Small engine repair

[BoberFett]

I have a lawn mower that's about 10 years old but sat unused for about four years. It was always a hard starter, from the time I bought it took some priming and several pulls to get it running. When I first tried to start it after pulling it from storage, it wouldn't start at all. I did some basic cheap stuff that I thought might help but so far it's a no go. I replaced the air filter, the fuel line, the spark plug, and even pulled the cylinder head off to make sure there was nothing nesting in there. When I remove the air filter and spray some carb & choke cleaner in the thing, it will run for a few seconds then sputter out.

This leads me to believe maybe the carb is just too badly gummed up and needs to be replaced. Before I start ordering new parts which I imagine might not be cheap for an older model, anybody have any other ideas? Can I just pull the carb off and soak it in something for a few days to attempt cleaning it?

 

[natto fire]

Yeah, you can pull the carb off disassemble and clean the jet(s). Make sure to remember how everything goes back together (or take a picture). There are also lots of books that can be loaned from the library that can help you with this. Probably not going to be worth the cost of another carb, but that largely depends on which carb your motor uses. I am going to go out on a limb and guess it is a 3.5hp Briggs and Stratton engine?

 

[kevinthenerd]

This sounds like old gas. The stuff turns into a varnish-like substance when the lighter molecules evaporate off first leaving the heavier molecules. (Gasoline is really made up of lots of different hydrocarbons.) It ran on carb cleaner because carb cleaner is combustible. (I've seen car engines with no gas run temporarily on carb cleaner.)

Find some way to clean it all out. Watch the carb cleaner on plastics, though. Carb cleaner might attack your carburetor diaphragm, so don't go crazy until it's all taken apart and you can be sure it's acting on metals.

 

[spidey07]

me! me! me!

I just went through the same thing. You're carb jet is clogged.

dissasemble the carb and the jets (you can find exploded diagrams on the net) and soak in diesel fuel. Clean the carb and spray carb cleaner in every hole you can find. Wear eye protection when you do. I had to clean my main jet out with strands of heavy duty copper wire after being soaked (this was preventing fuel from entering the throttle body). You're problem is you are not getting fuel.

You're all set. Make sure to drain all the gas out of the fuel lines as well.

Found my old thread.
http://forums.anandtech.com/messageview...atid=38&threadid=2028303&enterthread=y

She started right up after I cleaned the main jet (the tube/nozzle that dips down into the fuel in the resovoir). Once I got fuel into the throttle body, all is good.

 

[olds]

Did you replace the fuel?

 

[BoberFett]

Cpt Howdy - It's actually a Craftsman mower with a 4.5 Tecumseh

kevin - That's probably what it is. I don't think it was drained properly before storage and there was fuel still in the lines. I pulled things apart enough to know that if it is indeed a fuel problem, it's probably the carb. I just wasn't sure if it was worth either tearing it apart or buying a new carb until I got a second opinion.

spidey - I thought something like that might be the issue, I just thought it was odd that it would run briefly with the carb cleaner. I'm far from being an engine guy, but I have pulled apart the carb on my motorcycle to switch jets and improve performance from the factory setup so I'm sorta familiar with what's inside a carb.

olds - Yes, I replaced the fuel. That was the first thing I did, that and change the oil.

Thanks for all the advice, maybe I'll dive into it and pull it apart tomorrow.

 

[WHAMPOM]

Go to gardenweb.com and find the forum on push mowers, they will tell you all about Tecumseh.

 

[slag]

your main jet is in the threaded brass screw that holds your float bowl on. Clean it thoroughly. There are 2 very very tiny holes that are probably gummed up. If that doesn't do it for you, throw the carb away and buy another off ebay. Those eager-1 carbs (if thats what it is), are notoriously hard to rebuild much like the carbs on the honda hr* series of mowers.

 

[skyking]

Originally posted by: slag
your main jet is in the threaded brass screw that holds your float bowl on. Clean it thoroughly. There are 2 very very tiny holes that are probably gummed up. If that doesn't do it for you, throw the carb away and buy another off ebay. Those eager-1 carbs (if thats what it is), are notoriously hard to rebuild much like the carbs on the honda hr* series of mowers.

It is probably the jet in the cap as you mentioned. It is so small, it is best cleaned with 1 wire pulled out of stranded speaker wire.

 

[Toastedlightly]

for the lazy.. once you get it running, add a little seafoam into the tank (recommended mixing is on the package). The should clean out any remaining gunk that may have formed on the valves and stuff.

 

[kevinthenerd]

God I hate Tecumseh carburetors. I had that exact mower before I moved out of my last house. When I had a B&S mower, I'd work on the carb if it needed it. When you have a Tecumseh carburetor and you care more about just getting it over with, rather than spending a half an hour or more just playing with lots of little parts just to get it apart and back together, get a new one.

 

[kevinthenerd]

If you have random chemicals laying around like I do, adding acetone to the fuel will also do an ok job cleaning it all out.

Edit: Seafoam was probably the better suggestion.

 

[xanis]

SeaFoam Deep Creep. Spray some of that stuff in your engine and you're golden. My friend used it on his lawnmower and '77 Trans Am and they both run like champs.