I have an 86 deere 318 with 640 hours. It has always been a rough start, but last week, the starter stopped working completely. When I turn the key, it just spins, and doesn't enage the flywheel. I've already done a bunch of reading and after ruling out the other possibilities, I'm thinking (actually hoping) the starter bendix needs cleaning and lubing. Well, My question is, how do I get to the bendix? Is it difficuly to reach? I'm hoping this fixes the issue because I hear replacing a starter on the 318s is a PITA...and expensive. Honestly, I love this tractor, but I'm thinking it may be time to trade her in for something newer and more reliable.
Hello XJbone
Since your 318 is a Model made in 1986 it
could have one of Two Onan's that they used back then. The earlier 318's had
a B-43 Engine. This style engine has Point's & Condensor Ignition. The later Onan was
the P-218 or often called The Performer-18 engine. These engines had Five cubic inches more than the older B-43's they were 48 Cubic inch and they had
the New Electronic style ignitions. The
starter's used in these two different engines differed as well. The B-43 Engine had it's starter solenoid in the steering tower of the machine under The Battery Box. The
P-218's had a Bendix style solenoid Mounted right on top of the starter. The earlier B-43's had very Little starter issues unless their starter drive gear got worn, they were Problem Free. The P-218's have alway's had hard start issues so
John Deere offered a Starter Improvement kit for them. The Kit cost's about $40.00. It allows a full 12-Volt current to be delivered to the starter when it is engauged to start the engine. This Kit By-Passes The Machine safety switches Thus allowing a Full 12-Volt current to the start when starting the machine. Most P-218 Onan Onwer's have Placed this Starter Improvement kit on their 318's and it solved all of their starting issues.
If you have the Older B-34 engine
they do Not require this starter Improvement kit. Before Pulling the engine I would suggest that you check the
wiring Harnes Safety swich connections. Given the year of the tracor it is Not uncommon to see some of the connector's with corrosion. We Must remember that the starting circuit
has to Travel though all of the machine's Safety switches when you turn the key switch into the start Mode. Look at The Seat switch connector, Hydro lever Neutral safety switch, PTO connector swictch which is on the back side of the Dash Panel. I would be willing to bet that there is corrosion at one of these switches preventing a full current of 12-Volt's from getting to the starter. Also Pull The Ignition switch Plug off the back of the switch and check for corrosion. You can buy some
electrical contact Grease at any of the auto aupply stores, so I would suggest you get some and place it on the safety switch connector's before pulling the engine. Onan does not suggest any Grease on their starter drives, it only atracts Dirt and dust.
Now come the hard part
trying to find out Just what engine you have. After 1985 John Deere replaced the earlier B-43's with a Performer P-218 engine. In doing so, many simply used The Blower Housing sheet metal, Point's & Condensor, along with the Older style B-43 engine, Placing all of these Part's over onto a P-218 Block. The driveshaft for a B-43 engine differ's from the P-218 driveshaft as well as it is about 1-1/2" In length shorter due to the different flywheel's used on the more modern P-218's, But if a dealer was looking to keep the cost down
he could use the B-43 sheet metal Blower housing, Poiint's & condensor, Flywheel and drive shaft that went to the B-43 as they bolt right up to the P-218 Block. 
In trying to figure out just what engine that you have here you will have to see
just what Starter that it has by Looking down in there. If you look from the front of the Tractor you should be able to see if it has
a Bendix drive about the starter. If there is No Bendix drive on it, chances are that it is a B-43 Starter, But
this is still Not conclusive as they used all of the outer engine component's from my B-43 When they Installed the new P-218. The Two different starter's bolt up differently was well.
The B-43 engine starter bolt's up to The Oil Pan of the engine, where as the
P-218 starter bolt's directly to the Left cylinder Head.
Now for The Bad Part... To
service these starter's the Engine has to come out of the Tractor. It is Not as Bad as it sounds though... You will have to Unbolt the Four engine bolt's underneath the engine. You will Then have to remove the floor pan by Taking out The Four bolt's that hold it in place. You will Then have to remove the battery and it's Battery holder from inside the steering Pedestal. Once the Battery and it's Tray have been removed, you will have to Un-hook the Hydro Transmission drive shaft. There will be Five 5/16" Bolt's that hold it to The engine crankshaft, Take them out. You will Not have to remove the drive shaft, so Just let it hang there. Now you will have to remove The Hot Cable to the starter. It can be taken off from the front with a Long 3/8" Ratchet extension. Remove the ground cable from the engine, as well as the choke and Throttle cables. The last step is to Unhook the wiring harness to the engine. It will be a Three wire plug that is close to The engine coil. The electric PTO clutch connector will have to be un-plugged as well. Now you should be able to Lift the engine out of the Tractor frame.
Once it is out, you will have to remove the blower Housing sheet metal on the side where the starter is so that you can get to The starter bolts. Un-bolt the starter and either
have it re-built or replace it. Be Sure when you put The new starter on that it has
the correct gap between the Starter drive gear and the flywheel Gear teeth. Onan say's the correct Lash for this should be between 0.015-0.20" of an Inch. If the Lash is excessive you will have to drill One hole in the starter to allow it to be moved closer to The fly wheel. Use a 21/64" drill Bit to do this and I suggest that you use a drill press to get it straight not off center. Once the hole in the starter has been made, you can place it on your engine and swing the starter enough now to get The required gear lash. I set mine to 0.16" and it performs flawlessly. I hope this helps, if you have
any problem's Just PM here and I will Help you through them.
I would Not consider getting rid of your 318 Just over a Starter issue as the 318's are as Tough as a Brahma Bull... 