Help with Stihl FS 45 trimmer

[Boots]

So the answer is that the 4140 400 1308 will work for the 4140 400 1303a??? I am having the same problem, the saw shop sold me a 4140 400 1300b and it just backfires. And they won't take it back, they swear it is the correct one and that there is something else wrong with my trimmer. I check the compression witch is at 130#, keyway is good, muffler is good, this machine only has about 20 hours on it. I went to use it the other day and it fired then died. I bench tested the coil and it had no readings.

 

[Fish]

So the answer is that the 4140 400 1308 will work for the 4140 400 1303a??? I am having the same problem, the saw shop sold me a 4140 400 1300b and it just backfires. And they won't take it back, they swear it is the correct one and that there is something else wrong with my trimmer. I check the compression witch is at 130#, keyway is good, muffler is good, this machine only has about 20 hours on it. I went to use it the other day and it fired then died. I bench tested the coil and it had no readings.

Did you just test for spark?

 

[Boots]

Did you just test for spark?

I bench tested it both ways and nothing showed on my multi witch is very weird, the new coil I [1300] got showed readings on my multi meter but it's the wrong coil, the timing is off, it just backfires. I'm trying to find out if the 1308 coil will work in place of the original 1303 so I don't waste another 40 bucks because they won't take them back. Stihl says they have a replacement but I can't read all the serial, just the last 7 digits so they can't help me because its missing the first four. I really don't want to throw this thing in the trash cause its barley used, not even faded, no crud on the spark screen, hardly any scratches on the trimmer head guard, less than 20 hours on it. It sat in the box for years, then I assembled it and used it this year and now the coil blew but can't find one that works.

Edit: I figured out the beginning four numbers witch are 4140 go figure, so with that, stihl says the 1308 will work so I ordered it and will report back if it works. My serial is 4140-311-2301, or is the serial the number under the bar code, witch is 263629942? Then in the top right corner of sticker it says 000 1142. I'm so confused.

 

[Boots]

This is a reply from Stihl USA,

We are in receipt of and thank you for your email. The serial number of your machine is 263629942. Thank you for providing this as this is needed to get you the proper part. The coil part number you need is 4140 400 1308.


Thank you again for contacting STIHL.


Best regards,

Trey Vickery

Technical Service Representative

STIHL Inc.


The serial number is the one below the barcode, some of these STIHL Dealers shouldn't be Still dealers, they are terrible with revisions. I guess you have to go to the source to get the correct info. Thanks for all the help and I'll update when I get the part.

 

[Boots]

Well I got the correct coil [4140 1308] as per stihl, it stumbled on the second pull then won't start at all, so off to the garbage heap for this thing. such a shame I can't get the correct coil, this weed wacker is brand new, just old stock.

 

[Fish]

Take a quick look and rotate the flywheel to tdc, then see where the magnets are in relation to the coil.
I did have one new block that the keyway and crank position were way off.

 

[Fish]

Here is a bulletin that may be useful...

 

[Boots]

Take a quick look and rotate the flywheel to tdc, then see where the magnets are in relation to the coil.
I did have one new block that the keyway and crank position were way off.

Isn't the keyway directly in the middle of the magnets? What is boggling me is that it was running perfect till the coil blew, now I can't get it to fire with the replacement coil that stihl USA recommends per my sn, it won't even fire with fuel in the plug hole. If the flywheel slipped, shouldn't I be able to feel it wiggle or turn it on the crankshaft while holding the crankshaft?

 

[Fish]

Look at the one bulletin, and see if they give you the correct coil. Put up your unit's serial numbers too.

 

[Boots]

Look at the one bulletin, and see if they give you the correct coil. Put up your unit's serial numbers too.

Stihl gave me a 4140 400 1308 coil and said that was the replacement for the original 4140 400 1303, everything on the right side in that bulletin is what my machine has. When the piston is tdc, the magnets are half past the coil. I'll upload a pic. My sn are 263629942.

 

[Wonkydonkey]

Iirc, page 5 in The bulletin. Shows the change in the key way position. You could work out just by looking at your key way, as to which you have.

One other silly question first,, you have set the correct gap on the coil.

Now if the trimmer is heading for the dumpster, I’d file the key off the flywheel and rotate it till I found the correct position. Find tdc. Then fit the flywheel near the coil, maybe move it just a little as if it had fired, or to put it another way if the piston was a few degrees before top dead centre the mags aare alined with the coil.

Edit I was typing when you last replied...!

 

[Wonkydonkey]

The flywheel rotation is to the left, ? the mags are not at the coil yet ?

 

[Boots]

Iirc, page 5 in The bulletin. Shows the change in the key way position. You could work out just by looking at your key way, as to which you have.

One other silly question first,, you have set the correct gap on the coil.

Now if the trimmer is heading for the dumpster, I’d file the key off the flywheel and rotate it till I found the correct position. Find tdc. Then fit the flywheel near the coil, maybe move it just a little as if it had fired, or to put it another way if the piston was a few degrees before top dead centre the mags aare alined with the coil.

Edit I was typing when you last replied...!

Yes the air gap is good and its making bright blue/white spark. Its gotta be the timing, stihl must have discoed the correct coil for this thing. I've tried the 1300 coil witch just backfired, I've tried the 1305 witch did nothing and now I have the 1308 that stihl says is the correct one but get nothing. I'll try and play with the flywheel and see if I can do something with it, would really hate to 86 this thing.

 

[Boots]

The flywheel rotation is to the left, ? the mags are not at the coil yet ?

Flywheel rotation is clockwise and the mags are half past as in pic.

Edit; You are correct, the flywheel does turn counter clockwise, I was looking at the crank.

 

[Wonkydonkey]

i'm not arguing but I’ve just checked my blower bg56 and the hs45 hedge trimmer and the rotation is to the left (anti-clockwise)

 

[Boots]

i'm not arguing but I’ve just checked my blower bg56 and the hs45 hedge trimmer and the rotation is to the left (anti-clockwise)

You are correct, I was wrong, I was looking from the crank side, my appologies.

 

[Wonkydonkey]

No problem

 

[Boots]

So the timing should be on point then right? I don't know what else it could be.

Maybe I'll put it all back together and play dumb and sell it in the spring stating that I just took it out of storage and it won't start lol. Just joking, I'm not that dude, but know plenty of them.

 

[GBertolet]

I am the O.P. of this thread. My info tells me that the 1308 coil is incompatible with any FS45 made after 2001. There is sometimes erroneous or incomplete information out there. I was originally told that the 1308 coil was the correct one for my pre 2002 FS 45. I even purchased a 1308 coil, when I was told it was the correct one. My trimmer, like yours fired out of sequence, with the 1308 coil. The original coil was a 1303A, and that was what I had to purchase. It started right up with that coil. It was very difficult to find one, as they are discontinued, but I located a used one on Ebay, for under $10.

 

[Boots]

I am the O.P. of this thread. My info tells me that the 1308 coil is incompatible with any FS45 made after 2001. There is sometimes erroneous or incomplete information out there. I was originally told that the 1308 coil was the correct one for my pre 2002 FS 45. I even purchased a 1308 coil, when I was told it was the correct one. My trimmer, like yours fired out of sequence, with the 1308 coil. The original coil was a 1303A, and that was what I had to purchase. It started right up with that coil. It was very difficult to find one, as they are discontinued, but I located a used one on Ebay, for under $10.

Yes, that is the issue I believe, I've been looking for a 1303 but they are nowhere to be found. You probably got the last one lol.