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john deere 318 help, i think the Onan is done for good?

22816 Views 103 Replies 28 Participants Last post by  alfieepstein
New to this forum, and i must say it looks fantastic! lots of helpful people, and lots of great tractor stuff. I bought my "new" 318 in the fall. My first real garden tractor. I searched for quite some time for a machine that could bag vast amounts of leafs, and clear alot of sloped, fairly steep, slippery driveway, and decided on this 318. came with power blower/catcher for leaves and the auger snowblower. It did a great job with the leaves. I was so excited to plow the driveway on this first winter storm in chicago. Well, i tried plowing without the chains, (1st mistake) and the driveway was too slippery, so i went to go get the chains and while doing that, the engine started sounding different, almost like it was on choke. Well, the engine then quit, and now won't start. The starter seems to want to crank it over, but can't so i get a grinding noise. I fear the worst, a siezed engine. There was oil in it, my only concern is that it was parked on a hill for a while, could the oil have drained back leaving no lubrication? is there an oil pump on these Onan engines? I am fairly mechanical, but haven't dealt with tractors too much. Usually if instructed well i can find the problem. my question now is, where do i start? What can i look for to figure out if this engine is done? I'm assuming that since it started ok that it is nothing electrical, and the snow thrower wasn't on and it was in neutral so i don't think its anything related to those two issues. I'm just praying someone with a good knowledge of these machines has seen this before. I don't really want to have to start the post of "so what's the best repower engine" :banghead3 although i'm pretty sure that that is coming.
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Yes i has an oil pump, but you will be pulling the engine to inspect that. Here is a simple check:

Reach under and try to turn the driveshaft a few full revolutions in both directions to possibly loosen it up. See if that works and report back. Take notice how much effort it takes to turn it, as it it should turn freely.
I agree, try turning the shaft by hand, that will tell you alot. Did you hear a bang or any other nosie when the engine quit?? Dumb question, but did you check your fuel level, my 318 really likes its gas when blowing snow and it will just die quite suddenly when out of gas.
There is an oil pump,I doubt the engine is seized,you need to see if the engine will turn ove and you can do that by removing the left side cover and the air cleaner,after you rmove the ac you will see a hole in the flywheel cover,take a long screwdriver and stick in the hole and try turning the fly wheel?If it was running on a hill it might have just flooded the cylinders,remove the plugs and see it will crank over then.These motors are pretty simple so it could not be much.Man you guy's are FAST you got your reply while I was typing mine.Good Luck
Grinding sound, does it sound like the battery is drained at all?
another vote for the battery being low on charge or the battery terminals are not tight on the battery. I had to tap on my battery terminals pretty hard to get them to seat on the battery. As mentioned, take the left panel (the side with the hydraulic controls) off using a 10mm socket (one bolt in the upper top). You can then put you hand behind the fire wall and spin the fly wheel. It has cast blade/fans that are easy to put your fingers on. If it spins freely put some jumper cables on it and try to start it. Don't do the jumper cables before the spin check in case you do have a flooded condition that could bend a connecting rod. I doubt you have a serious condition. The engine would have provided more symptoms as it stopped if this was terminal.
wow, amazing help already, i hope to dive in to some of the possible solutions today. Some i think i can eliminate. about the gas, my first thought walking back to the machine was.....oh my, i hope that thing ran out of gas. So i did check that. however, there are no dumb questions with wouldn't be the first time i missed something obvious. I don't think it's the battery either. I was able to try and crank it over a bunch of times and it seemed very strong. so i believe that the battery is fine. i charged it last night, so i will try again today with a full charge. I pulled the plugs yesterday, hopefully this will shed some light. The plugs seemed to be ok, certainly no mechanical damage. I'm more used to seeing 2 cycle plugs with alot of soot. These were dry, but i figured thats normal, and they had a greyish color which i think seems normal. I did not hear any large bang like a rod blowing through or anything. when it quit. When i was trying to turn it over yesterday, it appeared to me that the flywheel was moving......sounds like a dumb question but i want to be sure, the flywheel should be facing the back of the tractor correct? I can't see any other place it would be as the shaft is on the front. It was difficult to see, but there appeared to be some movement. I guess first things first is to see if the shaft is moving freely, then we can move past the pistons and cylinders. Thank you all so very much, and i will keep you updated.
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i just tried turning it over again, to no avail, did not do the jumper cables, but the charger said the battery was at full charge, i think i see what is the flywheel, but i can't see the fins as it has a cover over it. Am i looking in the right spot or do i need to get farther in? When i cranked it, that cage did spin, but i don't know for sure that that was the flywheel spinning. i did try moving it by hand, but with no fins to grab i couldnt move it at all. To try and move that flywheel should i pull the plugs to eliminate compression? finally where would be a good place to grab the driveshaft to test that?
Here's a pic of the flywheel. (This is the rear of the engine) The engine is out of the tractor and the shroud (cover) is off, but this is what you want to turn. No need to pull the plugs, the flywheel should turn with them in place without problem.


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If you take the fender deck off, where the driveshaft connects to the Hydro pump, would be a good place.
If the CAGE moved it is turning over,DO you know how to check the plugs to see if they are fireing,if so do that and if there is fire check for fuel to the carb.I did not see if it is B43 or P218,we will need to know that next.Yours still has the screen over the flywheel so you get to the fins except through the hole i referred to in my first post.
OK, starting to breathe a sigh of relief. It appears to be turning over. The shroud is spinning pretty good when i turn the key, and i could watch the teeth move inside that hole in the air cabin. I tested the spark, and got spark on both sides. So here's where I am at. It died while running, i have spark, it seems to be turning over. I am still having a horrible grinding noise when i try to start it. I have the 218 engine. I'm assuming to get to the carb, you will want me to pull off the whole air intake cabin. Before i get into that though, do you think it would be related to the new noise that is going on when i try to start it? Seems at this point if its turning over something else has to be locking up or be stuck at startup? although i don't how anything electrical would have killed the engine while running if i am getting spark. BTW, it has the 50th anniversary badge on the side, can anybody get me the year of this model by that? thanks again.
Check fuel. Pull the fuel line from the carb and point it into a container. Try to start the engine. Does gas flow consistently into the container while the engine spins? Also, check for cylinder movement. Pull the plug/s and shine a light into the spark plug hole/s while cranking the engine. Do you see movement of each cylinder?
It would not be model year,hasen"t been that many years since the first one,someone's wife OR husband must have given it as a 50 th wedding present? You will have to pull the complete breather off.
try the reserve versus 'on' for the fuel selector, you may have lost your primary fuel pickup hose in the tank
Don't worry about the flywheel, climb underneath and grab that driveshaft and turn it both ways to see what the engine is doing. Also, just because it says your battery is charged it doesn't mean it is any good or strong enough to start it.
autozone will load test your battery for free (and your starter, actually)
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