Craftsman 25cc Gas Line Trimmer - Page 3 - Answered Questions & Fixed issues

That's good ...most won't start...kill switch wire more then likly fell off or tab it connects to broke off...take outer housing off and look for any loose wires...

Hi I have a craftsman 4 cycle model no. 316.791970 gas trimmer. When I pull on the rode there is little resistance . I took the sparkplug out and put a flash light down the hole and there is a thing that is moving . What should I look next, or do you know what is wrong? Thanks for any help! I've had it only 3 years and already Sears have replace the clutch assy.

I bought a Shakespeare Push-n-Load 3 blade trimmer head at The Home Depot for about 26 dollars and picked up a pack of 12 replacement blades for another 7. Did a whole 3 acres worth of weed whacking and still didn't need to change the blades. I was also powering through some pretty thick bushes with ease. Highly recommended.

The most probable problem is no fuel delivery to the engine.

1. Check/replace the fuel in-tank filter, you should be able to easily blow through it once removed. The primer bulb will sink down and not return quickly if the filter is bad. Fuel will not return to the tank via the return line if the fuel filter doesn't allow fuel to be pulled in.

2. If fuel is returning to the fuel tank when the primer is pushed then your problem is inside the carb.

3. To verify this put a small quantity of gas in the lid of a water bottle (half full). And pour it into the carb throat. Replace the air filter to prevent a backfire from shooting flames out. Try to start the weedwacker. If it runs and then dies the problem is inside the carb.

4. If you are really good at working on things with small parts you can clean out the carb and replace all of the gaskets to solve the problem. If this isn't for you then you should take it to a lawn shop and have them clean the carb and replace the gaskets.

NOTE: Replacing the gaskets is very important because the gaskets get stiff and the fuel pump action of one of the gaskets is reduced or stopped.

Hope this helps, Karl

Hi stamile3Try www.jackssmallengines.com, they will have your parts and you can contact them by phone if you want.Bud

Clean the Carburator, Clean out the Carburator Bowl and Float, Change the Spark Plug

the new plug can be got at your local ace hardware or mower shop. it's good to have a new plug as a spare. how to test is let the plug dry off good and place it back on the spark plug wire, now touch the threads of the plug to the motors metal, pull the motor over and watch for spark in the gap, should be a blue spark. if you can't touch ground with the plug use a socket to extend the ground between the plug and the motor.. do not work around gas = fire THINK ! .. Jay

Could be a faulty kill switch not allowing it to start, sounds like you covered all the things I would check.

Hi ArmandoI believe this is what your looking for.Please take time to rate meBud

Hi sukfish...
What caused the old bulb to crack is time and fuel...
Make sure you are getting spark at the spark plug, to do this:
Remove your spark plug and check to be sure you are getting a bright blue spark at the spark plug.
You do this by grounding the plug on the head of the engine and pulling the crank rope, if you are getting a nice blue spark then:
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 mower or 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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remove the cover from the engine to see the coil remove the small wires from the coil and spin it over if still no spark replace the coil

Most probably it's a dirty carburettor, especially if it was stored away with fuel still in it. The fuel 'varnishes' the carb from the inside, thus not enough fuel getting through. Ideally, just buy some carb cleaner from an autostop and spray away in the carb and leave it for a few minutes. Then try using some fresh fuel.Alternatives are the fuel filter is full of mud or the air cleaner is dirty. Remove the air cleaner and see how it goes - will be a bit noisy but nothing else to worry about.

i think the carburator is directly attached to the air filter

Fuel filter in tank with line going directly to the fuel pump side of the carburetor This is the end of the carb with a solid cover. . This line should have length in it inside the tank where it can flop around and stay on the bottom to collect fuel. The other line in the tank should have one of the little connectors on it and can be right up to where the hole in the tank is to hold it there.. This line should connect to purge/primer bulb on the longer outlet nipple. Another fuel line should run from the metering chamber side of the carb (the end with the hole in the cover) to the purge/primer bulb with the shorter outlet nipple.
The purge bulb "pulls" fresh fuel out of the tank via a vacuum created after depressing the bulb and the fresh fuel flows completely thru the carb and any air or old fuel ahead of it are drawn to the purge bulb which then "pushes" this mixture back to the fuel tank.

The gas take up line is disconnected or is broken. I have the same problem and need to find a diagram to fux it.

The thing to remember is that the primer pulls fuel from the carb into the bulb and dumps back to the tank, it does not push fuel into the carb, connect the fuel line from the tank to the carb connection nearest to the alluminium pump cover held with a single screw, the other one goes to the shorter of the two connections on the back of the primer.

Replace the fuel lines and get a carb rebuild kit. If your mechanically inclided its not to bad to replace the parts. The fuel lines are not very expensive and you can get them from a auto parts store or and outdoor equipment parts dealer. The filter in the tank is a little tricky to get out/in but a long needle nose plyers get it done. Good luck..

Either contact Sears or Google the model number for a service manual.

You might want to Google the model number for a service manual or contact a sears service parts center for help.

If the same fuel is in it try draining and re filling with fresh fuel, if no better to rule out an ignition issue, spray some fuel oil mix straight down the carb throat, if it fires up it is still a fuel issue.