KT725-3055 Smoking Badly

M

Mike's lawn

Forum Newbie
Hi all,
I've A Cub Cadet 46" cut with a KT725-3055. I just replaced the carb with no problem. I have started it a couple of times. Today I went to start it to try to mow. The engine would not turn over. I grabbed a wrench and pulled the motor through a couple of times. Tried to start it again, this time it started but started to blow serious smoke and oil out of the exhaust.
I'm open to ideas as to what has happened?
Thanks
--Mike
 
You may have had a hydro lock. If the carb leaks, it can get enough fuel in the cylinder that it won't turn over. Pull the dipstick and smell it. Does it smell like fuel? If so, change the oil. Some advise to change it several times, after each mow when it has been hydrolocked. I would recommend a cut off valve on the fuel line to prevent this. There are multiple ways to test for the leakage. Hook a transparent line to the carb, fill it with fuel and mark the spot. See if maintains that level for 1/2 hour or so. There are also pressure testers available.

This can be caused by dirty fuel. Check your fuel jugs, and the flow from tank to carb. It should flow reasonably freely. I also put a filter between the tank and carb, along with the shutoff.
 
Hydro lock was definitely a problem. Changed oil, a couple of times. I have replaced the carb, hoses, and fuel pump. Runs great when first started . However after it warms up it starts to sputter, backfire and keeps dying. Ideas please! Could I be losing the 'coils'? I have replaced the plugs as well.
--Mike
 
First, if you hydro locked after changing the carb, the carb could have a problem. If the hydro lock was caused by the previous carb, fine, but if it was the new one, you need to address that. A simple way to test is with a transparent fuel line attached to the carb, with the other end held elevated. Mark the fuel level and see if it stays there. If it leaks, drop the bowl, remove the float and make sure the needle and seat are clean. This isn't the best test, but it's a start.

While doing this stuff, make sure you get a free flow from the tank through the line to the carb. Crud in the fuel tank can restrict the flow inconsistently.

I like to pull the plug, connect it, ground it, and crank the engine. You may need some shade, but should see the spark.

If the motor runs, then dies and won't start, try this after it dies, and see how the spark looks. That should let you know if it's a spark problem.

What kind of carb did you get? I'm suspicious it's the problem.
 
Sounds like the "new" carburetor has a bad needle and seat if that is what introduced this problem. You need a better carburetor or carefully rebuild your original with a new kit.

If oil is over full, it has gas in it. Drain it out and change with new. If it has an oil filter change it also. Run it for 15 minutes to clear out the muffler and the engine no longer smokes.
Change the oil again to make sure all of the fuel is eliminated out of the crankcase.
 
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