Just to start. here is the parts list for you unit.
The engine is a 4 horsepower Tecumseh L-head engine.
The serial number tells me the year it was made, but it DOES NOT tell me the Decade. SO if you can guess the decade, I can tell you what year it is.
IT was made in either 1971 or 1981 or 1991 or 2001
It was made on the 199th day of that year.
The engine is NO longer available and the Tecumseh company that built the engine is our of business (2 years ago)
Engines MIGHT be available to replace this, but it would have to be inspected by a GOOD mower repair shop to find out which one would replace it. They have a very special crankshaft that is usually only used on chipper shredders. You would have to get a Briggs & Stratton engine if you want to change. But it will not be easy to find out what engine will fit.
You might be able to get the information for small engine warehouse. http://www.smallenginewarehouse.com/ You will probably have to contact them by phone and let them know what you are wanting to do.
CArburetor repair parts are usually available from any good mower shop. Make sure you get the correct gaskets so it will work properly.
Other parts are also available from many dealers but sometimes will be harder to find.
The problem with the carburetor is most likely that you have dirt or gum or varnish in the small passages...some of which you cannot see or get to in order to clean them.
You should use a good carburetor cleaner available at most good autoparts stores. NOT GUMOUT.....that is almost like using water. Get a GOOD cleaner..
I kind of doubt that the magneto is the problem. If you have spark, it is probably ok.
Here is my comprehensive carburetor and fuel answer that may give you some ideas.
As engines sit or get older, fuel that is left in the carburetor can turn to gum and varnish and cause this and other problems. Also, any gasoline that was left in a gas can for a period of more than 30 days must be discarded because it also has begun to turn to varnish.
Today's gasoline's contain MTBE and alcohol. (Ethanol) They turn to "Junk and garbage" very quickly. Alcohol is partially water (H2O). And they call it "Oxygenated fuels! It is the oxygen that breaks down the organic compounds in the fuel and turns the gas to "Garbage" (Gum and varnish) The fuels we had just a few years ago had no alcohol in it and would store for longer periods of time before going stale... and fuel stabilizers do almost nothing to prevent the fuel from going bad with the changes in today's fuels.
Do not buy gas from the "Discount" Stations. The discount stations get a reduced price on gas because they may be buying fuel that is nearly 30 days old already. You may be getting fuel that's nearly stale right from the pump when buying from a discount station. Purchase your fuel from the well-known stations such as Shell, BP, Sonoco, Phillips 66 etc.
More than 70% of all of our repairs in our lawn mower business are due to this same issue. You most likely have dirt, gum, varnish...etc in your carburetor plugging up the small passageways and jets in the carburetor.
The carburetor must be removed from the engine. Clean all parts with carburetor cleaner and blow out all the small holes and passageways with compressed air. Remove all of the non-metallic parts since the carburetor cleaner will cause them to be disfigured decompose and plug the carburetor as time goes on.
Wash the carburetor cleaner off of the metal parts by washing them in warm, soapy water then rinsing with clean water. Dry them by blowing it off with compressed air. Make sure that all the passageways are blown dry before reassembling.
Reassemble using a NEW carburetor rebuild kit.
DO NOT TRY TO REASSEMBLE WITHOUT USING A COMPLTE CARBURETOR KIT! You will just end up having to do the job again.
The nut that holds on the carburetor bowl has several small holes in it. Some are on the sides and one may be in the end. In order to completely clean the carburetor correctly, you MUST clean these holes with a tag wire or a jet drill. (If a jet drill is used, DO NOT use a drill that is bigger than the hole or the engine will run too rich.) If the Picture does not show up, click on the Blue Text and you will see the picture. There is ONLY 1 picture. The picture may not look exactly like yours but it should be very similar....even if you have an adjustable jet screw...but the tiny holes may be on the sides of the jet instead of the middle
ALWAYS clean the fuel tank and replace the fuel line when doing this repair or you may have to do it all over again. The inside of the fuel line disintegrates over time and these small pieces of rubber will plug up the carburetor too. Dirt and water from a dirty fuel tank will also plug up the carburetor. Find the Model, type and serial or code numbers off of the engine and take them to your local dealer to get the carburetor repair kit.
If you do the work yourself, take pictures or at least make a drawing of where all the linkages, gaskets, and component parts go. Correct reassembly is critical.
If the carburetor still doesn't work correctly, you may have to take it to someone who has an "Ultra-sonic" cleaning machine. This machine uses carb cleaner and ultrasonic vibrations to get the very small passageways clean when traditional methods fail.
Here is where you can get an inexpensive "Ultrasonic Cleaning Machine"
If you don't feel comfortable with this kind of repair I would suggest sending it to a reputable shop.
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