 

[NSEric]

Did it start with the new plug?
I have a couple chinese saws like the wemars, they all come tuned pretty rich.
If you know how to tune a saw lean it out some.

 

[muddtree]

The ground strap isn’t a good indication of tune, it’s a better indication of heat range, though plug tuning, unless you’re way off, doesn’t really offer much info now days with fuels and oils being so varied. The flat portion of the threaded area is where you can get an indication of tune and yours hasn’t got enough time on or it’s too lean. There is nothing wrong with 25:1 of a good oil especially in a Chinese saw,

you can wire wheel that plug and see if it’s the cause of your no start, but it doesn’t look bad enough to me. Your issue is possibly else where.

The brand on the original plug is Torch. I read not so great things. Could it just be a faulty plug? Also how do I know what fuel mix to use?

 

[NSEric]

Did it come with a spare plug? All my chinese saws came with an extra plug. It's also the same spark plug as most husqvarna and stihl saws if you want a ngk plug for it, look one up for a husky 55 or something like that.
You can run anything from 25:1 to 50:1 mix wise and it will be fine. I run 32 or 40:1 in my chinese saws.

 

[muddtree]

Did it start with the new plug?
I have a couple chinese saws like the wemars, they all come tuned pretty rich.
If you know how to tune a saw lean it out some.

Haven't installed it yet. It's raining crazy right now. I don't know to tune it but can figure that out.

 

[muddtree]

Did it come with a spare plug? All my chinese saws came with an extra plug. It's also the same spark plug as most husqvarna and stihl saws if you want a ngk plug for it, look one up for a husky 55 or something like that.
You can run anything from 25:1 to 50:1 mix wise and it will be fine. I run 32 or 40:1 in my chinese saws.

No spare plug. I got an autolite plug from O'Reilly's to replace it. Thanks for the tip on fuel mixes

 

[ZeroJunk]

Likely takes a Bosch WSR6F or equivalent. I have seen spark plugs not spark that looked perfect. So, who knows.

 

[muddtree]

Likely takes a Bosch WSR6F or equivalent. I have seen spark plugs not spark that looked perfect. So, who knows.

I was looking for a Bosch but they didn't carry that at O'Reilly's

 

[Tomos770]

NGK BPMR7A....

If it is not a fault of a plug.....inspect if screen inside the muffler is plugged...

 

[muddtree]

NGK BPMR7A....

If it is not a fault of a plug.....inspect if screen inside the muffler is plugged...

Roger that. Thanks for the direction

 

[Bob Hedgecutter]

The brand on the original plug is Torch. I read not so great things. Could it just be a faulty plug? Also how do I know what fuel mix to use?

In my own experience when cheaper saws show up here- TORCH spark plugs have a very short lifespan and are best replaced with a Bosch or NGK. Usually that cures a thought to be dead economy model saw.

 

[muddtree]

In my own experience when cheaper saws show up here- TORCH spark plugs have a very short lifespan and are best replaced with a Bosch or NGK. Usually that cures a thought to be dead economy model saw.

I'm thinking the same thing brother. Will report back when I get back to the farm. Socal is flooded right now.

 

[Vintage Engine Repairs]

The brand on the original plug is Torch. I read not so great things. Could it just be a faulty plug? Also how do I know what fuel mix to use?

It’s not often the plug, but torch (although in my experience have been fine) seem to cause the most problems of all the brands. It’s a Chinese product that probably doesn't have the best quality control or materials that other better known, named brands from China may do.

 

[huskihl]

It appears to be tuned quite rich. 25:1 is fine if it’s tuned for it. 40:1 is also fine. But choose one oil and ratio and stick with it. Changes in fuel, oil, and ratio may also require tuning adjustments every time

 

[muddtree]

It appears to be tuned quite rich. 25:1 is fine if it’s tuned for it. 40:1 is also fine. But choose one oil and ratio and stick with it. Changes in fuel, oil, and ratio may also require tuning adjustments every time

Okay, Ive never messed with the tuning before. What is a good fuel ratio for rich tuning?

 

[Vintage Engine Repairs]

Okay, Ive never messed with the tuning before. What is a good fuel ratio for rich tuning?

 

[muddtree]

Just an update for everyone trying to help:

I put in the new spark plug this morning and it fired up first go. I used 50:1 fuel mix this time. It blew smoke for the first minute then cleared up.

 

[stihltech]

The Torch spark plug. First thing to replace when used in any engine that won't start.