View Full Version : lawnboy not starting

04-08-2008, 11:37 PM
I bought a brand new lawnboy last spring. Push mower I believe it has a 4 hp Briggs & Stratton. Commercial unit. I tried starting it today. No go. I took the spark plug out and replaced it. No start. Could it be old gas? Thanks in advance.

04-09-2008, 12:39 AM
I went on the lawnboy sight. They have a troubleshooting section. Engine does not want to start. It say's there are 3 possibilities. Bad fuel (drain all the fuel), clogged air filter (restricting airflow), change spark plug.

Rain Man av
04-09-2008, 12:46 AM
Please supply the model and type information from the B&S engine you mention. Not information from the mower. On the briggs/stratton engine will be a place indicating model / type /code.
For Example 137650 / 4562 P1 / 08022223

Three things are needed to make an engine run. Spark, fuel, and oxygen. Replacing the spark plug is a good first step.

Spark - the coil is responsible for the spark plug firing. If the coil is bad, then it doesn't matter how often you change the spark plug, it will never start. i.e, the coil is bad, the plug will never spark. You can test the spark plug, remove it from the engine. With the spark plug out, put it back into the spark plug wire. You want to grab the spark plug with a pair of insulated gloves, or a pair of pliers with insulated grips. Hold the spark plug against the body of the motor - something metal - which grounds the spark plug, and have somebody pull on the handle like you are trying to start the engine. If the spark plug sparks, then that is ok. If no spark you may have a bad coil. The coil on an almost new mower should not go out, they can, but it is rare. If your not sure about this procedure, ask somebody familiar with auto mechanics to help you troubleshoot the spark. There is a spark plug tester tool you can buy, if you so desire.

Fuel - Not to make fun, but are you sure there is gas in the tank ? Is there a cut off switch for the gas ?- check the owners manual if not sure. If the gas in the mower was left over from last year - Get it out and put fresh gas in the tank - not more of ole last years gas. Drain the bowl of the carb - if you know how. Make sure that there is not an obstruction in the fuel tank, aka the bottom of the tank. Somewhere there is a fuel filter. Most times it is somewhere in the hose that leads between the gas tank and the carb. Get a can of carburetor cleaner. Remove the filter from the mower and spray cleaner into one end. cleaner should run out the other end freely. If not, replace the filter. It is possible that the problem lies with inside the carburetor, you should clean it out. If you left gas in the mower from last year - gas over time turns to varnish - varnish is a sticky , gooey substance that carbs do not like. You will have to have the carb cleaned, if this is the case.
If you are capable of dissambling things and putting them back together without having left over pieces. then you should attempt cleaning the carb yourself. If not, the worst thing is you take the mower and the carb to a repair shop and let them put it back togther.

Oxygen - if the air filter is clogged, the engine is suffocating and no amount of spark or fuel will make the engine run. Clean or replace the air filter element. Very simple and easy thing to do. Pay attention to things as you take them apart.

04-09-2008, 12:58 AM
Thanks buddy. That's been a helpfull post. I've got a rainday tommorrow, will take you're advice and give it a go.

Rain Man av
04-09-2008, 01:51 AM
Sounds like my advice was along the same lines as that of lawn boy.

Good luck and please let us know you fared. Inquiring minds want to know.:drinkup:

Jay Ray
04-10-2008, 10:34 AM
I had a 4hp B&S, a Quattro engine I think they called it, that had the carb built right on top of the fuel tank (vacuum carb with fuel pipe). If the tank was not at least half full it would not start. There was probably something wrong with it but it was not worth the time to look into it. I just filled it up every time it was used.

04-10-2008, 11:08 PM
I drained all the fuel. Put fresh gas in, change the spark plug,checked the spark plug wire and changed the oil. No start. I took it into a local outdoor power equipment shop and the guy said that it most likelly needs a carb cleaning job.