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Discussion Starter #1
Ok trying to fix a JD 314 with Kohler k301 seems to have spark just wont fire even using either! Tries to start but wont, I am usually pretty good at figuring out things but I am stumped, my next thought is to check key in flywheel to see if sheered as the 314 is driveshaft driven off of flywheel maybe it sheered and timing off. Any thoughts or Ideas.......
 

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If you have good fuel and good spark,,the only thing stopping it from running is compression. ACR hasn't got anything to do with it. It opens the valve a split second early ,and only for a split second to assist in starting.

Timing could be an issue but seems it would still run just not very pretty.lol It,s worth checking the key,,for sure,,but its a long shot.

Does the spark look strong?? How hard is it roll over by hand?? Is there any resistance.
 

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Discussion Starter #5
yes spark is very strong(fat blue) turns over very easy with plug out (using starter) once plug is in there is a noticable drag if you would call it that on starter and again there is enough crank speed to start it. Questioning the person who was driving the mower when it quit said it just stopped got it started again but only for a moment? Found the sight hole on my wheel horse for timing mark so I suppose it would be in same spot on the deere but I guess there are 2 spots for timing marks and sight holes? I will use the ohm meter test to see where the timing mark is once points start to open hopefully it is just points out of adjustment but I would think it would still start nonetheless although beit rough. As the flywheel runs a driveshaft still thinking may have sheered the key but that will be the last thing I will check as that requires the removal of the engine
 

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Sounds most likely it is the key to me.If your spark plug is firing at any time except your compression stroke it won't run because you need to compress the air fuel mixture to create the explosion in the combustion chamber and you can't do that if either your exhaust or intake valve is open.If it is the key make sure you tighten the flywheel bolt to the correct torque or you'll just shear the key again.I've had that problem on a few engines and it sounds like it wants to fire but just won't.
 

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Discussion Starter #7
Flash 5153 it has good vaccum so I think it should also have good compression and valves seem to be both cycling(looking through spark plug hole for exhaust and carb throat for intake) crude but the best I can do at this time. If this were my engine it would be on the bench already! but this is kinda freebee job so I need to diagnose without too much labor
 

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On second thought the flywheel key has nothing to do with the timing if you have a coil and points setup.I believe timing is achieved from the pushrod that pushes the points open.The flywheel position would only matter if you had a magneto setup.Correct me if I am wrong.
 

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I'm thinking the key could be sheared now too. I would think this would one of the first things to check,,easiest,,but OK.

Does it have a mowing deck installed?? Take a look at the blades and see if one is bent badly. Or maybe you know if something stressed the engine.
 

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Discussion Starter #11
On second thought the flywheel key has nothing to do with the timing if you have a coil and points setup.I believe timing is achieved from the pushrod that pushes the points open.The flywheel position would only matter if you had a magneto setup.Correct me if I am wrong.
Yes you are correct never thought about it that way now I am back to square one and need to do a compression test I guess as I dont think points could be out that far but maybe!
 

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Discussion Starter #12
I'm thinking the key could be sheared now too. I would think this would one of the first things to check,,easiest,,but OK.

Does it have a mowing deck installed?? Take a look at the blades and see if one is bent badly. Or maybe you know if something stressed the engine.
Arniearni was right the points actuator is cam driven so if the key was sheered it would not effect the timimg
 

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Yep, on Kohler K series, the flywheel Key only serves to hold the flywheel in place on the crank for, if anything, dynamic balance purposes, Timing is cam driven.

If it were me, Id do a quick simple test..put some WD40 in the cylinder, maybe a few capfulls of motor oil..and put the plug in, spark plug wire on...and crank the engine. While its cranking, looks for vapor spitting out around the head gasket, looks for puffs of smoke or vapor, a dribble of oil...if its blown and on the exposed sections of head..you should see it. If its under the blower shroud, you wont see it.

Kohler K's were notorious for blowing head gaskets, rendered them, many times, very difficult, or impossible to start.
 

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Discussion Starter #15 (Edited)
Well I went over and did the whole gig set points gapped plug same thing wont fire, dosent feel like has much if any compression, wont pop my finger off hole or even make a pop so now what ? can the ACR mess up and cause this or is it a bent valve or broken ring? guess I am going to pull the engine and then the head to check valves and cylinder walls as I cant remove the tin without removing engine. I dont know what else to do. Head gasket maybe but we have never seen anything blowing out and everything looks dry at least what we can see but possible. Like I said before if it were mine it would have been out and on the bench already Thanks for the info red 85 z51
 

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You can pull the head without removing the engine, easy.

Remove the tin over he head, should be 2 bolts holding it on, then remove all the head bolts, then lift off the head.

If there is a valve problem, the tell tale is to remove the plug wire and crank the engine over with the plug installed and feel over the muffler..air should ONLY come out, not suck in... and inversely, the carb should suck in and not blow out. If thats all good, the valves are good to go.
 

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With the plug out, when you crank it, do you feel air blowing out if you put your hand over the plug hole?

If not...you have a broken connecting rod or piston crown seperation...

If you do..carry on with the previous course of action.
 

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There is nothing been suggested here that requires the engine to be on a bench. You need to get methodical about diagnosing this. First you said it has compression, then not. Eliminate the simplest thing before moving on.
 

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Discussion Starter #19
I put my finger over the hole it will not pop it off but I stuck a plastic plug in the hole and it pops it out with a good snap so I dont really know if compression is good especially with the ACR I just dont know how much compression is lost due to its action. I will try the hand over the muffler test maybe this will narrow it down a bit
 

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It should blow your finger off with a fairly violent force, with a sharp POP.
 
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