I have a 2001 Sears Craftsman Key start self propelled mower that is very hard starting. My parents quit using it because it was so hard to start. It takes 10 to 15 pulls at least (battery bad so no Key start)
12H807
2632-B1

I have cleaned and rebuilt the carb.
new air cleaner and spark plug
Used 2 or 3 gaskets behind air cleaner (to carb)
replaced primer bulb and can see stream of gas each time primer bulb press.
checked and reset the air gap
replaced the flywheel key just to be sure.

When I check the spark it seems to be weak. Jumping the mower and turning over with the key the spark seems to start big and then sort of weaken up. I've tried several plugs with the same result.

It always runs good once it is started and will start easily after it warms up.
Anything else I can check. I have not done any compression test on it and I have not checkd the valves or head gasket. Any chance these may be causing the hard start issue. I did move the alternator out of the way because there was no battery in it. (I didn't think that would cause any harm????)

Once again I appreciate any help you can give me.

Jack.

I would check the valve clearances for a start. You cannot look at the spark and tell if it's weak or not, so that is not a good indicator.

Thanks for the reply and the explaination. I always appreciate not only your answers to our problems but the reason why. I will check tonight or Friday night. To adjust the valves I am thinking I will need a tool or two. Could you tell me what I might need just to remove the valves. (I am guessing that the only way to adjust is to grind a little off.) Thanks again 30yearTech

Thanks for the reply and the explaination. I always appreciate not only your answers to our problems but the reason why. I will check tonight or Friday night. To adjust the valves I am thinking I will need a tool or two. Could you tell me what I might need just to remove the valves. (I am guessing that the only way to adjust is to grind a little off.) Thanks again 30yearTech

Your Welcome!

There are special tools that make removing and installing the valves on this engine easier. I can do it with a screwdriver and a pair of pliers, but I have been working on engines for a long time, this may not be the easiest approach for you.

Before you remove anything, the only tool you will need is a feeler gauge. You can check for proper valve lash by removing the oil breather (located behind the carburetor) this will tell you whether or not you need to remove the valves to adjust. You do need to grind the valve stems to set the lash on your engine, if any adjustment is required.

I checked the valve lash and it was way too much. I pulled the head and found the exhaust valve seat had come out a little and was holding the exhaust valve open a little. I tapped it back in ,put it back together and it starts immediately. Thanks again for the diagnosis. Now.......I'm while I'm waiting for my new head and valve cover gaskets do I need to do anything with the valve seat? I am guessing that the valve must have been stuck at some time to cause this. Thanks again.....Without you and all the others on this site I wouldn't have even attempted this a year ago.

I checked the valve lash and it was way too much. I pulled the head and found the exhaust valve seat had come out a little and was holding the exhaust valve open a little. I tapped it back in ,put it back together and it starts immediately. Thanks again for the diagnosis. Now.......I'm while I'm waiting for my new head and valve cover gaskets do I need to do anything with the valve seat? I am guessing that the valve must have been stuck at some time to cause this. Thanks again.....Without you and all the others on this site I wouldn't have even attempted this a year ago.

Usually the engine gets overheated, and this is when the valve seat comes loose. You need to peen all around the seat to make sure it won't come back out when the engine gets hot.

Not quite sure what you mean. Would that be like taking a punch around the top or bottom edge???? I might be able to check my manuals or find something on-line somewhere also. Thanks for the help.

Using a center punch, start near the edge of the seat in the engine block area in the 12'oclock position, then 6:00, 9:00, 3:00. Then continue all the way around placing punch marks around the seat. Using a center punch pushes the aluminum around the seat in towards the seat help keeping it in place.

Best of Luck....

Thanks again for the support. The mower will run good now so I will peen the seat and hope it stays in. I only use this mower to do a very small area but I have somewhat of a sentimental attachment to it. I would like to keep it running as long as I can. Thanks again......until next time ....have a good day.