Devon from Bothell, WA
There could be range of different things to isolate put your finger over the spark plug hole and turn over the motor. if there is no compression it won't suck the petrol in through the carb. Lack of compression could be rings or valves assuming thats fine move to the carb blow out all jets in the carb with a air compressor if they are blocked that could cause petrol to not get through. other wise check that the choke mechanism is working take off the air filter and when the choke is on the butterfly should be in the closed position if it isn't it needs to be adjusted. If it is the pump type the pumping mechanism may be faulty you will need to replace it. if there are any filters in the line they may be blocked you will need to clean filters. sorry can't do any better without knowing make model or type of briggs motor hope that helps brent nz (03/30/2007)
By brent nz.
Thanks Brent for the info. The engine is a 4.5 hp (5 years old) and could not find the model number. I will give it a wirl. (03/30/2007)
I have a B&S quattro 4 hp that is 9 years old with the same problem. Have changed out the diaphragm for the carburetor but no gas is going from the bulb. No gas is coming from the tank. Hopefully someone can help us both (04/08/2007)
I have a similar problem with a Briggs&Stratton mower engine - Model 101908 (4HP). Mower has not been used for a while, but after a few pulls it starts and sounds ok - but after about 5 seconds, stops.
What can I do or does it require professional help?
We have 2 Briggs & Stratton push mowers. One we bought in 1991-1992 & still runs. My husband says there is fuel additive for lawn mowers that he uses, think it's made by Gum-Out. It has a pre-measuring cup on it & the liquid is green. You might have rust or varnish in the tank, if you've left gasoline in the tank. He's always run his mower empty before storing it for any time at all. You might try taking the air filter off & spraying the in-tank with WD-40 to see if it will start. Check your spark plug to see if it's getting a spark. Sounds like it might be time for a new mower. Wal-Mart more than likely, will have a mower cheaper than you might can pay for repairs. Or you might can go to Home Depot or Lowe's to see if someone might have bought a new mower & returned it for some reason & get a discount. (we got our 2nd mower like this, at Home Depot & it still runs.) (04/25/2007)
Ok I don't know what much is called on a lawn mower, but I can tell you what it does & how to fix it. Firstly if your primer is not getting gas to the bowl it may not be the carburetor. on the underside of the bowl there is a screw. Loosen it just a little, put a little gas in the tank, & prime it. If it leaks then you know that it is not your Carburetor. If it doesn't then at least you have isolated the problem between the carburetor & the bowl.
If it doesn't leak: Relax this should be a quick fix. Check the seal between the carburetor & your bowl. Most often this is broken just take it to a parts store & replace it. If it is unbroken, open your bowl & pull the pin that holds the bobber in place. There should be a little plug that goes up & down with the bobber, located under the part of the bobber that you just pulled the pin from. It should come out with the bobber if not then there is your problem. If the bobber is broken where it should hold the plug in place, you either need a new bobber, or a whole new bowl. (It is much harder to find a bobber that fits that bowl, then it is to find a bowl that fits that mower.)
If the bobber has the plug with it when it comes out. Then blow air into the place that plug just came from. If it does not go all the way through, get a new bowl. You can fix the old one, but I don't know how to put how to do that into words.
If air comes out of where the where the gas tank attaches to the bowl Blow your hose. If that doesn't work soak it in a mix of old gas & oil for a while. (Preferably 30lb)
If the bowl does leak: you want to check your spark plug by having someone hold it against some mettle. If you get a spark put it back in, & check every hose & pipe between the gas tank & the combustion chamber. (The part you screw the spark plug into.) More then likely you have a clog in something. If you find it, Blow it out with an air hose. If that doesn't work soak it in a mix of old gas & oil for a while. (Preferably 30lb) If it still doesn't work your pistons are probably out of line. If it still doesn't work, go to a pawnshop & buy a new mower.
The original post only mentions that the primer is not sending fuel to the carb. This is a common problem on B&S engines with the square airfilter box [about 4x6] on the side of the engine. There is a fairly complex gasket between this filter box and the carburettor which also serves as a channel between the primer bulb and the inlet manifold side pipe. If this gasket is worn or pierced, then the primer bulb will not be able to build up any pressure in order to inject fuel. The engine should still start OK in this case, but may take rather a lot of pulling. New gasket only costs a few dollars. (07/29/2007)
By Tom NI
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