Help with cub cadet 1250
 

I was given a cub cadet 1250 that 4 other people couldn't get to run right. It will run on idle just fine. But when you go full throttle it will run rough and blow white smoke from the exhaust. It has a kohler 12hp engine. I cleaned the walboro carb on it with brake cleaner and compressed air. I was going to change gas due to it sitting for awhile and I seen water in the gas from the bowl on the carb. My next step is to check the points. Any other suggestions?

Well first I would change that gas, especially if you see water in it.
White smoke in cars is usually water, the same would apply here.
Probably why it idles fine is that the gas will float on top of the water, but when you run at higher rpms, the gas and water in the float bowl of the carb will start to mix, and water will also get into the engine.

Since you said this mower has been sitting, you would want to pull of the outer metal pieces of the engine to clean all the fins, or at least check all of them. Having any nests, debris, dirt, etc. will cause problems later down the road, usually in the form of the engine getting too hot in that location.

If you cleaned the carb with brake cleaner, you have to watch the seals. Brake cleaner cleans well, well enough to harm the few seals in the carb. The rebuild kits are cheap, and you may want to do it anyway while you have it apart. I just had to redo mine because the seal for the float needle was leaking, and I was losing gas.

I would say check the points, clean them if they need.
Make sure you have fresh, properly filled oil in the engine.
These are very simple engines, just make sure they are clean, inside and out, and have oil and you should have very few problems.

But really, get fresh gas before trying to figure out any other problems.
I've ran through a tank of bad gas in a car once, it was difficult to really pin point the problem. No point in working with multiple problems at once when you can fix one and move on to the next one.
In the plastic tank, there is also a screen, you will want to make sure that is clean so the engine can get all the fuel it needs when its running. You will also want to get the gas/water out of the fuel hose and the carb bowl.

Sorry, I can't think of anything else to really check first, but if I missed something, hopefully someone else will post more advice.

Fresh gas with a touch of Marvel Mystery Oil or something is the FIRST thing I would do. Nothing worse these days than gas that has been sitting in your gas tank for weeks or months, etc.

My second thing would be to swap out that Walbro Carb for a Kohler Carb.

Disassemble the carburetor, soak it in carburetor cleaner overnight blow all the passages out, make sure the high speed needle is clean between the upper and lower holes. Put a kit in it, install and adjust as described in the manual.

Clean the points and adjust the timing as outlined in the tech section.

You may also need to sand the head flat, clean the carbon off the top of the engine and piston and install a new head gasket. Do not install a new head gasket without sanding the head flat.

And yes, get rid of the watered down crappy gas.

Use snake oil in the gas if you want or not... I have no opinion on additives.

I just picked up a 1450 and a 1200 Wednesday that haven't run in awhile and will be doing the same things to them this weekend.

Making them run and run right isn't all that hard.

Thanks for the tips. I'll be changing gas this weekend and checking the points. Then further troubleshooting if those things don't fix it

White smoke in cars means water from the cooling system. Water in fuel will not run. It can, if it mixes enough to run, cause a backfire, but otherwise it would just not run. Remember, gas floats on water, and the carb pulls from the bottom of the bowl. If the bowl has water in it, it WILL NOT run at all. White smoke on this engine does not mean water in the fuel. Same does not apply at all, the engine is air cooled. White smoke is likely not really white in this case, unless the fuel is just junk, or has some kind of additive in it. It is likely oil that has crept into the engine from non use, and the fact that the rings will likely have to reseat. New fuel and some run time and most likely it will go away.

Drain and clean your fuel system. Come on, if you see water in it, that's a given. Follow Yosemite Sam's advice and you'll be fine.

X-2, and it'll be runnin:beerchug: