Lawn Mower Help
 

help, my lawn mower is acting up!

started to mow today, and got ~5 min into it when it started to act as tho it was starved for fuel.

it started fine as always and after running great for several passes, it wanted to stall. in fact, i had to stop it since it would not cut out alone. it will continue(every time) to start strong and maintain for about 10 seconds before struggling to stay on.

just a little background and history...

fairly new spark plug
burns oil, so the plug and air filter(also fairly new) were cleaned and re-oiled respectively, after this issue started to no avail
oil level is fine
took the muffler off w/ same result
it is ~9 years old
carb connection is fine(my edger had starting issues because the carb hose was not fully engaged)

i do not want to take it to a mower shop(too much $$$), that's why i'm asking for your help. i'll sooner buy the reel mower i've been wanting.

i thought carb, but why does it start and stay strong for a short time, every time?

thoughts?

Sounds like fuel starvation. Check fuel filter, water in the gas/a piece of floating rust/crud blocking the main jet.

Does the carb have a float bowl? If so, remove it and see what's in there. Sounds like the gas is trickling in slower than the engine is burning it. When it dies, enough trickles into the bowl to get it full enough to immediately start again.

Also look in the tank to see if floating crud is blocking the tank outlet (where gas enters the line to the carb).

Another thought- loosen the gas cap and see if it runs better- if the cap is not venting right a vacuum can develop that keeps gas from flowing to the carb.

if the problem is water in the tank (and you suspect that it is) you can put some alcohol (IPA) in the tank and stirr it up. it will run like crap until the alcohol gets out of it but it should run the water through it.

Also check the choke. It may be sticking.

Since there's a lawnmower thread going already, I'd like to add my lawnmower question to it. If you don't care about my long background story, scroll down to find the actual question.

Background: I'm a complete idiot when it comes to lawnmowers, as I have use a reel mower for most of the time I've lived in his house (my lawn is about 10% larger than a postage stamp). Before this place, we lived in apartments. (As a kid, I was trusted to use the mower, but never to maintain it).

So, I have this 3rd hand mower I know next to nothing about. I was told it needed a new spark plug, but it would start if you used starter fluid with it. It worked fine for a season (with starter fluid), then I bought a reel mower (see above) when it ran out of gas. Now we are about to move, before selling this house, and I'd like to get the old mower going again, to minimize the time and effort required to maintain the old place, since I'm going to have to care for two houses at once (and I don't have a Pickup, so I don't want to be hauling a mower back and forth). I replaced the sparkplug a few days ago, but I haven't put any gas in it yet, because I need to know:

The actual question: How do I tell if I need to mix oil with the gas, and how much to use if I do? Also, can I just use stanard (or synthetic) motor oil for a car, or do I need to buy special lawn-mower oil? I have a couple of individual quarts of miscellaneous oil leftover from buying cases, so I figured if wouldn't cause serious problems, I'd just use that. (Not that I'll need two quarts for a couple gallons of gas, right?).

Also, do lawnmowers have oil that isn't mixed in to the gas? How often do you need to change that?

Here's the only other piece of info I have about the mower: It's a Murray.

P.S. Feel free to laugh at me for being completely ignorant of this stuff... :D

The first thing I thought of was a clogged air filter, but you said it has a new one. Have you tried starting it with the air filter removed? One way to find out if it is the fuel system or not is start it and when it starts to run rough spray some carb cleaner into the carb if it comes back running strong you'll know it's in the fuel system. It sounds like trash or water in the carb not letting it get the fuel it needs to run smoothly. I'd take the carb off and disassemble and clean it good with carb cleaner. If there's water in the gas you'll be able to tell when you take the bowl off of the carb.

If it's a Murray it most likely has a Briggs & Stratton 4 stroke which means it wouldn't need the gas and oil mixed. Also if it has an oil sump it doesn't need oil in the gas because that is what the oil in the gas does in a 2 stroke keeps the motor lubricated. Most lawn mower manufactures recommend using straight 30 weight motor oil. Multi viscosity motor oils will cause them to use more oil. Most push type mowers with 3-4 HP engines hold about 20 oz of motor oil and the recommended change interval is 25 hours or at the end of the season whichever comes first.

it does sound and act just that way. but, what do you do with an auto choke?

Erik, Beef, and Ford Man,

thanks, i'll try looking @ the carb and fuel. not being good w/ this type of thing, if i tear the carb apart and can't get it back together, the new reel mower search will be on!

ok, just took the air filter off and put the throttle wide open...

i could see the throttle moving back and forth by itself w/out the filter before i manually "got on it."