Craftsmen 16HP Electric Start 42" Mower
Model 917.270680
With briggs and stratton motor
Hello, I think I may of figured out my problem after searching this site for a few hours. So please let me know if I'm on the right track.
To start out, I went to mow the lawn and noticed right off that the gas tank was empty... like near bone dry.. which I thought was odd because I topped it off last time I mowed and I dont use a full tank to do my lawn. I looked at the wood floor for a leak or signs of gas damage and didn't see anything. I shrugged it off and filled the gas tank again. I went on to try to start the mower a Bunch of times but more or less this is how it played out.
Video found here https://youtu.be/3vgUTein_ko
What you are hearing is a quick charge switched into start mode to give additional power because I thought maybe my battery was dead.
Things of note:
*gas tank oddly empty
*At one point I saw gas spit from the exhaust on to the floor.
*When I took the air filter off to examine it and try to turn over the engine a spray of gas came out of there too.
*I also noticed an oil leak on the floor right after attempting to start the engine a few times.

So after reading these forums I think i most likely have a sticking float? and my gas (what I had left in the tank) filled my cylinders. I also probably has gas in my crankshaft too now, which will require all new oil.
Does that about cover it?

My plan is to first purge the cylinders with a method I read here involving removing the spark plug with the plug wire tied back then turning over the engine a few times.
clean air filter
replace spark plug (cause why not its been years)
replace battery (it needs it)
new fuel filter
add a fuel shut off valve

This is where I get hazy... Do I need a Carb rebuild kit? How do I address the Sticking Float correctly?
I love getting my hands dirty doing this stuff but any pointing in the right direction with some resources would be greatly appreciated.

thanks.

 

You must change the oil as it is gull of gas, you need to clean and rebuild the carb but most importantly is to make sure the float is floating and that the needle is shutting off the fuel, while you are at it I would add an inline fuel shutoff for when the mower is not in use just to be safe. Have a good one. Geo

 

geo made the call.

Easiest way to do this is remove the spark plug, then turn the engine by hand by turning the grass screen. Using a probe like a pencil or wooden dowel, probe the spark plug hole and turn the engine until the piston is at TDC (for this it doesn't matter what stroke). Then drain the oil, leave the spark plug out and the dipstick removed...

Now you can focus on the carb while the crankcase drains and airs out.
If you still have fuel in the tank, clamp off and remove the fuel line at the carb (you can now install a shutoff valve) Using a 1/2" socket remove the bowl nut from the carb being ready to catch draining gas. Account for a washer or gasket on the bolt. Once the gas is drained you can loosely reinstall the bowl and bolt.
Remove the air filter.
Remove the two bolts attaching the intake to the head. Account for an O-ring. There may be one small screw in the air filter housing connected to the elbow to the carb, if so remove that. Make note of the choke and throttle linkage. The choke linkage will slide out of a bracket the end with a long loop. Then you can work the Z-bend out of the throttle and remove the carb and intake and take it to the bench.

Remove the bowl, float pin and needle valve. The needle valve should be rubber tipped so there is no seat to replace only clean. Shake the float next to your ear listening for sloshing. You should have a plastic float which I have only seen one filled with gas. Check the rubber tip on the needle valve and if you see a ridge then replace it, otherwise you can try to clean it and see if it will work.
Using some spray carb cleaner clean the carb through every orifice you can see and find. Take care on the body of the carb not to get crazy with the cleaner on the foam gaskets on top of the throttle and choke stems.
Assemble the carb and intake, re connect the linkages, then loosely attach the intake with the two bolts leaving enough room for a gap between the intake and head. Connect the fuel line and turn on the gas. Wait several minutes and check to see that no gas is leaking from the intake. If not gas is present after 10 mins or so, button that all up, fill with oil, spark plug and try it out.

Good Luck

 

Thank you BFH I'll try that out. Great detail

 

and you need to install this $7 manual fuel shut off valve to ensure it never happens again. Takes about 5 minutes to install and a 9 year old could do it.

http://www.homedepot.com/p/3-25-in-W...8#.UqCkueqEiic

 

.
While it is a good idea and I recommend it for a variety of reasons especially long term storage, it is not a substitute and no guarantee!

 

i did everything this thread suggested over the weekend and it fired right up!
shut off installed
spark plug changed
carb cleaned and rebuilt with rebuild kit
New fuel filter
new battery
oil changed

i was AMAZED at how much gasoline came out with my oil. Had to of been near 100 ounces.

It did run with white smoke for a good 5 minutes before clearing up and running perfect. I either assume i overfilled the oil a little or could that of been from all the gas/oil saturation I had just drained and cleaned up?

anyway thanks all.

 

Probably the muffler burning off the oil. Normal after this kinda thing.