I have a Craftsman LTX1000 lawn tractor. I think it is about 7-8 years old. I bought it used this year and am having a throttling issue. (engine: Briggs & Stratton Small Engine Model 407777/0121-E3 20HP OHV I/C Intek Platinum).
When throttling engine to full it only runs about 1/3 power. When I take cover off to access air filter the carburetor shaft is exposed and the engine speed cranks back up. I can run the engine at low throttle and even half choked but when I go to full choke and full throttle there is very little change. There is no way it will actually cut grass. I have tried everything I know how to do:
- Suspected bad gas so drained and refilled
- Changed the oil
- Replaced the air filter
- Removed the muffler to see if there was build up of soot. There was none. I even ran engine with muffler off and still had the same issues.
- Checked the throttle cables. They are moving freely. No broken springs or anything.
- Cleaned all the fuel lines
- Replaced the fuel filter
- Sprayed carb cleaner into carburetor shaft and even removed top plate near carburetor (head gasket?) and cleaned that. I am not sure what this was but it had a gasket and several cavities
- Replaced the spark plugs and checked gap (.040). This helped as the engine cranks much better.
- Tried running with gas cap off in case the small hole was clogged. No difference.
One other strange thing I have noticed since I had the mower. Every time it gets to the last bit of gas before running out the engine suddenly runs really high for about 15 seconds before running completely out. It did it again today - was trying to fix it when it suddenly started running great only to find out it just ran out of gas.
Any ideas? I am about as far as you can get from being a mechanic and I am about to pull what hair I have remaining out my head! Please help!
When throttling engine to full it only runs about 1/3 power. When I take cover off to access air filter the carburetor shaft is exposed and the engine speed cranks back up. I can run the engine at low throttle and even half choked but when I go to full choke and full throttle there is very little change. There is no way it will actually cut grass. I have tried everything I know how to do:
- Suspected bad gas so drained and refilled
- Changed the oil
- Replaced the air filter
- Removed the muffler to see if there was build up of soot. There was none. I even ran engine with muffler off and still had the same issues.
- Checked the throttle cables. They are moving freely. No broken springs or anything.
- Cleaned all the fuel lines
- Replaced the fuel filter
- Sprayed carb cleaner into carburetor shaft and even removed top plate near carburetor (head gasket?) and cleaned that. I am not sure what this was but it had a gasket and several cavities
- Replaced the spark plugs and checked gap (.040). This helped as the engine cranks much better.
- Tried running with gas cap off in case the small hole was clogged. No difference.
One other strange thing I have noticed since I had the mower. Every time it gets to the last bit of gas before running out the engine suddenly runs really high for about 15 seconds before running completely out. It did it again today - was trying to fix it when it suddenly started running great only to find out it just ran out of gas.
Any ideas? I am about as far as you can get from being a mechanic and I am about to pull what hair I have remaining out my head! Please help!
