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engine model - 120000

Hi All,

I don't know much on the history of this engine but I inspected what I could and the flywheel key, magneto, air filter and spark plug are in good condition. I tested with a spark plug tester and I do get a spark.

I did clean the carb and fuel tank and put in fresh gas. I also sprayed in some starter fluid but no firing at all.

Any ideas?

Thanks!

see if it fires with starting fluid down into the spark plug hole..

will do. i did spray some into the muffler and heard a huge pop when pulling the cord.

if you do that and find you have spark, make sure the holes in the main jet/bowl screw are clear.

I’d check to see if you have spark, and like scrubcadet said check the carb again.

ok so i checked everything over again. i used my spark plug tester and i do get spark. but the crazy thing is that if i spray starter fluid into the spark plug hole the machine still does not start or turn over. i did notice the machine has a cheap Chinese made armature. its not the original one. could it be possible that it is not the right one for the machine? the previous owner did try changing the armature so that makes sense. he said that the machine was running fine and then all of a sudden it stopped working.

No bang from the engine with fuel down the plug hole that has a good spark usually means either the timing is very wrong, valve is stuck or piston is not moving.
Then we get to exotics like a big hole in the piston, no rings at all

i took the head off the engine and here are some photos. i pulled the cord several times and it seems the valves are opening and closing properly along with the piston going back and forth without issues. could it be the magneto is not providing enough spark? but i did hear a very very faint spark when trying to get it to start the other day when i sprayed starter fluid down the spark plug hole.

It could a valve clearance issue on that 2014 126M02-1525-F4 engine. It also can be a compression issue with the cylinder as it appears to be an oil burner.

would it help if i cleaned all the carbon (especially around the valve seats) and installed a new head gasket? or is it better to just get rid of the machine?

topgun129 said:

will do. i did spray some into the muffler and heard a huge pop

Click to expand...

What? Spray liquid fire juice into the muffkin? "I want to party with you cowboy". From the movie Stripes with Billy Murray.

That engine has an thermostatic choke level located at the muffler. When it heats up it pulls the choke OPEN.

Remove the air filter cover. Look into the carb. Choke plate should be CLOSED with engine off and or cold.

1.Dump and flush out fuel tank.
2.Verify fuel flow AT carb.
3.CLEAN carb. As Bertsmobile1 said there's clean and then there's CLEAN. Think hospital clean here.
4.Install carb. Remove fan shroud. There is an air vane like arm that has a spring on it AT the carb. Spring and arm should pull the choke plate CLOSED engine off. Arm should move freely.
5.At muffler there is a thermostatic lever that contacts that arm. When muffler gets hot, lever and arm will move OPENING the choke. There are 2 line marks that the arm should be in between. You can GENTLY tweak the thermostatic arm to center it on the arm deal-e-o. Check youtube for videos on it. There's a bunch out there.

If you move the arm engine OFF, you should see the choke plate opening and closing. Verify this.....

Take an old spark plug. Gap to 0.25" or 6mm. That is a quarter of an inch. Check for spark. You must pull the rope WITH A PURPOSE. Magneto needs a min of 350rpm to fire. Don't pull it like my wife and expect it to start LOL LOL.

While the fan shroud is off, clean the cylinder cooling fins all the way around the cylinder. This is a YEARLY maintenance deal in your engine manual. Neglect this and you will have engine damage. These are air cooled and get to full temp in roughly 1-2 minutes. Keep the oil level exactly on the full mark.

Clean all the carbon and wipe all the carbon grit from the bore. Install head and fire it up.

Valve adjustment check wouldn't hurt either.

slomo

topgun129 said:

would it help if i cleaned all the carbon (especially around the valve seats) and installed a new head gasket? or is it better to just get rid of the machine?

Click to expand...

Clean the carbon first.

On older engines like this one, people use Seafoam in the fuel. It breaks up carbon chunks that get into the cylinder and scores the aluminum bore. Not a wise move to use Seafoam right now, or ever. Resist the temptation to use any fuel additive other than real 100% gasoline.

slomo

topgun129 said:

ok so i checked everything over again. i used my spark plug tester and i do get spark. but the crazy thing is that if i spray starter fluid into the spark plug hole the machine still does not start or turn over. i did notice the machine has a cheap Chinese made armature. its not the original one. could it be possible that it is not the right one for the machine? the previous owner did try changing the armature so that makes sense. he said that the machine was running fine and then all of a sudden it stopped working.

Click to expand...

Amazon Ebay Chi'-sneeze magneto alert!!

Are you talking about the ignition magneto? The deal on next to the flywheel/fan that makes the spark? If so get a real Briggs mag.

slomo

i removed the muffler and opened the valve area and noticed that at top dead center the intake valve has no clearance and due to that the valve is not shut completely. the exhaust valve is fine. i assume this is the issue why there is oil burn and no compression, hence the machine is not starting?

thanks!

Most likely.... Flathead clearances close up... and StarTech will tell you he's seen them with Negative clearance.. on flat heads you have to grind the end of the valve down a little teeny bit at time and keep rechecking clearance until the proper is achieved.
On the compression stroke as well?

Need to be at TDC on the COMPRESSION stroke.

post a picture if you can,

i was planning to grind down the valve end like 1mm and then recheck if it creates the proper valve clearance. basically i have a clearance tool like in the attached image and took the thinnest one and i could insert it thru where the valve closes against the head (right next to the piston), however with the exhaust valve i could not insert it thru (meaning a very tight close). seems like because of the lack of tight closing of the valve it creates a lack of compression. the exhaust valve closes tight and has valve clearance.

i took the image at top dead center (piston at top and valves fully closed). the bottom valve has a very small clearance while the top one does not at all (kinda hard to tell in the image).

1mm will be way too much
Firstly make sure you are on the firing stroke and B&S recommends to go 1/4" past TDC
Too easy to to be at TDC exhaust stroke and really stuff things up
THe head should come off & the valve come out .
Valve lash is set by shortening the valve stem ( increases ) or cutting the seat deeper ( closes the lash )

In use the exhaust valve seat wears away which closes down the gap till there is nothing left .
Because it is a strait push ( no rockers ) if the valve lash is just 0 then you take .007" off the stem not 1mm
Pop the valve back in and measure the gap while pushing the valve in as hard as you can with your thumb
With my hands I find around 0.015" measured this way gives me around .009" with the spring on

ok sounds good. i'll recheck with 1/4" past TDC and then if same result then i'll give the valve a very very light grind on the stem. thanks.