Any small engine mechanics on the forum?? LONG STORY!!

[Bob Weisner]

Hi:

This question is for anyone who is a small engine mechanic. I started up my 11 year old 12 hp MTD lawn tractor today (6th time I ran it this year), and everything was running fine. I was pulling a 12 cu. ft. wagon to haul some crushed stone that I was shoveling off of the lawn after the winter snowplowing. I loaded up the wagon and started the tractor. Everything was fine until I backed up into the driveway to dump the stone in the driveway. When I backed up the tractor, I went about 8 to 10 feet and then the engine made this LOUD RACING SOUND!!! This noise lasted for no more that 3 to 5 seconds and then the motor quit!! I tried starting the tractor again. No go. I then took the cover off of the air filter and removed the air filter. I pulled the choke open (As usual), and turned the key. Then engine would start , but only when I had the throttle wide open. After it started, the power was about 20 % of normal. I brought the choke down to normal operating position and the engine speeded up to about 25 to 30 % of normal RPM. The engine will run for no more than 30 seconds. Here are the other symptoms:

1. Backfires. LOUD!!!!

2. White smoke comes out of the air filter chute or whatever it is called when I had the cover and air filter removed.

3. Local hardware engine mechanic thought it might have been just the spark plug. he changed the spark plug, but it did the same thing.

4. New gas in the gas tank. about a quarter inch from being full.

The local mechanic thought that it might be a head gasket or something wrong with the valves..

Any suggestions????:confused: :confused:

Thanks,

[Steve Clardy]

Hmmm. Maybe broke the key on the flywheel?
Maybe got diesel instead of gasoline? [Just checking. Stuff happens]

[Chuck Wintle]

Hi:

This question is for anyone who is a small engine mechanic. I started up my 11 year old 12 hp MTD lawn tractor today (6th time I ran it this year), and everything was running fine. I was pulling a 12 cu. ft. wagon to haul some crushed stone that I was shoveling off of the lawn after the winter snowplowing. I loaded up the wagon and started the tractor. Everything was fine until I backed up into the driveway to dump the stone in the driveway. When I backed up the tractor, I went about 8 to 10 feet and then the engine made this LOUD RACING SOUND!!! This noise lasted for no more that 3 to 5 seconds and then the motor quit!! I tried starting the tractor again. No go. I then took the cover off of the air filter and removed the air filter. I pulled the choke open (As usual), and turned the key. Then engine would start , but only when I had the throttle wide open. After it started, the power was about 20 % of normal. I brought the choke down to normal operating position and the engine speeded up to about 25 to 30 % of normal RPM. The engine will run for no more than 30 seconds. Here are the other symptoms:

1. Backfires. LOUD!!!!

2. White smoke comes out of the air filter chute or whatever it is called when I had the cover and air filter removed.

3. Local hardware engine mechanic thought it might have been just the spark plug. he changed the spark plug, but it did the same thing.

4. New gas in the gas tank. about a quarter inch from being full.

The local mechanic thought that it might be a head gasket or something wrong with the valves..

Any suggestions????:confused: :confused:

Thanks,
it sounds like it may be a stuck valve. when one sticks, engine compression is lost, backfiring occurs with loss of power. It is probably easy to pull the head and have a look see.

[Bob Weisner]

Update on the Old MTD tractor:

Well, Good news and bad news:o

1. Had the tractor picked up by the small engine mechanic and he had it for almost a week. :confused: Thought I was in for a BIG BILL:eek:

2. He called with the diagnosis: He said that the compression was good! Battery just needed a slight charge because it had not been running since last Fall.

3. Replaced the old inline fuel filter with a new clear see thru fuel filter. Installed a new spark plug. Adjusted the carburator. Found out the carburator was LOADED with RUST!!. Cleaned out the carburator. Ignition swith would not turn off. Found rust on the ignition coil. Replaced ignition coil and cleaned rust off of the ignition switch.

4. Checked for mouse nest in front fins. Found nothing. Emptied gas tank out and cleaned gas tank. Refilled gas tank.

5. Adjusted and tightened tractor seat.

6. Fixed the linkage(whatever it is called) , that keeps the blade belt from turning the mower blade when not engaged.

7. Refilled front tire and replaced the air nozzle thingy(whatever it is called) because it was rotted out.

Delivered and test ran it.

Total cost: Just a little under $140.00.

[Paul Downes]

I WAS going to suggest that it sounded like the engine got leaned out-not enough fuel for the air. Hence a carb problem. But it sounds like it's under control. Now git mowin!