Have a chipper /shedder that refuses to start. Had it for the last 3 years. The first year it ran ok. I have been trying to start it today and have had no luck. Most likely the carb need to be ungummed. most ofthe time to check something like this I take out the plug and add a little gas through the hole to see if it will start. Still no joy. I check for spark and there is spark.The one thing is that it has always been hard to restart when warm. Sometime I have to choke it. what does this mean??

Btw when I take apart the carb what is the reference for the idle mixture screw?? I was told 2 1/2 turns??

Any suggestions??

Instead of going through the whole carb, take the bowl out from under it, remove the jets, and clean everything thoroughly.  Do not adjust anything.  This can be done with standard hand tools, but do not use worn screwdrivers as they will strip the heads of the screws.  Be sure to put everything back how you found it.  I find that this simple repair works over 90% of the time.

is there a drainout for the carb float bowl? you may cant to clear it out and get some carb cleaner in there. also, how fresh is the gas?? the stuff in that fuel line looks NASTY.

I would go with David_Hineline's assement. Those small engines are pretty simple, and I would replace the spark plug. I would also mix recommended amount of carb cleaner & gasoline preservative in with the gas. Air filter clean?

The one thing is that it has always been hard to restart when warm. Sometime I have to choke it. what does this mean??

It means you have to choke it.

Seriously, there are no exact adjustments (2 1/2 turns???).  That may be a good starting point, but you set it where it runs best.  An engine will run far richer than it needs to be, but going on the lean side it will get rough and quit quickly.  So, start rich, lean it out until it runs smoothly, keep going until it starts to slow, miss, back it up rich until it smooths out.  That is where you want to run it.

Adjust the engine under load.

Going too rich it will still run, but will load up the engine, and foul the plug.

Carbs on small engines have not changed since the late 1800's, crude, crude, crude.

The thing probably has trash in it.  Take it off, take it apart, get after it with a can of carb cleaner, put it all back together.  Remove the fuel tank, dump it, flush it out, as well as the fuel lines.  Get all that clean, put in a new plug, and then it should run.

Internal combustion engines need three things to run... air (which is free), fuel, and spark.  If the engine does not run, it is usually a lack of one of these three things.

There is no jet so to speak .
It uses an emultion tube . Remove the bowl
and then the tube and make sure the small holes
in the side of the tube are clean , then reinstall it .

If you've verified spark (I'll assume that is has compression), then prime the carb with a little gas and see if it starts (or at least sputters.)  If it does, then you know you have a fuel delivery problem.  The float/needle valve may be hung-up in the closed position, not allowing fuel into the bowl.

Is there fresh gas in the system?  Water condensed in the fuel tank?

Are the carb screws adjusted to a position that would at least allow the engine to start?

Is the muffler/exhaust system free of obstructions?

One more for replacing the spark plug in any case.  They do go bad even if they look ok.

I thought I had a small Mac. chain saw "go bad".  Two years later, I replaced the spark plug on a whim and it fired right up...gummed up carburetor and all!

I removed the carb and cleaned it out. Plenty of gas in the float.Exchangedthe plug with one from my lawn mower which usesthe same number.Still won't start but my mower started on the first pull.flywheel key??? where is it located at?? front by the pull rope of back by the shedding part???

Thanks

You might find this info useful. I would check compresion before going further. http://repairfaq.ece.drexel.edu/sam/lmfaq.htm

The screw under the float bowl is a mixture adjusting screw, this is an older engine, they have to be very close or it will be either rich or lean. Your problem is that the float bowl is going to be full of gunk, especially if it has been sitting for a while. I do not know how good you are with tools but remove the bowl first then post onwhat it looks like, it'll probably be brown sorta fuzzy gunk all over the place and it will be blocking the "jet" holes. [yeah yeah emulsion tube but no one outside of mechanics or small engine tinkerers will know what the hell it is. they do know what a jet looking thing with little holes in it is. [I'd bet they are plugged partially or all the way]

How good is the spark? Is it a nice and fat blue? If you are pouring gas right into the plug hole and it is still not firing then your spark may not be hot enough(since the plug has been changed and it hasn't helped). Take the cover off of the flywheel, and polish the magneto with a little sandpaper. A tiny bit of rust could be interfering with getting a nice hot spark.

dupe

heres a video and pic of the carb. cleaned it out with carb cleaner and blew out pasaages with air.





[home.comcast.net/~stgfal/mower_005.mov

spark looks good