B&S 3.5HP Will not run

[Tristan2021]

Hello i have a 3.5HP briggs that has great compression, great spark, good key on flywheel, clean carb, proper valve clearence, and gets gas into cylinder and still willnot run or try to run. im lost on this so any help would be appreciated. Thanks

 

[Michael72]

must be flooding??

 

[Rivets]

Is the spark plug wet? If not spray some carb cleaner into the cylinder and see if it will fire. Are you sure your fuel is fresh? You have everything you need, so it should fire. Some plugs will fire outside the cylinder, but not under compression.

 

[Tristan2021]

Is the spark plug wet? If not spray some carb cleaner into the cylinder and see if it will fire. Are you sure your fuel is fresh? You have everything you need, so it should fire. Some plugs will fire outside the cylinder, but not under compression.

i will buy a new spark plug, i have to admit i just cleaned and gapped the old one

 

[Boobala]

IF you have one ..... ( I don't think the smaller Briggs do) check the low oil pressure switch.... and a looooong time ago I heard a plugged muffler was the culprit in such a case ... ( last resort ) Please keep us informed ....... it helps EVERYBODY to share the knowledge .... persistance will prevail !! Boobala :smile:

 

[reynoldston]

Hello i have a 3.5HP briggs that has great compression, great spark, good key on flywheel, clean carb, proper valve clearence, and gets gas into cylinder and still willnot run or try to run. im lost on this so any help would be appreciated. Thanks

Recheck your work, you missed something. Spark, fuel, compression, timing. You are missing one of these or it will run. How are you making your test? You are checking your spark under compression right? Checking compression with a gauge or a leak down test ? Installed flywheel with proper torque? Give carburetor a really good cleaning? Don't take any short cuts.

 

[redmondjp]

How fresh is your gas?

I'd dump it completely out. Then remove the spark plug and pul starter cord several times to clear out the cylinder in case it is flooded. Reinstall plug.

Then, to check for adequate spark, spray a shot of starting fluid into the carburetor. If it starts, runs, and dies, you have good spark.

Then add some fresh fuel (non-alcohol is best, check Ethanol-free gas stations in the U.S. and Canada for a station near you) and try again.

 

[bertsmobile1]

Get fesh plug.
They can go off very easily and while they will throw a nice spary in the air, inside the cylinder the spark runs strait down the side of the plug & will do nothing.