Just got an old riding mower with a 12.5hp tecumseh engine. The thing starts up okay but wont run for more than a few seconds. I replaced the fuel line and cleaned out the carb and it seemed to run great then but only for about a minute before it died. Afterwards, the airfilter box was full of gas and the muffler was spewing out a mix of things (1st it looked like black motor oil, then it looked like gas) which I dont see as a good thing. When I cleaned out the carb, a little silver washington monument shaped pice fell out of it without me knowing at 1st and I have no idea what this thing is. If its a point, Im stumped because I've never replaced points before. Anyone know whats going on with this thing? :confused:

It could be flooded take the plug out and see if it has spark if no spark the gas is probibly due to excessive priming over time (trying to get it started)

It could also be spark not igniting the gas, I'd also take off the head and see what kind of condition the piston is in. (I have had pistons with large chips out of the side but it didnt affect the piston compression rings so the engine still ran).

any of these can lead to this problem.

Hope this helps.

Fuel inlet needle resembles Washington Monument part you described. It hangs on a small wire hanger between two metal tangs on the float. As fuel fills the bowl, the float rises forcing the needle against the seat(small rubber o-ring in inlet port)which stops fuel from coming in. As engine uses fuel, float sinks causing needle to release from seat allowing fuel to enter bowl and so on. Re-installing the needle should fix your problem.
-Chuck

Okay, I got the needle back in place and it fires up again but its still having that problem. Start it up on full choke "VROOM!" and then it quits before I can take the choke off or anything. Know what it could be? Im still stumped. :drunk: Also, Its not priming itself. I have to dump gas in the airbox to get it to start and after that gas is gone, its dead.

So the gas doesn't run out everywhere? first change the oil, probablly has gas in it...

Secondly..... when you put the float back in, you made sure it was parallel to the carb body? and it moved freely? take the fuel line off at the carb and also make sure gas is getting to it at a good rate.

The oil is new and the float moved freely. I just replaced the battery (old one needed charging every 3 times I tried to start it) and Im still getting nothing out of it. I appreciate the help so far but the problem has yet to be solved lol. Im still trying. Also, I just filled it up about 1/2 way with gas and saw it had gas going into the airbox so I was happy and figued it would start up so I turned the key and got nothing.....Then I looked at the muffler and what do ya know, black motor oil and gasoline (yes, I checked this time...its gas) so I dont know what to do about this thing now.

MMkay, this is weird; I took off the cover for the overhead valve and found a big mess of that junk that was pouring out of the muffler and cleaned all that crap out. After cranking it over a few times by hand, no junk came out. I checked the spark plug, seems fine, sprayed in some engine starting fluid and replaced the spark plug. The fuel line is NOT connected right now and it fired right up and stayed running till I turned the key to "off" and no black, oily, gas junk spewed out of it this time, just a few puffs of white smoke and then nothing. I think I may have solved the problem unless it starts up again. Possibility of a cracked block? Anyway, thanks for the responces! Any ideas of what was going on with it? Please let me know!
Thanks a ton!

NO, no cracked block.....
But if I get that correctly..... you started it up without the fuel line connected to it...... Of course no gas would free flow.....

Thats true, the line hasnt been reconnected yet so lets say its still pouring gas out of the muffler like it was before whenever it starts up. I've never encountered this problem with any engine before so Im still puzzled but I'll start it up in the morning and see if the problem continues. Once again, any ideas on what the problem could be?
Thanks! :dude:

Usually if you have fuel free flowing, its either a stuck float, float full of gas (developed a pinhole and sunk) leaky inlet needle and or seat. (or seat was installed upside down)

Okay, I got it fixed now, it runs really nice now. One problem left. The muffler blows out white smoke when running and when I shut it off it kept smoking like it's going to catch fire or something. This muffler really needs to be changed but the bolts are completely stripped and the craftsman bolt out set somehow didnt help. What could the problem be this time? lol. The problem before was, I didnt have the needle set right but its good to go now. So, what could the smoke be coming from?

Sounds as though there is still oil in the muffler. Use it about ten minutes and see if it clears up.

I'll try that pretty soon, gonna let the storm die down before I go out there again. Thanks for the replies!

Seems okay now. No more smoke out of the muffler, just out of the OHV chamber on the front. Making a crackeling noise too like something's on fire inside it. Aside from that, I cant get it to operate on anything else besides full throttle. Any ideas?

Ok, what you got here is a plugged up Carb, which is running lean, and causing the engine to overheat.

The fact it won't run at anything but full throttle just triggered that for me.

I just went through the same thing.

You're gonna have to pull the carb apart and clean it out with Carb Cleaner. Recommend you get a carb rebuild kit so you have all the gaskets, o-rings, etc... you need.

You need to make sure the tank and lines are flushed out as well, and change the fuel filter if it has one.

-Larry

Alright thanks! :) So after I get the carb rebuilt, it should run ok? The 1st thing I did was drown it in carb cleaner when I got the mower and it looks quite clean in there. The only other question I think I have is, when it was spewing junk out of the muffler, and I found a lot of that junk in the OHV chamber....what was that oily mess and how did it get there? As far as I know, there isnt supposed to be any fluids in that thing. Anyway, thanks again!

I would hope so :)

No guarantee's of course! But a carb kit and a little labor is a small investment.

Here's a hint for you. Take digital pictures. LOTS OF THEM!

When I rebuilt the carb I took almost 200 0f them. A dozen before I even unbolted it from the engine. All angles, as close as possible.

Then I continued taking pictures, 360 deg around, as I took it apart. Step by step, picture by picture.

Especially if carbs are new to you. There's lots of little parts that can turn it into a Rubik's Cube :)

As for the smoke/gunk, I'm just not sure. It's possible due to a lean run it overheated the oil I guess.

It's hard to be positive not being able to see it in person.

-Larry

I've gotten my riding mower fully operational now, puts out some white smoke but I dont know how to fix that. Anyway, the gravity fed carb isnt priming so I have to dump gas into the air cleaner to get it to start every time and since its gravity fed, I dont see why it would do this. Only other problem I can think of with this thing is that it drains the battery awfully quick. Put a new battery in it and left it over night, ignition off and had the key inside the house and the next morning, the battery needed to be charged. Should I get a new ignition system? Also, what should I do about the carb not priming?
Thanks in advance! =D