[Grass_disaster]

i recently fixed the governor on my mower.

it died on me recently.

it has 75 compression in both cylinders.

it seem to die like it was runniing out of gas not it wont start. when i was trying to get it going it would backfire. it probably backfired 8 times while trying to start it.

it no longer back fires while i crank it over. it crankes over ok but just is not firing.

any ideas? where to start?

timing problem fuel broken parts? have no idea.

it makes a slight grr sound once the starter is disengaged. before it was kinda locking up it seemed on the compression stroke but then id release starter and crank again it would crank fine.

 

[chuckv]

Ryan,

Which engine is in your 318, the B43 or the P218? Your profile does not list the year of your tractor -- hence the question.

If it is a later model with the 218 and electronic ignition, the 'backfiring' and non-starting could indeed be timing off due to the trigger rotor slipping time on the crankshaft.

It should be kept in place on the extension of the flywheel key, but they have been known to get out of orientation. Your problem could also be a failed electronic ignition module itself. You will need to pull the flywheel to access either the rotor or the module.

Here is a picture of the rotor as well...if you replace the module, replace the rotor at the same time.

Parts can be obtained at your Cummins/Onan dealer a bit less expensively than through Deere.

Let us know if your engine is the earlier B43 series, as that is a different set of timing issues with the points ignition.

Chuck

 

[Grass_disaster]

well i have electronic ignition>

please let me know what steps i should take to diagnose this

 

[chuckv]

Ryan,

Do you have any spark at all? Remember that the plugs are IN SERIES on these engines and that the wire of the plug that you are not testing should be grounded while you are looking for spark at the other one. There is a procedure in the TM1590 on testing/troubleshooting the ignition system, and that is the best place to start. If you don't yet have this very important manual you can get it on CD at your dealer or from our site sponsor Keeping It Green for about $50.

I can e-mail you some info to start...and below is the ignition diagram.

Chuck

 

[Grass_disaster]

i'm going to take a guess that its something to do with that plastic part you showed me.

 

[chuckv]

Ryan,

Because access to the rotor and ignition module is only gained by removing the engine from the tractor and then pulling the flywheel, it makes sense to verify that you have a hot spark at the plug before removing the engine. If you do not, perhaps there is some other electrical gremlin in the safety circuits that is causing the lack of ignition.

Use a voltmeter to verify that you have 12 volts on the + side of the coil when the key switch is in the RUN position and while cranking also. Verify also that you have a good engine ground connection, since you recently pulled the engine to do the governor work. Keep us posted on what you find...

Chuck

 

[Grass_disaster]

yes good idea i'll check it out and let you know if i have 12volts.

i havent looked at it but are the wires easy to access to test. i'm not sure what wires to test i guess.... maybe i'll figure it out if i look at it.

 

[Tony_geneseo]

ryan & chuck ,
this only a question-clould it just the compression is just too low ? electronic ignition should be the 218 right ? my 218 has 120 in both cylinders. maybe thats still enough compression to run. i know on 1 of my walkers the compression just dropped too low to even fire thats why im asking. just an idea... good luck tony

 

[chuckv]

Tony,

The manual lists the minimum compression at 75 PSI -- so Ryan's engine should run OK even though it may be getting closer to needing rings and a valve job.

Chuck

 

[Grass_disaster]

well i didnt get a voltmeter but i did check for spark and both sides seem to have good spark.

i just pulled them and held them on the block.

 

[chuckv]

If you are sure that the fuel is getting into the carb (even try pouring a sip or two directly in...) and you have compression and spark then the remaining issue most likely is timing -- sorry.

Time to pull the engine and take the flywheel off and have a look...

Chuck

 

[Grass_disaster]

yes i tried the fuel trick earlier with no avail.

i can smell the fuel too when i try cranking it over. so i'm pretty sure its getting fuel.

 

[khe]

What is the condition of the fuel pickup in the fuel tank? It may be possible the pickup hose has rotted off and even though there is fuel in the tank, there may not be fuel reaching the carb.
You can pour a small amount of gas into the carb. and then see if it will start. Don't pour in too much or you run the risk of hydrolocking the engine.

 

[Grass_disaster]

well the key way was broke. the one that holds the flywheel in place.

so that was a easy diagnosis.

wonder why it broke? did i not have it tight enough? pretty sure i torqued it down. i was thinking of taking a little emery cloth to the shaft to make sure it doesnt want to spin.

afeter jd told me they had the part on hand. i drove 20miles to the dealership only for them to dell me sorry we dont have that one. they were nice enough to pay for the part and have it shiped to my door free of charge. thought that was ok of them. i should have the part in 4 days or so.

 

[Grass_disaster]

it was part # he515-0284 so i hope thats right, kind od a bad picture

 

[chuckv]

Ryan,

Yes, HE515-285 is the correct part number for the half-moon key with the extended "tail" to engage the rotor for the electronic ignition.

DO NOT rough up the tapers!! The flywheel internal taper and the taper on the crankshaft must be VERY clean when you assemble them so the surfaces can mate closely enough to transmit the torque to/from the flywheel as the engine compresses the fuel charge then fires it. When you think about it, this is occurring 3600 times a second for a two cylinder engine... The key is for alignment purposes and is not meant to transmit the angular momentum involved.

Chuck

 

[Grass_disaster]

figured you would say that.

wonder why it broke.

what is the purpose of the grey bushing? if i remember the key fit inside of it.

the bushing seems to be in good shape.

 

[chuckv]

Ryan,

The gray plastic circular part in the picture in my post 4236 above is not a bushing. It is the rotor that contains a strong magnet which triggers the electronic ignition module at the correct point once per crankshaft revolution. The extension of the flywheel key is what engages the notch on the gray rotor ring to keep it in the proper angular alignment (i.e. in "time") with the crank. When the key broke, the ring could rotate relative to the crank such the spark was no longer in correct the timing, hence the starting issue that began this thread...

Chuck

 

[Grass_disaster]

NOT GOOD. I FEEL LOST.

got the part put it in perfectly, plastic part with flywheel out..out everything looked great.

STILL WONT START.

it was backfiring when i would release the starter(with it non choked, not like that matters).

iw would backfire some or it would "fluf" out the carberator...puff of white smoke out the top or it would backfire.

i dont think it was the pin. i tightened the flywheel down a lot for it not to spin again.

i'm ready to take it in somewhere. pretty disgusted at this point.

 

[chuckv]

Ryan,

The engine will sometimes 'backfire' if the key is released just at the time that the compression stroke is under way. This happens because the voltage to the ignition coil is being removed and the field in the coil collapses, causing a spark voltage at the plugs (just like the field normally and intentionally collapses when the points are opened on the older b series engines, and of course the electronic ignition module does the same function in your P series engine's case...) This is not an indication of being out of "time", but rather that the electronic ignition module most likely has failed. In one of your earlier posts you indicated that you had good spark when cranking the engine -- is that now no longer the case??

Do this test: take out both spark plugs and ground the wires to them so that you don't get 'bitten' by a spark voltage. Slowly turn the engine over by hand and see if the voltage at the (-) side of the coil is being taken to ground at some point of the engine's rotation. If this is not the case (or if it is always at ground, i.e. zero volts and never jumps up to 12 volts...) then the module is bad.

Sorry to be the bearer of bad news, but you will need to pull the flywheel AND the stator to get to this module, as shown in the red oval in the photo in my post #4236 above...

Chuck