20 Most Recent Briggs & Stratton Lawn-Boy 10640 20-Inch 6.5 HP Gas Powered Lawn Mower - Page 3 Questions & Answers

If the machine is indeed a Briggs & Stratton, then you can go here to their website, put in the model # of the engine it has and get an illustrated parts diagram breakdown. Very useful and quite helpful. Go to:
http://tinyurl.com/3928l5u
Please vote on this solution.

You might have an accumulation of water in the fuel tank/carb.

Drain them both and make sure you put clean fresh fuel in.

The gas can might be contaminated too so be watchful.

Check your spark plug too. Remove it and make sure it isnt water or gas fouled. *(wet and not sparking) A fuel fouled plug usually needs replacement. Water...not so much.

Good luck and be careful!

Don't throw it out. Remove the top plastic cover and it will be easy to access the starter/recoil unit. It should be easy to remove and take that off and diagnose the problem. Post back if need be.

rusted recoil spring or oil/gas in cylinder causing hydrolock.

You need to find a "vented" gas cap for your mower to continue running with the cap on. You can buy such a gas cap for most mowers at Wal-mart or similar department store and it will say "vented" on the packaging.

Has fuel with oil accidentally been mixed to the fuel for this mower? We have had mix oil accident get added it to this lawn mower and it will smoke a lot with 2 cycle oil.

Unless you are certain no oil is mixed with the fuel I would drain and clean the fuel system.
Replaced the spark plug with the new and replace the air filter In addition ensure you do and oil change every 30 hours using a high grade 30 wt oil to include make sure it is not over full.

Hope this tip helps.

r/
David

If it has the primer bulb push on it many times and try starting again

try pulling off the spark plug & boot and hold the spark plug end to a metal part on the engine and pull the rope and see if you have a spark,if so pour a small amount of gas into the spark plug hole and then re-insert the plug and see if it fires,if so then the carburator may need service or rebuilding

take air filter off and give it a shot of starter fluid, if it starts, you have a carberator problem. if it dose not start, check the spark plug.

STOP !

Your lawn mower is has a 4 cycle engine
It does not require oil to be mixed with the gas
The oil for the crankcase should be a 10W-30 or 10W- 40
NO GAS IN THE OIL
What you have is a 2 cycle oil that is mixed with gas for most weed eaters, chain saws, ect
Putting a gas/oil mix in your mower WILL severely damage it destroying the main bearings and could lead to an explosion or fire.
Please be careful

souds like the carb needs cleand out it has stuck open and let the gas run in to the moter

There are no timing "specs", if the flywheel key is good and the magneto air gap is properly set, the timing will be right.
Torque for the rod bolts is 45 INCH pounds - NOTE INCH pounds not foot pounds

Check out the following link that I am attaching. It should assist you in rewinding the pull cord in your mower. Hope so anyway and best wishes.
http://www.youtube.com/watch?v=i3ZMVFi0yqY

starving for fuel, clean air filter, clean carb

lawn mower grade strait 30

i have a riding mower and i get that problem sometimes and what i do to fix it is i take a metal pole and put against the motor and gear on the starter and push when it moves i turn the key and that normally fixes it.

Likely either the engine is flooded or low compression.

A simple go no go compression test is remove spark plug and press a thumb or finger firmly over the plug hole and crank engine. It should forcibly push your finger and make a loud PFFfft sound. No or little sound equals insufficient compression.

If the push rod was not bent, there was no reason to replace. If it was bent then I question how you set proper valve lash with new pushrod as the typical cause for a bent rod is a displaced valve guide.

If compression is OK then likely it's simply flooding and you have a carb float/inlet needle issue. Crank engine, remove plug and if it's saturated with fuel then it's flooded and a flooded engine will not fire, even with starter fluid.

Comment for further assistance.

Check the gap between flywheel and coil

Question edited for clarity and spelling. Question moved from Motorcycles category. Please proof read before pressing 'Post Question'. Your 'Bolson' doesn't exist! https://www.google.com/search?q=Bolsen+1.5HP+158cc+briggs+%26+stratton Surging is usually caused by an air leak in the inlet manifold.

Troubleshooting small engine problems

Briggs & Stratton https://www.briggsandstratton.com > faqs > browse > e... Engine Stalling, Surging or Running Rough. When your engine starts and stalls, it is often due to standard maintenance problems. Prevent stalling problems ... ..