Briggs & Stratton no start

[sunliner]

Have a push mower with a Briggs & Stratton 500E series engine.
Wife mowed part of the yard the other day but ran out of daylight, I was going to finish yesterday...I went to pull the string, and it would not budge. Wife walks by and says "yeah it was hard to start yesterday too" Thanks
Anyway.. I look under the mower and there's a bunch of moss and junk wrapped around the shaft. I cut it all out of there, and after a few tries, I can spin the blade by hand. hooked the spark plug back up and tried to crank it but it will not turn over. String pulls ok, flywheel turns but it won't crank.
I replaced the spark plug, and verified that I do get a spark when I pull the cord.
Took fuel tank off, checked the path from tank to carb, all ok.
Verified that the primer bulb sprays gas into the carb.
tried pouring a small amount of gas into the spark plug hole then putting plug and wire back, Still doesn't start.'
Checked the flywheel keyway. key is there and intact.
I am obviously not a mower repair expert but am somewhat mechanically inclined..and also stumped.
One thing I'm not sure if may be an issue...there's a pull rod that appears to be govern the carb. pulling it back closes a butterfly valve in the carb...but I can't tell what's supposed to actuate that rod normally. maybe something came loose (?) or would that cause a no start condition? Any help welcomed...thanks

 

[bertsmobile1]

:welcome:

If you have fuel, spark & compression then the engine should start, if the spark is happening at the right time.
So verify the timing by taking off the blower cover, then the nut / bolt / starter clutch that holds the flywheel and check the position of the flywheel key

 

[ILENGINE]

Something that I have run into with the new ohv briggs push mower engines is they are VERY picky when it comes to fuel quality. so may try changing out the fuel with some fresh fuel just purchased and see what happens.

I have had several this year that the fuel would pass the fuel quality test sticks, but won't fire a lick on what is in the tank. Drain the fuel from the tank and carb, put in different fuel and will start on the first pull. Have had two trimmers this summer do the same thing with fuel.

 

[sunliner]

thanks guys...
key looks good. since I've got fire at the spark plug, but not even an attempt to start when I put gas directly in the cylinder, do you think maybe compression is what I'm missing? Do you know how the governor on this thing works? I see the pull rod, and spring, and the arm attaches just under the fly wheel cover...but I can't tell what's supposed to move it to close that valve

 

[bertsmobile1]

You might like to give some starter fluid a try.
The exact set up of the govenor varies from mower to mower.
However when you move the throttle it should pull on the spring (s) and open the throttle butterfly fully
As soon as the engine fires the govenor moves and closes the throttle down till the force on the govenor balances the force applied by the spring,
Take a photo of what yours looks like .
The set up on these motors is pathetic to say the best so if you have pushed it under some thick bushes, bumped it on a fence etc etc it bends and then gets out of position.
A hard squirt from a hose can knock a spring off and that is before you get to problems with the govenor itself.
Two pretty pickies please, first throttle closed second throttle open.

 

[sunliner]

I'll get ya a couple of pics up in a bit.
As for the throttle...well there is not one. I have a pull rope and a 'dead mans handle" and that's the extent of the controls. this is a Home Depot $150 lawn mower.
Looking into the carb, it appears that the default plate position is open, pulling on the rod by hand closes it until released and the spring pulls it back open. I'll pull the cover and get you guys some pics of both ends of the governor system.
Might give the starter fluid a shot...just curious how that works compared to gasoline.

 

[bertsmobile1]

Around 3% to 5% by volume of what you put in the tank is a starter fluid.
It is what you smell on a hot day.
Only gasses burn so the small amount of "volatiles" or "aromatics" ( same thing , different name ) included in the mix is there to evaporate to a combustible vapour in a cold engine.
The amount varies, more in winter mixes less in summer mixes.
Because this is designed to become gasseous at room temperature it can, and does evaporate out of the fuel so what is left behind just can not burn in a cold engine.
We call this stale gas.
You can put it in your car and it will run fine just so long as there is enough good gas to start the engine.
The number of things that all have to occur for this to happen makes it appear to be a random event but it is not.
It gets real confusing when the mower with the gas you bought two months ago works fine then you refill with gas you bought 2 days ago and the !*## thing just won't start.

 

[sunliner]

I wound up taking a few pictures...key way, carb plate, governor linkage and where the actuator arm goes etc....thanks for the assist.
http://smg.photobucket.com/user/sunliner/library/mower?sort=3&page=1