I have a Stihl multitool. It runs fine for a few minutes, ant then it will not rev. I've cleaned the exhaust screen. Could it be a bad coil?

SOURCE: WILL NOT REV

hi mate it sounds mechanical side instead of electrical have you changed the air filter or cleaned it also check to make sure the oil and petrol are being mixed correctly and check the air screw on the carb is the right amount off turns out if its incorrect it will either be to rich or to lean it normally says the amount of turns in the manual also check to make sure the jets are clear and the reed valve is closing propally many thanks

SOURCE: no power fs66 stihl weedeater

Hi When you cleaned the muffler out did you also clean the carbon out of the port on the cylinder as this can be blocked as well. Also you will have to retune the carby, There should be 2 screws 1 for low speed marked l on the carby body and 1 marked h for high speed to start with they should be set at 1 & 1/2 turns out from closed the low speed you set at an idle and the high speed you set at full throttle. Hope this helps.

SOURCE: Stihl 017 that will not throddle up after getting warmed up.

Isuggest you clean the carburetta does not take much grit or dust to foul up the works

SOURCE: Periodically firing while trying to

Catalytic convertor clogged more than likely.. Muffler shop can test back pressure.

Curtis Sewell

• 7482 Answers
• Posted on Aug 24, 2011

SOURCE: stihl weed eater runs for

Hi
Sounds like you have dirt/debris in your caburetor jets,fuel passages or a diaphgram that is becoming non-flexible.
Check/Clean/Replace your Air Filter, a dirty air filter can make your engine run to rich with fuel.
Note: ALWAYS USE COMPRESSED AIR TO CLEAN YOUR JETS AND PASSAGES, VERY IMPORTANT.
Note:Before you disassemble the carburetor:
Mark each piece with a awl, or some kind of instrument that will make an alignment scratch before you disassemble the carburetor into separate pieces.
That way you will know which way it goes back together when you reassemble it.
Sometimes you can get by with priming the carburetor or by using starting fluid and letting it run a few times like that, and it will flush the gunk out of the jets,but most of the time you will need to rebuild the carburetor.
Be sure to check your fuel tank for water and dirt/debris, if there is water/debris then you need to clean your tank.
Check you fuel line condition after a while they will degrade and need replacment.
Check/Clean/Replace your fuel filter if you have one, normally they are located in the fuel tank of weedeaters.
When you remove your fuel lines from the carburetor be sure to make a drawing to how the lines are connected to the carburetor.
Normally the big line will be the line the fuel filter is connected to inside of the tank.The smaller of the two lines is the return to the fuel tank from the carburetor after it is pumped thru the carburetor by the primer bulb.
Make sure you are using fresh fuel...and oil mix if your using a two cycle weedeater with the oil to the right mixture and not too much oil as it can cause hard starting.
If the trimmer is over a couple of years old, then I recommend that you buy and install a new carburetor repair kit,because the diaphragm will get hard and that will cause it to be hard to crank.
The diaphgram may look good and flexible, but it can be deceiving and not act as a fuel pump as it should because it has become too hard and will cause hard starting,start and run and shut off, etc.
When you clean your carburetor, I recommend that you use a laquer thinner type cleaner to clean and dissolve the laquer build-up in the float and needle jet passages.
Be sure to remove all plastic and rubber parts before using the laquer thinner because it can dissolve the plastic parts and render them unuseable.
Be sure to use COMPRESSED AIR to blow out all the fuel and air passages.The higher air pressure is needed to blow some of the trash/debris from the fuel or air passages.
Be careful when blowing out the passages, because there are sometimes small rubber type seats in the bottom of some of the passages.
Keep in mind that the float (if you have one) for the carburetor must be level when you go to reassemble the carburetor or follow the instructions you get with the carburetor kit, or you could also ask the parts man that you get your kit from.
When you clean your carburetor and remove the jet screws, you will first need to lightly seat the jet screws.
But before you lightly seat the jet screws count the number of turns it takes to seat the jet screws from their original position.
Be sure to mark the turns down on a piece of paper.
That way when you put the jets back in, you know to lightly seat them first and then turn them back out to their original position before you started.
Note:
The little spring inside of the carburetor goes under the float arm.
That is where your fuel inlet needle/float valve is located...on the arm at the end.
Normally there is a small indetion in the carburetor base and a small protrusion on the underneath of the float arm where the spring will be in the right postion for installation.
The spring will set in the indention and you will install the float arm with the needle/float valve and float rod into position over top of the spring,you will push down until it is in position and then you can tighten the screw that holds the float arm assembly in position.
Once you have your carburetor cleaned/rebuilt that should solve your problem.
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