Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Hi,

My recently bought (second hand) Ariens ST504 won't start anymore. It used to be really easy to start. Throttle on 50%, full choke and three pushes on the primer and it would start on one or two pulls. It was the neighbor who drove it the last time so I don't know how it acted last time it ran but the neighbor didn't mention anything until he tried to start it next time.

Anyway, now it won't start no matter what. There's fresh petrol in the tank (maybe a bit too much). I've tried having the lid off the petrol tank when starting but that didn't help. The spark plug gets oily after I tried starting a couple of times and after cleaning it I can get it to *almost* start. A few puffs of pretty black smoke and then it dies. Then, the spark plug is all oily again. I checked that there is a spark and it seems fine. Probably time for a spark plug change but it seems wierd that it died so suddenly, no? 

When pushing the primer, it sounds and smells like fuel gets through but I don't know how to check the fuel line better. I haven't starting taking the covers off to check the eninge more but I was hoping to get some pointers before doing that.

So, any ideas?

/Ola, Sweden

Now I'm at a loss.

Today, I get no spark. Tried both the new and the old spark plug and nothing. So I checked with a "spark checker", whatever those are called. The kind of lamp you connect between the spark plug and the spark plug wire. I tried it before and it worked but today I get nothing from it.

I checked for electrical connections and got a bit confused:

The black wire that comes out from under the pull-start cover and that connects to the black lead to the ignition switch is always grounded. Should it really be like that? I thought setting the ignition to "off" grounded that wire by connecting it to ground via the red lead from the ignition switch. I.e. ignition off = black wire from under the cover, via the black wire to the ignition and then to ground via the red wire. Turning the key breaks the grounding via the red wire and the engine can start. Am I wrong here?

If I'm right, what do I do about this? Sounds like  it's time to take it to a professional because new electrical parts isn't readily available here. Also, since everything is under three layers of cover, I don't even know where the coil and magneto is located on this engine. Or maybe it's just a case of corrosion and I should try to repair it myself. If so, what are the steps I should take?

This thing is really haunted... Now it seems like I've managed to break my spark test lamp. So there *may* a spark. However, I can see no spark from the spark plug when I take it out, ground the tip against the engine top and then pull the starter cord. Maybe it's a so much fainter spark than the one from a car that it can't be seen with the naked eye.

Should I be able to see a spark when grounding the tip of the spark plug and pull the start cord?

Should the wire coming out from under the start cord be grounded all the time?

No answers to these two questions?

ofranzen wrote:

You should be able to see a spark.  The wire from under the flywheel shroud should NOT be grounded all the time - if it is, you have no spark due to the ignition coil being grounded!

Marty

Thanks for your replies Marty

So there's something grounding the coil all the time then. Any ideas on typical spots to check for corrosion or other problems? The ignition system is terribly well hidden but I'm guessing that taking the entire engine apart is the next step in getting this running.

Accessing the coil should be easy if the engine doesn't have points & condensor. Once the starter housing (flywheel shroud) is removed (only 4 or 5 bolts need to be removed), it should be right there in plain sight. If it is, remove the little wire going FROM the coil to your shutoff switch. NOW check for spark. If you have no spark, the coil is bad. If you get spark after removing the wire, then that wire is shorting to ground somewhere or the switch near the throttle is grounded - also make sure the metal carb cover isn't touching the shutoff lead that the throttle touches when it's in the off position.

Marty

I finally found the problem!

I took the flywheel off and checked the point gap, condeser, coil continunity and that there were no shorts and I could not find anything wrong. Then as I was sitting there looking at the crankshaft and the flywheel and realized that the key that keeps the flywheel and rankshaft in place and saw that it was sheared in two...

That's why I could get it running for a while on idle - the timing was just a bit off then. Then I got no spark at all - because with all the start attempts I had moved the igniton timing too much off and got no spark at all.

So, I took the larger of the pieces and jammed it to hold the flywheel in place temporarily and now I got a spark.

Finally...

Now I just have to get a new flywheel key. Thanks for all your help.

/Ola

/Ola - good job! A sheared flywheel is not very common on a snowblower engine - glad you found it & got it buttoned up!

Marty

Now what...? I swear this engine is out to break my spirit...

I got the flywheel key and installed it. Checked and cleaned the magnets and coil core and checked the gap. Checked coil continuity, capacitor, cleaned the points and checked the gap. I could easily get a spark just by turning the flywheel by hand so I assembeled the engine to try it out. After assembly I checked if I still had a spark and sure, nice and strong and the kill switch worked.

So, I primed the engine and pulled the starter a couple of times. Third try or so I got a cough and then nothing. Checked for spark. Nothing. Changed spark plug and checked the gap. Nothing...

So now I have to take everything apart again and I'm *really* close to just tossing the darn thing into the pond....

Why did I loose the spark? What should I check?

Please help me again.

/Ola