lawnmower won't start

[dave.bridges]

I have a Murray lawnmower with a Briggs and Stratton 6.0 HP engine that dosen't want to start. I tried new filters, spark plugs, fresh gas and checked the primer pump. I just pull the cord and nothing happens. When i had the filter off I noticed that there is a spring which connects the throttle lever to the carburetor choke plate which looks pretty worn out. When i move the throttle lever, nothing happens to the choke plate (although I can move it manually). Could this be the reason for the thing not starting? Or does anyone else have any better suggestions?

[willshak]

on 8/24/2007 10:04 AM [e-mail] said the following:

Unless you have an automatic choke, the throttle lever does not move the choke. The choke lever moves the choke plate, whether the engine is running or not. Perhaps you are flooding the engine. Try a little starting fluid (or choke cleaner) sprayed into the throttle before starting.

[ransley]

You need fuel, air and spark, if starting fliud does nothing remove and groung the plug and pull the cord to see if its electrical

[mkirsch1]

Check for spark. Pull the plug, stuff the wire back on, and lay the threaded end against a head bolt on the engine. Pull the cord. If it sparks blue, you've got spark. $20 says you don't have any spark.

Did you hit anything with the blades recently? I don't know if they still do this, but the flywheel used to have an aluminum key that would shear if you hit anything too hard. Instead of twisting off the crankshaft, the flywheel shears the key.

[gfretwell]

Squirt some gas in the carb, open the throttle all the way and pull. If you can't even get a pop I bet you have no spark. It is usually easiest to check spark with a helper pulling the cord while you watch. You can usually just stick a screwdriver in the end of the plug wire, hold it about 1/4" from the block and have your helprer pull the cord. You want a hot blue spark. A thready yellow spark is marginal and if you can't get 1/8" out of it the engine will not start. These engines have points that can wear down. They may be under a cover, out where you can get to them but older or cheaper engines have them under the flywheel.

[limeylew]

You might want to take the bowl off the carb. and see if it has any 'crap' in it.

If it does, clean it out, then remove the gas tank and clean it, too. (this is where the crap accumulates)

This works for me and I hope it will help you.

Lewis.

*****

[SteveB]

wrote

snip

I know about cars. Enough to do a valve job or change a crankshaft.

Lawnmower carburetors look to me like fine watches. Small precise springs. Multiple bell cranks. Lots of little things that have to work together as a fine orchestra.

I thought I knew enough to fix my own. It's just a carb, right?

Ended up taking it to the shop. The guy said it was a combination of old gas, crud, and a spring that worked loose.

Fifty bucks later, I'm mowing my lawn instead of fighting a lawnmower carb.

Take it to a reputable shop. If it don't run right, take it back until it does.

Make sure that they say it's guaranteed to run.

Steve

[gfretwell]

A carb will make it run bad and stall a lot, maybe not even really ever getting up to speed but if you squirt gas directly in the carb and it won't run for a second the carb isn't your biggest problem. That is true of cars too. I have seen guys get an outboard to run long enough to get back with nothing but a ZEP spray bottle full of gas. The fuel system was full of salt water.

[HeyBub]

Saw a cartoon in a medical magazine. Car mechanic looking at the part in his hand as he says to the owner: "There's a lot about carburetors that science still doesn't completely understand."

[Steve]

About 40 years ago an auto mechanic told me that "carburetor" was the French word for "Leave it alone."

--Steve