OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Please help - Briggs & Stratton not starting

Hi! Newbie here.

I have a briggs and stratton engine on a rideon mower.

I had turned the mower on it's side to fix something underneath. What I missed was that all the oil ran out into the air filter.

When I started it, the power slowly disappeared over 1-2 minutes, the engine was somewhat smoky, and eventually the engine gave up (perhaps with a [small] bang, cannot recall).

Then I noticed the oil run out. I took out and replaced the air filter, cleaned up any visible oil, refilled the oil (a fair bit had run out), and tried to restart.

Result is that each time I try to start it, there is a "clunk" noise (<1 second) and the engine visibly turns 2-3 millimeters then falls back.

The clunk or click is not repetitive and the mower just had a new batter a little while ago (and it's hot outside).

I then manually turned the engine a quarter turn back or forward (using the top grill), and then trying to start there is still a clunk noise, but this time only after the engine turned that quarter or similar turn back, and this time with some smoke.

The mowing deck is not engaged, and the brake is depressed whilst doing this (both required as otherwise electrical safety is not engaged and engine won't stat).

What could be causing the engine to do this clunk/getting stuk?

Some online research shows it may be a starter motor, but it rather seems like something is stuck or holding/terminating the engine run.

Can make photos or give more info if needed.

What do I do? Thank you!


Also shredded my tire at the same time so not a happy chappy

Take the spark plug out and see if it will turn over

Thank you @NormK

1. Removed spark plug, tried to start engine, same result (clunk)
2. Rotated the engine almost full circle by hand, hit some sort of "metal-to-metal" end
3. Rotated back the other way, full circle, hit some sort of "metal-to-?" end
4. Instead of using top grille, turned engine by using wheel underneath engine. Was able to make a few rotations. Something seemed to have loosened, though I am not sure what. The wheel under the engine is belted, but was free/not engaged at all times both before, during, and now.
5. Cleaned out spark plug (sanding paper), refitted, tried to start, engine turns over but rough and clunky
6. Did some more manual turning and engine seemed free-er. Tried to start again and bit rough but drove up gas/speed, towards and on choke.
7. Engine now seems to turn freely (don't ask me how that happened, but it does), but it does not start. It rotates at reasonable speed, just does not start. Spark plug is in. Tried quite a few times even after letting it sit for a while.

What would be the next step?

Ok another dumb question, was this motor running before you tipped it on its side?

Sounds to me like the conrod has let go, pull the spark plug back out and see if the piston is moving up and down. if it is OHV just put a screwdriver in the plug hole and turn it by hand, if it is side valve you might be able to get a long skinny screwdriver in there to check, otherwise turn it over without the plug and listen for the air going in and out

@NormK Thank you! It was going fine before I tipped it on the side. Maybe a little hard to start, but only let's say 10% so. It died within 1-2 minutes of turning it back to normal and running it.

This is a photo:



Which of the options you listed do I proceed with please?

As nath said, do those tests

I get a kick out those posters that act like the date code for these numbers are not important or that we are wanting to track them down for thief. Now that might the reason Briggs has now started using serial numbers on their engines. But most time just helps to determine which parts were used.

But I wish people would stop rolling their engine on their sides as creates all kinds of problem. I surprise they are rolling their vehicle on their sides just access the transmissions. It might be only a weight issue.

I know AVB, it would initially appear that is a serial number

For Roels information, there are hundreds if not thousands of motors with that identical number. it will be something of the nature of "91 08 09 58"

As they make hundreds of motors a day, therefore all have same number

Meaning made 9/8/1991 in plant 58, which may be Wauwatosa Wisconsin. If parts are looked up in briggs online catalogue, there are often clauses of use x "before 5/6/1990" or use y if made after 6/6/1990.

Therefore these numbers are crucial

@NormK - yes I was planning to. I had mistakenly thought that @nath's post was yours. Hence I posted a photo to ask if this was an "OHV" as @nath suggested.
@Nath - which test do I use? Is this an "OHV" ? (Overhead engine?)
@AVB/Tyler - ack, I did not know. The code is 000512ZD.

Hi Roel, it is a sidevalve, that is one question answered. My thinking is that with the motor on its side, oil has got past the rings and into the combustion chamber and when you have gone to crank it it has snapped the conrod. Hoping not but trying to think what the clunking is

It is a good possibility that the rod seized and then broken as it don't take long to do this when no oil is present.

Hi Roel,

I started to think it would be a snapped conrod but the engine still ran rough after you freed the clunk. So, can't be the conrod coz once the conrod breaks, there is no enough compression to start the engine and to push the piston up but the engine still starts. You feel a clunk when you spin the flywheel grill manually but you freed the clunk when you spin from the underneath because it has more torque/force. One thing I can think of related to tilting the engine is a foreign object that slide and stucked into the flywheel magnet between the grills which product a clunk when you rotated it 360 degree. Possibly forcing to free the clunk also could knock off the ignition coil which possibly the engine won't start. Worth checking the ignition coil.

Cheers,
CM