By gd21 1
I have a Briggs and Stratton 12hp engine in my ride on mower that will not start. I have replaced the battery and starter, and have cleaned the carburetor. The engine turns over slowly as if the battery is low on charge (although I have charged it up) and there is a good spark at the plug. I have tried jump leads off the car, but it does not help. Any ideas?
By gd21 from Sunshine Coast, Qld
April 6, 2011
Go to youtube type in cant start whatever model mower wont start and lots of videos will show you how to. All kinds of mowers. No harm in trying.
My mower with a B&S (Briggs & Stratton) engine won't start. Per feedback from others concerning similar problems, I took plug out still attached to wire, there was no spark when I pulled cord. The plug snapped in so it had a good connection. The first time I pulled, my wife said it shocked her, but no spark. (Holding it in the wrong place?) After that, nothing. It was daylight and in the shade, would we see a spark? Also, a couple of weeks ago it started fine with the old gas still in it. Then I changed the plug, filter, oil and blade. I didn't change the gas, but I did add new gas. I also rinsed it off with a hose pretty thoroughly. Any of this give anyone any ideas? I'd appreciate any tips. Terry from Charleston, SC
If you washed the motor, it sounds as if you have water in the gas. Take the bowl off at the carburetor, and see if there is any water in it. Pinch the fuel line off so you don't have a gas spill. If there is water in the gas, drain it out and try some new gas. (04/13/2006)
By Tom Mann.
I would also dry out the fuel tank and refuel with fresh gas. BUT... I just bought a new push mower with a Brigs and Stratton motor last year from Walmart. And once the fuel gets down to a quarter of a tank or less, it will not pick it up to start no matter how many times you push the bulb to prime it. You may need to simply add more gas. Hope this helps. Sherry (04/13/2006)
By Sherry Nelson
As others have mention I would clean gas out of the carburetor and fuel line. Onetime I added a stabilizer product to my gas in my mower and let it sit over the winter.In the spring the gas had turned to a jelly consistency.Had to clean fuel lines and carb.Started fine after that with new gas. (04/14/2006)
Thanks for the feedback, but it still won't start. I've drained all the gas out as best as I know how. (Just took the bowl off the bottom of the carb.) I even went and got new gas, still no luck. By the way, I do have a spark, so it's not the plug. I put a little gas in the plug hole and it tried to start for a second or two, but that's all. Is it time to replace the carb? Is that something anybody can do? Is it time to take it to a repairman? Help! (04/14/2006)
Mystery solved. It was a gasket. A gasket! All that trouble. Thanks for the help. (04/15/2006)
It sounds like the ignition wire has a short in it. You may have to replace the magneto coil and wire. It is located under the engine's top shroud. (10/06/2007)
The Spark Plug needs to be grounded to the block. I use insulated pliers or gloves and hold the spark with wire attached, plug to the engine block. I would imagine it is getting a spark if there was a shock involved.
It may have water condensation in the gas tank / line. If it has water in the gas line or tank, you can take it to a repair shop and they will do it in within 30 minutes time for typically 50-80 bucks, or do it yourself. I was told water in tank or gas line was not a covered warranty issue.
I read on another site (do at your own risk):
1. remove the gas line from the gas tank and have container to catch the gas coming out. You may need two containers. One to catch the gas thats coming out and another, larger container to dump the gas into.
2. Once tank and line is empty, locate the carburetor bell housing. On a Briggs and Stratton engine, it looks like a silver bell. There is a 1/2" size nut at the bottom. LOOSEN, but dont take apart, and let the gas leak out, mine only leaked out 3-4 tablespoons of liquid. Once it stops dripping ( 3 minutes or less) , tighten bolt and put all gas lines back on.
3. Clean up excess gas spillings, and add more known good gas in tank, and about 1/4 or less of dry gas or carb cleaner. Apparently Lowes sells a product that helps remove water out of gas mower tanks better than Isopropyl Alcohol.
4. If accessible, I removed the air filter and had a folded napkin ready to help block that hole . I had my son try starting the engine, and it started, and I used the napkin to block air flow. It helped suck out all air and water out of the mower. Just before it was ready to stall, I took napkin off hole. If mower stalls, start it again, use napkin as necessary, repeat again until it it runs normally. Only had to use napkin twice.
Make sure your gas is good, it can be cheap unleaded, and it should work fine. if it doesn't it either has a Boatload of water in the machine, or thats not the probem.
Hopefully this helps and makes sense. (11/07/2007)
By major tom
I'm working on a 12Hp Briggs which powers a ride on mower. It won't start and a compression test revealed it had only 7psi dry and 10psi wet. I've stripped the engine bare and can't find a single thing wrong with it. The engine has completed perhaps 100 hrs. Everything inside the engine is as it should be. It has electric start, so I would have expected more than this small amount. Has anyone any idea what the compression pressure should be?
David from England, UK
The Briggs with next to no compression, we found the fault in the end. Careful (very careful) inspection of the cylinder head revealed a burn mark where gas had been leaking past the gasket. Obviously very little was leaking past but on reassembly of the engine, cleaning the carb, changing the fuel and basically doing everything we could think of, she starts and runs fine. Hopefully this info will help some of you other guys out there with similar problems.
Should be around 60-80psi. (06/01/2008)
I have a Briggs and Stratton riding lawn mower, Model 42A707. I just replaced the battery. When I turn the key, you can hear the starter spinning, but the gear on the top of the starter will not pop up to engage the motor gear. Does anyone know how to fix this? Thanks.
By Pengteo from Redmond, WA
I asked my husband about this one and he says: Two possibilities come to mind. One is the cellanoid which makes the starter engage the flywheel and could be stuck. Two is the pin that holds the gear in place could be missing, or the gear on the shaft could be stripped off the starter. Pull the starter out and check it. All the little clogs would be gone on the gear if it needs replacing. (04/07/2009)
Lorelei, your husband is good! I found the plastic piece broken and fly wheel could not go up. So I removed it and brought it to a repair shop. They replaced it with a new fly wheel, plastic, spring. It was tested fine at the shop. I brought it home, installed it back...guessed what, that fly wheel won't engage with engine wheel. It just spins and spins but will not pop up. I called the shop guy and he said simply remove all spark plugs..but it was the same situation. And he is off the clock at 5pm. Any input?
I have a 14hp Briggs engine on my lawn tractor. It will not start, it has no spark, and has plenty of gas. I have checked all of the safety switches. I have actually jumped them out and still no spark. Where else can I look?
By skynyrd57 from PA
For those who can't get a spark; Did you make the sure the spark plug is clean - that the electrodes are not corroded or clogged with soot or oil? Also, when you tested for a spark, did you make sure the earth electrode was firmly pushed against part of the engine casing that was bare metal? If both of these are yes, then the next place to look is the coil that fires the spark plug. Use a multimeter to check that all the coils are okay. (05/18/2009)
My mower has a 16 h B and S twin engine. It has fresh gas, new oil and good spark plugs. The mower will not start. Any ideas?
By alan2902 from PA
There's a dozen things that could cause this problem. Start with the fuel line, as it might be clogged. Could be the starter has gone bad. Have you checked your manual to look for trouble shooting ideas? Here's links you might check out.
Thanks for the help. I pulled the cylinder heads and found that I have one stuck piston on the left side and one stuck intake valve on the right side. Time to make repairs. Not sure if piston is stuck or the or the connecting rod snapped, I would guess the rod is the problem. Thanks again for the ideas. (06/03/2009)
My son thought he'd get my mower ready for me and over filled the oil. 2 uses and it won't start. I figured the spark plug was carboned up so I pulled off the rubber cover, unscrewed the plug and cleaned between the post and metal piece at the end (there's a gap). Use a nail file or emery board to remove the soot, and it starts just fine. I had to drain some of that oil too. (06/04/2009)
Our riding mower will not start. It's a very long story that goes back about 3 weeks. In a nut shell, the engine has been rebuilt, carburetor has been rebuilt, we have fuel, we have spark, new battery, new spark plug, compression is good, the mower just turns and turns, but will not start. Timing has been triple checked and is perfect. It wants to start so badly (and so do we). Any ideas? It's a Briggs and Stratton model 31C707, Type 0603E1.
By starrah3 from Roanoke, VA
Inside the gas tank on a tube is a tiny filter and it plugs with junk, just buy a new one and put it on. (06/11/2009)
I had a similar problem with my mower until I emptied the tank and put in some fresh, premium gasoline, then it started right up. It's worth a shot. (06/11/2009)
I would check to make sure all "safety's" are hooked up, and if yours has a transmission disengage, make sure it is engaged. (06/12/2009)
There may be some water in your gasoline. Drain it and replace it with fresh gas (not from the same gas can), and try again. (06/12/2009)
I have a Briggs and Stratton motor on my riding lawn mower that will not spark. Thought it might be the magneto and replaced it. No joy. How do I know I am not getting a spark? I pulled the plug wire and turned over the engine and put the wire next to the block hoping to see a spark, but I did not. Is there anything else to check to see if a spark is there?
By vincentb from Lakeland, TN
I know this sounds silly, but did you replace your spark plug with a new one? Might be worth a try. (06/30/2009)
My Briggs Statton push mower won't start. I put fresh gas in, checked the oil and the spark plug. What could it be?
By Carol from Peachtree City, GA