Craftsman 358.791030 Weed Trimmer

The high speed needle is likely the longer of the two. Often they are different sizes and cannot be interchanged.

Hi AVB, when you say longer, my needles have the exact same threads and also seem to be the same length except for the unthreaded part before the needle point itself. How are the needles measured length wise to know which is which.

When I google the 530071811 I came up with it being a simple start C1U-W19.
 
Here is what the mixture needles should look like. I actually remove from the w19 here.

The overall length of the L needle is definitely longer.
 

Thank you so much AVB, that really helped!  I have the C1U-W19 craftsman.  Have a great day!

There is a couple options.

1. Is to remove the front shroud. The front clutch drum has a T20 screw in it which you need a straight torx to get it loose (right threads). You also need a piston stop to remove the clutch. Note this clutch is left hand threaded.
2. Another option and depends if it is your personal trimmer or the customer's. This would be drilling a small hole just large enough to get the torx driver through so you can remove and tighten the screw. It just becomes air vent hole. Personally I disassemble the trimmer if it is the customer's as most are fairly picky about looks. Just takes a little when you got the right tools.

I kinda doubt the muffler is clogged as I have never seen one these trimmers. The ones that I see clogged spark arresters on are the ones with the removable screens. But if the muffler is indeed clogged just replace it. Plenty of scrap trimmers out there so an used muffler should be easy to find. This trimmer is basically a 25cc Weedeater Feather Lite trimmer in disguise. Otherwords in Red instead of Green color.

Yes they were other color schemes. The one you have is an older scheme before Sears decided to go with the red scheme. They just gave them a new model number with a few minor other changes usually slight improvement made by the Weedeater manufacture which is now part of Husqvarna along the Poulan line. So you might even see them in Poulan Yellow when you find the machine with the Poulan label.
 
Btw Sears does not make their own equipment just rebadge other manufacture units and have them dress the Craftsman color schemes. This why when you order parts you might not even get the same color as the you are ordering parts for.