Stihl sparkplug BPMR 7A or BPM7A

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Being a service tech for Husqvarna BPMR7A is what we put in all the saws. NGK is what we use for any of the equipment actually. I won't use anything else. If a machine comes in with a Bosch or Champion plug its leaving with a new shiny NGK guaranteed. I have a few Sachs-Dolmar saws and the one 116 i'm working on had the BPM7A plug in it but i'm going to put in a BPMR7A because thats what i've got on the shelf haha
 
Im in the same boat with angry hippo, I put ngk in everything .. lawn mowers, chainsaws, generators, weedeaters, trucks, cars, boats etc because they work and keep working and are not made in china. I tend to order several at a time by putting the model# in the search window on rock auto parts dot com because they have the best prices but in a pinch the local auto parts places carry them if you look around.
I have had too many problems with using bosh, I wont even buy them and if I find them in use recommend their removal. Autolite and champion are ok but I have experienced them new but internally failed. I have removed lots of the E3 plugs from cars/trucks that were failed, the electrode arms were eaten off or the ecm rejects them same with the old splitfires but I have 0 experience with them in small engines.
 
Put the non resistor plugs in saws with magneto ignitions and put the resistor plugs in the electronic ignition saws.The mag saws need as little resistance in the secondary circuit as possible.I have many many pieces of small 2 stroke equipment and 4 stroke equipment I have been cleaning and reusing the same plugs for many years .Was a logging contractor and a resort operator I never found defective spark plugs to be an issue if they were from the major players.I can only remember a couple of defective brand new plugs both were NGK.
Does any one remember the old spark plugs you could unscrew the nut and take them apart to clean them you could also silver solder on the center electrode wire.I have the original Champion spark plugs in my dads 1924 2.5 hp Evinrude Sportwin outboard motor.The old girl runs like a charm even though its not Stratto or what ever the latest BS gimmick craze is in fashion only to fade away to a new selling gimmick.
Kash
 
Run what the manufacturer specifies...
Radio interference aside, running a resistive plug on a system that was designed for a non-resistive plug will cause excess voltage which may damage coil circuit components or break through the internal insulation.
Running a non-resistive plug where a resistive plug is called for will cause a higher current to flow at a lower voltage, giving a less intense spark & creating more heat that may damage coil windings or circuit components
 
From Gas Engine Magazine.....

Gadget plugs are among the favorites of many collectors. As I stated at the start of the article, everyone had a better design for spark plugs and in this section we see some of the more, well let’s say interesting ideas. The ZWP & ‘The One Point’ both had long adjustable electrodes so the plug would fire off the top of the piston. The Multi Point, Multiple Point and Fan Flame all had little fans on the bottom to blow carbon off the plugs. The Barney Google had a little breather on the side of it. The Blue Ribbon had a big breather on its side, the Movie Plug and the Schlecht Sliding Gap both had little propellers sliding up and down the electrode, the Duraball, Yale Ball Point, Fouless Non Oyle, and Mulkeys all had little balls that rattled around loose in the plug to keep carbon from forming. Then there were those that had the ball mounted solid to the end of the electrode with the idea that the spark would jump from various points on it thus making it foul proof. Plugs using this idea were TAD Flash Ball, the Ball, and Milwaukee Flash Ball, Taco and the Ball Arc. There are more gadget plugs than we have talked about here, some with ceramic balls, some with valves and even some with whistles, but this gives a little insight to those trying to cash in on the spark plug bonanza.
 
There were many wonder plugs marketed over the years and some wild claims as to there effectiveness.I do not have my plugs handy as they are 70 miles away but mine were 7/8 pipe thread made by Champion I think they quit making them as the plugs would last foreever with a little maintanance.They got rid of fuel pump rebuild kits the same way they made the fastners so you could not take them apart with the lame excuse that the cost of a new pump was so low why bother to rebuild.It is like my Dodge van no dip stick to check the transmission oil
they must have come up with some miracle metal and guaranteed never to leak gaskets or a miracle oil that always stays in the tranny.I also have Champion threaded nut plugs in 18mm.
Kash
 
KASH... I know all about the no dipstick crap in Dodge/Chrysler vans! LOL My aunt and uncle have had them vans since the first ones came out. Even my aunt's daughter has 2012 van now with the dreaded 3.6L Pentastar!

Tranny hose seepage/leakage caused trans loss of prime code. Found the tube, but no dipstick! Now here is the kicker... ya gotta buy a special tool/dipstick to check the fluid level at a certain trans fluid temperature! AYFKM! Then look at a chart to determine if it's low or not.....

https://www.dormanproducts.com/p-52514-917-327.aspx

Sorry for the de-rail.
 
Manufacturers started removing under hood transmission dipsticks and using in line cooler thermostats shortly after the "flush" machines were introduced because it was causing trash from the coolers to dislodge ruining transmissions under warranty. Plus they added the "Lifetime" fluid disclaimers to help prevent jimbob from putting the 3.99 a quart dex III into a units that require expensive VI, 5+, CVT, etc specific fluids that are full of solenoid controlled valves and require special anti sling or foaming additives. Even some differentials now require very specific fluids or they will whine/chatter and cause bearing failure and Its not just a friction modifier. Its the difference of using the correct specific weight in synthetic vs non synthetic.
 
The problem with "Lifetime" fluid (& a lot of other "non-service" components) is it's only fit for purpose for the lifetime the manufacturer wants the product to have... Which doesn't tend to be much longer than the warranty period. Often the inability to service is specifically how they limit the life expectancy of a product. Good for sales, bad for the planet. Ironically EV's are at the pinnacle of this practice
 
Manufacturers started removing under hood transmission dipsticks and using in line cooler thermostats shortly after the "flush" machines were introduced because it was causing trash from the coolers to dislodge ruining transmissions under warranty. Plus they added the "Lifetime" fluid disclaimers to help prevent jimbob from putting the 3.99 a quart dex III into a units that require expensive VI, 5+, CVT, etc specific fluids that are full of solenoid controlled valves and require special anti sling or foaming additives. Even some differentials now require very specific fluids or they will whine/chatter and cause bearing failure and Its not just a friction modifier. Its the difference of using the correct specific weight in synthetic vs non synthetic.
I lay some of the blame on the vehicle owner for not knowing/researching the car/truck they bought/have. My G@D... ppl have an entire world of info in their hands, (smart phones), and some or most never think to use it. I also lay blame on the EPA and manufactures for inventing this crap. Fluids as thin as water or worse to "Gain MPG with less emissions". .. One year oil changes... (yeah, right!)... owners manuals/dealerships that state it perfectly ok to BURN 1 qt of oil between oil changes.. right out the tail pipe... displacement on demand and variable valve timing destroying engines before 100k miles= no thanks, I bought a V8 and gonna use all 8 cylinders all the time so EFI Live to shut it off. BTW... I lost 1MPG after that... I can live with that if it means saving my engine from self destruction.

Again.. sorry for the de-rail and a bit of a rant... and no offense to you cookies.


And now this.....
 

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I've run into the same quandary. Ordering up pile of maintenance and spares at an online supplier. Looked up a specific Echo model to nail down THE part #, and the NGK situation leaves me with resistor -AND- non resistor versions in the "choose from" column.
So, the magneto vs. solid-state argument just -ISN'T- holding true, What is one to do ?
 
C
I've run into the same quandary. Ordering up pile of maintenance and spares at an online supplier. Looked up a specific Echo model to nail down THE part #, and the NGK situation leaves me with resistor -AND- non resistor versions in the "choose from" column.
So, the magneto vs. solid-state argument just -ISN'T- holding true, What is one to do ?
Check an ipl or owners manual for the saw
 
I seem to remember that back in the day the Stihl rep told us at the shop to use the resistor spark plugs. For some reason they were necessary for the ignition system to work correctly. My owner's manuals only list resistor spark plugs, so there is something to the tip from the rep. All my equipment gets NGK.
 
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