View Gardening .com

Three things are necessary for a gasoline engine to start. They meet in the combustion chamber during compression of the cylinder:

1. Gasoline 2. Air 3. Spark

If any ONE of these three is not there, IT WON'T !!!
(START)

The spark plug may be too old or fouled. You can remove and clean the old one, get a new one if necessary.

The air filter may need changing if old and clogged. Some types can be removed and cleaned.

Before trying to start it, make sure there is oil in the crankcase, but do not overfill it. Also make sure there is gas in the gas tank and THAT THE GAS TANK HAS ITS LID SCREWED ON PROPERLY.

If you are willing to get down and dirty with doing this, it is all you need to know except for tightening loose connections and the like, often a problem with vibrating machinery.

If you still can't figure it out, you need someone who is not a mechanical klutz to lend a hand.

No one ever trained me, and I never saw a lawn mower problem I could not fix.

Anyone else can do equally well. Maybe even better.

2006-01-15 11:55:54 by Mower Man

after work stuntin on a murray rear engine rider by my boy MJ

If you 22" blade is hitting the deck, you might have bigger problems. If you tried a new 22" blade and still hit the deck, you need to check the spindle and make sure the shaft is straight, they can and will bend. Second, make sure all the metal is straight and out of the way. I prey it is not the first, especially on a push mower. On a push mower that would be your crankshaft, and very expensive to replace. One that is bent, it will never run true again.

2007-04-17 11:26:28 by J-ROY

Price: $14.99 $14.99

Murray Part Number 774004; 7740043MA
Also Replaces Murray Part Numbers 672763E701 and 671921E701
3N1 Combination Blade can be Used for Side Discharge, Mulching, or Bagging

MURRAY 20" 4.0hp Quatro Briggs & Stratton. The mower fluctuates when it is running and i was told to remove the carburator and give it a good cleaning. i do not have the manual for the mower. Thank you.
where is the model number located on the mower? i'm at work right now...

Look here:

http://www.murray.com/products/combined_ search.asp?search=Model&type=OM

You will have to enter the model number in the box. Good luck!

2007-10-02 17:03:58 by Thank You

Price: $10.56 $10.27

Blade width 2.25-inch
Blade length (measured diagonally): 20.9-inch
Blade center hole diameter 0.85-inch

my lawn mower was runing just fine till.i tilted my riding lawn mower (murray) on its side for 20 minuts removed the blade,sharpend the blade and then put it back on.then i seen that oil was lecking out the air fillter near the gas line.i removed the spark plug drained the oil out of the air filter and the started the mower (without the spark plug in)pump oil out of the pistons and flused gas throw the engine.got most of the oil out.put spark plug back in and started the mower.thick white smoke came out off the muffler burnt oil for about 10 minuts.i have to pour gas under the (air fillter) engine to get it started the gas line is not blocked i think the fuel fillter has oil in it blocking gas from geting into the engine.well anyways is there any thing i can put in the mower the get it to stop back fireing like carb cleaner what ever?of if i let down on the gas the engine shuts off so i push up on the gas and it back fire when it runs not one but most off the time.
yes i got a new air fillter

A lot of possibilities are already mentioned here. Dirty carburetor, fouled plug, etc. Check all the common sense things. I just have one additional possibility to try. Remove the muffler, and see if that helps. Sometimes (especially after burning a lot of oil), soot can clog the muffler, and cause these problems. A motor has to breath both ways.

2007-09-27 15:19:45 by RANDY JR 87

i have a 20" Murray lawn mow and the sound fluctuate when it starts up and running. i change the oil and replaced spark plug.
it start up just fine. it sound normal for a minute and then after that it starts to fluctuate. please help.
replaced new blade from home depot, changed oil and replaced new spark plug. done all this on the same day....
i let it run until the gas were empty and then filled it up with nwer gas and still doing it. it was running just fine last week. i always park it in my garage (this is a walk behind lawn mower). couple of months ago it was doing the same thing but it stop. now it started again after i did the tuneup....

Sounds like the carburator got gummed up over the winter. There's a chance that it will flush clean after a few tanks, but a sure-fire fix would be to remove the carb and soak it over-night in carburator cleaner, replace it and all should be OK.

2008-04-16 19:09:31 by Thank You