Kart only getting spark sometimes.

[kartnewbie27e]

I have a Tecumseh 5hp engine that's only getting spark sometimes.

Before it cut off and started acting stupid, it was running fine. Then it just cut off. I tried to start it back up and it acted like it didn't want to turn over. I also noticed that it was a little harder to pull the pull start.


I checked the valve clearance yesterday and I couldn't even get .002 through it. I adjusted both to .004 as I've had them set at that since I got it. Gave it a few more pulls and checked the clearance again and now just the intake is shut again. I adjusted it back and everything seems to be staying at .004, but still no start.

I checked for spark, and the first time I checked, it had spark. The next time and everytime after that, no spark.

Any ideas?

 

[OzFab]

Check the gap between the coil & flywheel magnet & also the kill wire from the coil to the body (the green wire); if it's earthing, that will kill the spark

 

[kartnewbie27e]

Check the gap between the coil & flywheel magnet & also the kill wire from the coil to the body (the green wire); if it's earthing, that will kill the spark

10-4 I noticed a little rust on the coil last time I was messing with it. I'll see if I can get that off.

 

[mckutzy]

Light sanding by hand would take care of that.
Also, depending on the age/condition of the motor, the spark wire may be damaged or broken somewhere.

 

[Doc Sprocket]

Generally speaking, rust on the magneto armature and related parts won't cause a problem. Cleaning it win't hurt, but it's not likely the issue.

When you have an intermittent spark, it is tough to troubleshoot, but the ignition systems are so simple, it shouldn't be too hard to nail down.

Begin by removing all the tinwork on the engine and examining the wiring for nicks and pinches where the wiring passes the tinwork.

If your engine has a breaker points system, you will have to remove the flywheel to inspect. I once had a briggs 8hp that was giving me fits because the wire to the points was being pinched behind the points cover. While you're at it, make sure the points are correctly gapped (usually 0.020") and cleaned. A new condenser may be an idea.

As a test, you can also detach the kill wire completely, and attempt to run the engine.

Examine the spark plug wire insulation for cracks. If you find any, wrap the entire length of the wire with 2-3 layers of electrical tape.

 

[kartnewbie27e]

Ok, I'm getting consistent spark now, but still no start. It has fuel, air, and spark. It also has compression.

The only thing different is that it feels different when I go to pull start it. I don't really know how to explain the feeling, but it feels weaker? Usually when you try to start a working engine, you hear it kind of sputter out of the exhaust, but there's not really any sound when I pull it. Just the feeling of compression. Which is weird.

Any thoughts?

 

[Poboy kartman]

Check the flywheel shear key....

 

[rocketkart]

Install a new spark plug gapped at .030 and is usually a champion J8 or equal!
You can gap the plug at .025. It may run little better when the gap is changed. the valve clearance should be, Intake should be .005in - .007in and Exhaust .008in - .010in.

 

[kartnewbie27e]

Check the flywheel shear key....

Gonna go out to eat, then I'll check it. But if I remember correctly, the I can see the crank spinning just as fast as I pulled it, so I'm pretty sure the flywheel is atttched.

 

[rocketkart]

that doesn't mean anything. it may have sheard the key and the flywheel my have slipped off timing.

 

[kartnewbie27e]

Was checking out the flywheel and noticed the starter cup was loose, so I tightened that up and got it to idle for 3-5 seconds. Tried to start it up again, and it's catching better and acts like it wants to start, but still doesn't. I sparyed a little carb spray in it, but still nothing.

Checked the air filter and that's in good shape. Also, the flywheel is right where it's supposed to be.

Good news is that I'm gonna pick up my predator 212 tomorrow

 

[kartnewbie27e]

Install a new spark plug gapped at .030 and is usually a champion J8 or equal!
You can gap the plug at .025. It may run little better when the gap is changed. the valve clearance should be, Intake should be .005in - .007in and Exhaust .008in - .010in.

Here is the valve clearance chart for tecumseh engines. Mine is the 5th from the bottom. OHH50. Says .004 on intake and exhaust, so that's what I set it to.

 

[kartnewbie27e]

Just pulled the sprak plug again to see what it looked like after I got it to idle for a few secs earlier, and there's a little bit of oil on it. Just a tiny bit.

 

[Poboy kartman]

Was checking out the flywheel and noticed the starter cup was loose, so I tightened that up and got it to idle for 3-5 seconds. Tried to start it up again, and it's catching better

That makes me even more suspicious that the key is damaged. ......

 

[rocketkart]

That makes me even more suspicious that the key is damaged. ......

 

[landuse]

Yup. Check the key

 

[Scout]

I wouldn't be surprised if it was flooded.

 

[zbuck]

I wouldn't be surprised if it was flooded.

Me too, pull the spark plug, ground the spark plug wire and turn the engine over 4/5 times to clear the cyl of gas, install new plug gapped @ .030 and see what happens.