My Tractor Forum banner

1 - 20 of 133 Posts

·
Registered
Joined
·
148 Posts
Discussion Starter #1
Hi:

Went out to cut the lawn, started right up with a bit of choke, smoked a bit (which is not abnormal). Got 1/4 way around the lawn and she died. Tried restarting to no avail. Lots of gas in it. Oil level was right on full when I started out. Checked the plug and it was pretty black and oily looking. cleaned it up and tried to spark test it and it's firing at the plug when I turn it over fine. I sprayed some gas into the carb after removing the breather. Still no go.

If it's the seat/safety switch causing it, would it still spark at the plug? Do these switches fail often? I checked the points, they look pretty good. I used a bit of fine sand paper to clean the points anyway and retightened the cover. Still no go.

Suggestions?

thx.
 

·
Registered
Joined
·
113 Posts
Did you happen to get the points gap correct? Might be worth a check. On my wheel horse with the 8 hp kohler i had a similar issue. Mine ended up being the amp meter believe it or not. I just hooked my two amp meter wires together temporarily until i could get another meter.
 

·
Registered
Joined
·
148 Posts
Discussion Starter #3
If I'm getting spark at the plug when I turn it over, that should mean it's getting fire correctly...no? Do the points just go out-of-whack sometimes? This would cause the firing to occur at the wrong time?
 

·
Moderator
Joined
·
4,138 Posts
You need fuel, spark and compression....I would do a leak down or compression test...that oil on the plug could be an indication that the rings are shot
 

·
Registered
Joined
·
113 Posts
I would start with the points or spark plug. The points are kind of a way of timing the k series ive been told (might be wrong). Its possible they've worn down a little. Could also be the spark plug. If i remember correctly is .020 is the gap for the points.
 

·
Registered
Joined
·
148 Posts
Discussion Starter #6
I do have a new set of rings, head gasket, cylinder hone, feeler guages and a ring compressor. just waiting for the oil pan gasket so I can put it back together once this undertaking begins. I was hoping to make it thru the season before having to do this...oh the joy....
 

·
Moderator
Joined
·
4,138 Posts
I do have a new set of rings, head gasket, cylinder hone, feeler guages and a ring compressor. just waiting for the oil pan gasket so I can put it back together once this undertaking begins. I was hoping to make it thru the season before having to do this...oh the joy....
So you saw this coming?...or did you order the rebuild stuff after it stopped running?....if you are doing all that you should probably go for it and replace and lap the valves too

Since you have spark, I don't think points or timing is a problem, but here is an excellent video showing how to set them
 

·
Registered
Joined
·
148 Posts
Discussion Starter #8
I bought it a few months back. didn't pay a lot for it. didn't expect it to be 100%. I ordered the kit once I saw the amount of smoke
the engine was emitting. What do you recommend tool wise to cut the valve seats?
 

·
Premium Member
Joined
·
269 Posts
First thing I would do is take a jumper wire from the POS on the battery to the POS on the coil. You may see spark at the plug, but is it enough to fire the fuel??? Anytime Where the engine just died, about half the time it's the ignition switch. If it starts with the jumper wire, start with the ignition switch and then clean all the wiring connections.
 

·
Premium Member
Joined
·
269 Posts

·
Registered
Joined
·
148 Posts
Discussion Starter #11 (Edited)
The previous owner somewhere along the line put a craftsman starter key switch in...

RE: putting a wire going from the POS battery terminal to the coil, what gauge wire is needed to jumper it for a start test? So, do I just connect it to the positive side of the battery terminal and then hold it onto the positive coil side when I try
starting it or do I tie it directly to the coil on the post? This rules out the starter switch then...correct?

I'm in PEI Canada btw...long way from kansas. ;)
 

·
Registered
Joined
·
148 Posts
Discussion Starter #12
Should you be able to see the piston move in the cylinder with the plug out when cranking the engine? ie: is the piston directly under the plug?
 

·
Moderator
Joined
·
4,138 Posts
I would just lap the valves...I would not cut the seats...although if I had a lot of engines to do it would justify buying that tool...looks like it does a good job......just need lap compound and the suction cup tool...less than 10 dollars....when the engine is cranking you should see the piston moving if you have removed a plug...I would disconnect the battery first...remove plug and if you cannot see into the cylinder, but a screwdriver in and slowly turn the flywheel and see if the screwdriver starts riding back and forth with the piston...if the piston is not moving, you have thrown a rod

To do the "jump" test you can use jumper cables...if you do not have them #10 wire with clips on the end will be fine for the test
 

·
Registered
Joined
·
1,477 Posts
I think I'd take a lok at the air cleaner too... if it's really dirty it might be restricting the air flow to the point the engine is flooding. I'd also try a new sparkplug as often a really dirty one will not make a nice enough spark to start an engine.
 

·
Registered
Joined
·
227 Posts
To answer your question - you saw spark, so spark is good? Maybe - maybe not.

You can have a weak spark that you see when you test it, but under compression it is not enough to run.

Things that can weaken the spark:
1. carbon build up on plug - the carbon allows the spark to travel to ground rather than jump the gap (try a new plug)
2. weak ground (try taking a wire from the coil body to the neg battery terminal). I chased this issue on my 317 for quite awhile - replaced points, cap etc - all for a corroded ground wire.
3. weak voltage to coil (can take a wire from coil to pos battery)
4. bad capacitor (try a new one). A bad cap will often give you spark, but it is weak and short in duration.
5. Bad sparkplug wire. High resistance eats the spark or cracks allow leakage to ground.
6. Bad coil
7. Points? Usually point issues result in no spark or bad timing

...and a bad seat switch would typically mean no spark, but is could reduce the voltage to the coil. Jumping a wire from the coil to bat pos would rule this out.
 

·
Registered
Joined
·
148 Posts
Discussion Starter #17
So, no piston movement when cranking - a thrown rod I assume. That would explain why with spark it isn't starting. Looking like I'm in for a rebuild. Thanks for all the tips/advice.
 

·
Registered
Joined
·
148 Posts
Discussion Starter #18
UPDATE: I talked with isavetractors.com to get their input as to what parts might be needed. I explained that I wasn't "seeing" any piston movement in the cylinder. Norman mentioned that the piston is offset quite a bit from where the spark from the plug hole is. He suggested putting my thumb over the plug hole and turning it over. There definitely is compression. So, it would appear that the crank is in tact (good news!).

To continue troubleshooting, I checked the spark plug gap and it's as per spec (champion H10C). There is definitely fuel getting to the cylinder via the carb so the fuel system (pump) is working. Either something is killing it from a short or the coil is bad I'm guessing. I did put a volt meter on the positive side of the coil yesterday evening and was getting 12V when turning over. I took apart the seat connection underneath, cleaned the contacts and made sure they were seating well. No
change. I then took the ignition plug apart from the connectors and sanded/cleaned the connection pins good. No change.
It does turn over well.

One thing to note, that before I started her yesterday afternoon to mow the lawn, I added fuel. I'm wondering if that fuel might be bad.
 

·
OLD TIRED CDN. MECHANIC
Joined
·
9,024 Posts
Bad fuel will definitely do it ! Simple things first before contemplating the worst.

Just a trick that may help:

With the spark plug out and holding it in a gloved hand, take your propane torch and burn off all the residue on the plug electrode.

Now get that plug rosy hot, then quickly screw it back in, push its' wire back on and try cranking with the key "while the plug is still hot". Sometimes this is just enough to get the engine firing under adverse conditions.
 
1 - 20 of 133 Posts
Top