Small Engines (Lawn Mowers, etc.): 5.0hp Craftsman Lawnmower Engine, rough sketch, soft brass


Question
EZ Option 22 inch. model#917.388152

My mower will start, but after a few seconds it slowly dies. If I hold the rubber fuel primer button in, it will stay running, but as soon as I let go it slowly dies. After a few minutes of starting it repeatedly and getting the engine warm, it will stay running but the engine speed goes up and down constantly. It doesn't have the usual horsepower.I was thinking a carborator/fuel problem maybe. I added some carborator cleaner to the fuel but it hasn't helped much. Ideas so I can fix it myself! Thank You.  

Answer
I would say a fuel problem, because this is very common with these engines.

Drain the fuel tank and remove the spark plug...for safety reasons.

Find a small container or old rag to catch gas.  Remove the carburetor float bowl nut located on the bottom of the carburetor.  This will drain the carburetor float bowl.  Clean the nut making sure the small holes are not blocked. Re-install the nut, making sure not to strip the soft brass threads.  Re-install spark plug and gas try to start.

If it does the same thing then you will have to remove, disassemble and clean the carburetor.  This isn't too difficult, but I would recommend drawing a rough sketch and marking how the parts are attached BEFORE you remove the carburetor.  The linkages can be a real pain if you have no idea where they go or how they are routed.  A digital camera would be a good idea.

Once the carburetor is removed disassembly is quite easy.  There are very few parts, just clean all the carburetor holes with compressed air and carburetor cleaner.  Re-assemble in reverse order.

Let me know what happens.
Eric