Help needed with JD 318

[KDOregon]

I sent my John Deere 318 to a local dealer for service after a winter in the barn. After 3 trips back, the tractor is all but unusable. At full throttle, once the PTO is engaged on a slight incline, the unit backfires and sputters to no end. The only way it will operate at all is at a slow crawl at 1/3 throttle max. I am at my wits end - the dealer says they ran 3 tanks of gas thru it, after tuning it the first time. HELP!!! /forums/images/graemlins/confused.gif

 

[Cliff_Johns]

Sounds like the choke is stuck. Not that this is, in any sense, my area of expertise.
Cliff.

 

[rvtech]

Not knowing if it is point ignition or electronic, I would guess it could be point adjustment, or possibly carburetor adjustment.

 

[gunmaker]

Try checking the float and needle valve in the carburator. You shound be able to drop the bowl, inspect the float, range of motion, dirt in bowl, signs of varnish etc.. Remove it make sure it still floats /forums/images/graemlins/smirk.gif Check the needle valve, is it stuck in position, or does it move freely in and out (if it is free it generally drops out with the float), check the tip of the needle valve, some have a rubber or polymer tip that gets gummy or sticky, clean all and replace.
Other items to check; carb settings, check and reset to factory; fuel filter could be clogged causing fuel starvation; check fuel lines for signs of deterioration and or collapsing; check air filter for restriction of air flow.
Hope it helps, if not I may still have a service manual for the 318. /forums/images/graemlins/grin.gif

 

[Toolguy]

If your dealer can't fix it it is probably because his techs are too young to be familiar with it. If you are going to work on it yourself you can get all of the parts you will need from an Onan engine dealer. You will save a lot of money on parts that way. Onan engines are very popular and used extensively for motorhome generators. Otherwise take it to a shop that services all makes of lawnmowers. They should not have a problem getting it to run right. I have a 318 with about 1300 hours. It has been a good machine. The only problem I had was a stuck valve that got smacked by one of the pistons and bent. I fixed it myself with Onan parts. They had all the parts I needed in stock. The dealer would have had to order most of them. Good luck.