tractor engine cranks but doesnt ignite; whats wrong?

Question

please read here for details on what happened to my tractor:
http://answers.yahoo.com/question/index;_ylt=Apx6SOHsf8iJdEmseYMQ7dLsy6IX?qid=20070619140903AAnAsCy

i topped off the oil, took out the spark plug and cranked the engine a few times. ok. i put the spark plug back in and cranked it - no ignition. when the engine is cranking fast, i can hear excessive vibration. i know this is not good.
but at least the engine is not seized...

that excessive vibration really bothers me. its so loud i almost dont want to touch it. it sounds like something big is clanging around inside the block.

Answer 1

EpicRacer,
I have kept up with your questions through the evening and now there is no doubt. The connecting rod is broken, thats what is clanking around inside the engine. Sorry to be the one to break this news to you, but there is no way around it now. A new short block or complete engine is the only remedy for this machine. If you will include the model and type numbers I will try to find whether you can get a short block if one is produced by the factory, or if a complete engine is your only option.
Either way it would be best to tell Dad now what has happened before he finds it on his own and gets more mad for not being informed.

Answer 2

If you don't know if you shut it down, then it probably died on it's own. you say you changed the oil last Sept., oil viscosity breaks down, plus most engine, especially small engines, burn oil. It gets passed the piston rings, into the combustion chamber, and burns off. You didn't even check the oil when you first took it out for this new season. That is a must, and your father should have taught you this.

It sounds pretty bad, and the least costly thing would be a stuck valve. the head of the engine would have to come off though.

Check for compression; remove the spark plug, put you thumb over the hole,( NOT IN IT), and turn it over. It should push your thumb away. If it does, it's probably flooded, BUT, if it don't, you have severe engine damage. The least of which would be the stuck valve, the worst is a broken connecting rod, or some other moving part.

EDIT
I didn't see your edit until after I wrote the first part. You broke something bad.
Lesson to all engines, If it don't sound right , don't rev it, especially without a load on it, like in neutral.

Answer 3

When an engine cranks and won't start there are only two basic things that can be wrong. It either has no, or improper fuel, or no or improperly timed spark.
Check to see if you have spark. Check to see if you have fuel.
If either ar missing, you then find out why it isn't available.
Lack of spark on an old coil and distributor system can be caused by a bad capacitor, a bad coil, incorrectly adjusted points, bad wiring, bad distributor cap.
Fuel? probably a bad fuel pump. Assuming you have gas in the tank. Water in the fuel?
If both components are available, you should get some kind of ignition and operation even if poor. If nothing fires, then at least one of the components is not functioning at all.

Answer 4

If it its a mowing tractor then it has a switch on the seat that has to be activated. Seat on it!! It could have another switch in the neutral position of the gear level. any or both of these switches must be "ON" to unground the magneto that produces the spark that will start your engine. If not spark, it will turn and turn until the battery goes down. The excessive vibration might be because the clutch to the blade could be also engaged and some manufacturers put a safety switch there also. The idea is that to start the engine first you must be seated properly, the transmission is in neutral and the blades must not be engaged. Then you engaged the blades and put the gear in forward to start mowing. Before I forget, some manufacturers also put a switch on the brake pedal to make sure that your foot is there. All these switches are wired in series. Got it?

Answer 5

I think that you broke the connecting rod. Remove the spark plug, have someone crank the engine over while you hold your thumb over the spark plug hole. If it does not "blow air around your thumb you have no compression which could be caused by a broken connecting rod.

Answer 6

If the engine won't crank over - it particularly does not count while you're turning out to be spark and gasoline or no longer. examine all the battery cables - grounds, starter connection, etc - examine for 12 volts from the starter housing to the starter solenoid collectively as somebody holds the foremost interior the crank place. If it is there, replace the starter - if it is not there, worry shoot the ignition swap, impartial or seize swap etc.

Answer 7

At this point, it would take someone to look at it to be able to tell you what is wrong with it.

If you scored the engine (metal friction grinding into the cylinder walls) then you would see smoke, usually it's white. If you scored it then the cylinder pressure would drop and you wouldn't be able to get the thing to turn over. If you have the tools check your cylinder compression. If you have no compression then your problem is what's called "blow by" in which your power is simply directed elsewhere besides the piston. Compression is required to make the needed amount of force to push the cylinder down.

Answer 8

could be spark plug or the fuel pump