Briggs & Stratton Lawn Mower Won't Start

Husqvarna 700 Series push lawn mower. 2 years old.
Briggs & Stratton Engine, Model No. 1006 02 2144 B8

I took it out of winter storage this year, and it wouldn't start. Right away, the cord was really hard to pull. I took the flywheel cover off and was able to move the flywheel by hand and eventually it losened up enough to be able to pull the cord, but it still wouldn't start. I drained the gas and put fresh gas in and changed the oil. Still no start. Installed a new spark plug and tested the spark - it has a spark. I put my thumb over the spark plug hole and felt compression.

I tried putting some WD40 in the carb, and it would start but eventually stop after a few seconds. I'm guessing it just burned up the WD40 and then quit. I took the carb off and carb bowel and noticed the carb needle wasn't sliding back down, so I ordered a new carb kit and installed all the parts in the carb kit. Still won't start. I tried taking the carb bowl off, and there was gas going into the bowl. The spark plug is also wet after trying to start the mower.

I don't know why, but after a day or so of sitting, the pull cord is hard to pull again, and I have to "massage" the flywheel in order for it to loosen up enough to be able to pull the pull cord and try to start the engine.

I'm not sure what else to do at this point.

 

Probably you're getting gas into the cylinder from a leaking float valve. That would explain why you have to "massage" the engine around a couple of times to get it to turn over. You're working the gas past the rings and valves to empty the hydro lock.

You likely have gas in the oil and need to change it again. But first you need to get the fuel controlled. If you can gravity feed the carb/float valve check it for leakage with the bowl off and a light pressure up on the float to seat the valve. Then work with cleaning it or replacing the float and/or valve until it shuts off the fuel completely.

You can clean those float seats with a little Comet kitchen cleaner on a Q Tip.

With the carb cleaned and the float valve working like it should, you'll be up and running.

 

When we replaced the carb needle we took the carb off and cleaned it in a parts washer, so the carb is as clean as new.

There may be gas in the oil, though. I didn't change the oil when I brought it out of storage, just added some to get it to level.

 

Did you find the jetting hole in the bowl nut? That one is the most missed.

 

I removed the bowl to check the bowl nut, and it doesn't have a jetting hole.

 

Of note is that the pull cord wasn't difficult to pull this time. It was as smooth as it was last summer.

 

I also opened up the valve cover to check the valves and they're moving fine. No damage in there.

I also changed the oil.

 

I removed the spark plug and put a couple tea spoons of gas through the spark plug hole and it started and ran for a few seconds and then died.

 

You're not getting gas through the carburetor. Is the gas flowing through the float valve into the carb bowl? If it is then you have jetting passages clogged. You might try Sea Foam in the gas - about four ounces to a quart. Put it in the tank then choke the carb while you turn it over to get the mixture into the carburetor. Let it sit, then try to start it. Use the priming through the plug hole if you need to.

 

Do you mean the float needle? Yes, fuel leaks in through the needle into the bowl.

 

Put some Sea Foam in the gas and got it started by putting gas in the spark plug hole. It ran for a few seconds and then died.

When it runs for a few seconds, it spits a bunch of black liquid out of the exhaust. I'm not sure what it is or what that means.

 

Sounds like your mower was stored with the engine tilted and oil got in the cylinder. Clearing it should help it turn easier and it will probably smoke like a freight train for a few minutes until it burns it all off.

 

I took the exhaust off and drained it. There wasn't a lot of oil in it. It still spits oil and smoke when I start it by putting gas in the spark plug hole, but not as much as before.

Still won't start though.

 

I gave up and brought the lawn mower into the shop. But I won't have it back for probably a couple of weeks as this is the busy season.