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Rototiller starter cord retracts violently

Posted by dottyinduncan z8b coastal BC (My Page) on
Sun, Apr 15, 12 at 11:47

We have an old Ariens Rototiller that is generally in good condition. It was just returned from anual servicing but came back with new problems. The scariest is that when I pull the starter cord, every once in a while it is tugged back into the mechanism very suddenly and violently. It didn't start. Yesterday, I thought I had broken a finger when it did this. The cord is in good condition. Now I'm afraid to even try to start the machine until I know it is fixed properly. Any suggestions about what I should do?


Follow-Up Postings:

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RE: Rototiller starter cord retracts violently

Sounds like a kick-back from being out of time. The eng fires too soon and tries to make the eng run backwards. That is usually painful! If the eng was just serviced, I would suggest you take it back "soon" and report this. loger


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RE: Rototiller starter cord retracts violently

Also, make sure the engine is on the compression stroke before yanking on the rope. But, like Loger said if it was just serviced take it back.


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RE: Rototiller starter cord retracts violently

sheared flywheel key?


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RE: Rototiller starter cord retracts violently

Agree with Andy!


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RE: Rototiller starter cord retracts violently

Thank you so much! I had our handyman trying to tell me that it just needed a shot of WD40. The repair shop told me they just worked on the carburetor, not the starting mechanism so they are not responsible. I know what you are saying is correct because of the violence of the cord retraction. It had to be mechanical. I will be back to them tomorrow.


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RE: Rototiller starter cord retracts violently

A sheared key would throw the timing but I feel lack of proper flywheel torquing could have caused this if it was just services. Does this motor use a steel key which I would think vs my old B&S? This would lead me to not proper torque again. When I see “old” and if it has points vs electronic ignition, could a bad point setting be the problem and assist in damaging a key due to a kick-back?? Back to the shop is the Bottom Line, unless that is a problem. loger


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RE: Rototiller starter cord retracts violently

Was the tiller used from the time of the recent service and this issue? If so, did you come upon any sudden resistance that basically stopped the engine instantly? Which is not common compared to a lawn mower hitting a stump etc. Aluminum keys vs steel are basically a safety feature to reduce damage or breakage as well as aligning timing. It will be interesting to hear what they find and possibly why. loger


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RE: Rototiller starter cord retracts violently

I appreciate the continued discussion. This problem began immediately and has happened twice. The tiller hasn't been used anywhere where it could hit a snag. Interestingly, once it starts it runs ok but differently than it used to. It sort of coughs once it warms up but it keeps running. The invoice says he changed spark plug and air filter, checked operation and set carb. Check gear ease seems to be ok, put on new air filter. Used 30 w oil.Because it seems to run differently, I think the timing is off but sorry, I'm not at all mechanical. I really want to sound at least a little knowledgeable when I talk to the service people tomorrow. Thanks again.


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RE: Rototiller starter cord retracts violently

Well, continuing frustration. Just talked to the shop owner and he tells me there is nothing wrong with the timing because it doesn't do this all of the time. His story is that it worked fine in the shop and they weren't asked to fix the starter that there was nothing wrong with!!! He says that they will replace the starter but of course there will be additional charges. I don't mind paying for work to be done but I don't have confidence in these people any more. He also said "don't go looking on the internet for problem solving".


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RE: Rototiller starter cord retracts violently

  • Posted by baymee LehighValleyPA (My Page) on
    Mon, Apr 16, 12 at 15:39

He also said "don't go looking on the internet for problem solving".

True, alot of the time. But the advice you've been given here is professional.

Replacing the starter won't solve your problem. If you don't pull through the compression stroke, it's possible that a spark ignites the gas but the engine goes backward and rips the rope out of your hands. Slowly bring the engine, with the rope, to a point where you feel resistance and then pull harder. Out of time usually produces kick back all the time. Sounds to me like you aren't pulling hard enough.


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RE: Rototiller starter cord retracts violently

I have an old troy bilt horse that will do the same thing. I think some of the older engines without some type of compression release and a smaller radius on the crank pulley are worse to kick. I make sure mine is on the compression stroke and pull like heck, or use the electric starter which is 110 volts and a little unhandy.

Larry


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RE: Rototiller starter cord retracts violently

I believe that the advice I have received here IS professional and that the serviceman I spoke to is not professional. At the very least it gives me an idea about what to ask for. I absolutely hate these pull starts, they are so difficult and now I'm scared of it. I'll get my handyman to tell me about compression strokes. Thanks again. Slowpoke, what do you mean by: "use the electric starter which is 110 volts and a little unhandy?"


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RE: Rototiller starter cord retracts violently

Some snow blowers are equipped with 110V starters, but I'm not aware of them being used elsewhere.
IF you didn't experience this problem before and do now, then something is definitely amiss.

The spark timing is controlled by the flywheel.
The flywheel has a magnet in it. When it rapidly passes by the coil (transformer basically), the magnetic field induces an electrical field that is stepped up by the coil.
When the voltage reaches a certain point, it jumps the spark plug gap producing a spark.

IF the flywheel key is sheared (sometimes they break "slightly" and then jam the flywheel preventing it from rotating further) the spark occurs at a different time than it's supposed to.
Typically they shear because the engine came to an abrupt stop and the HEAVY flywheel wants to continue to rotate. The key shears and the flywheel (with magnet) rotates a bit more. The magnet now comes by the coil that much sooner and fires prematurely in relation to the piston stroke.

Basically, the spark plug is supposed to fire just as the piston has reached the top of its stroke and is starting to head down. Spark plug fires, combustion and the expanding gases push the piston down producing power.

With the spark occurring prematurely, the piston is still coming up to the top of the stroke, spark occurs and the piston is driven back the way it was coming. OUCH!


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RE: Rototiller starter cord retracts violently

  • Posted by baymee LehighValleyPA (My Page) on
    Tue, Apr 17, 12 at 5:41

I have the same kickback with my Troy horse (Cast iron 6HP Tecumseh) and I know it's because I'm serious enough in my pulling.

Over the years, I've had mowers with severe kickback that wouldn't start at all. The key was only moved a few thousands of an inch. I've had mowers that start up and run rough and the key is sheared and moved an inch away from its normal position. So, there is no rhyme or reason here.

I've seen a sheared key on a big Cub Lawn Tractor because the flywheel nut came loose. But in your case, it doesn't seem like the shop did anything wrong. I would specifically ask the shop if they removed the flywheel to check the points, if there are any.


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RE: Rototiller starter cord retracts violently

baymee, Very good info. Could a recent carbon build-up cause this or add to this? I would agree that the key and points need inspecting if points are present. A Tecumseh has always been a killer because of the good power (due to better timing tolerance IMO vs a B&S that will time w/o an effort). loger


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RE: Rototiller starter cord retracts violently

Dotty, I have an old 7 hp Tecumseh engine on my horse. Someone before me installer an electric start on it. The started motor in 110 volts rather than the standard 12 volts that most use. I don't need a battery for it, I just plug an extension cord into a receptacle on the engine and press a button, unplug the cord and I am ready to go. The started works very well but you have to have household current to operate the started. you will have to have a flywheel with teeth on it to use a 12 or 110 volt starter.

I love the fact that I don't have to fool with a battery. I just keep a 100' extension cord plugged in and drag it over to the tiller if I don't want to crank it. It only takes 1 or 2 pulls to start the tiller, but if it kicks it feels like it is ripping fingers off.

Larry


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RE: Rototiller starter cord retracts violently

  • Posted by exmar 6 SE Ohio (My Page) on
    Tue, Apr 17, 12 at 14:03

As always, excellent information here. dotty mentions "old" without telling us how old. Most of you would consider me "old" but I'm still firing on all cylinders....:-)

Couple of things bother me, if the tiller is "old" then the owners would be used to it's starting idocyncracies (sp?) and the sudden kickback seems new. The group opinion is that this is a timing issue, and I agree. If the "service" outfit doesn't recognize that, it's time to find another outfit. Also, replacing a flywheel key isn't major surgery for a "service" outfit. There's also the fact that in changing a plug, air filter, and setting the carb, it is highly unlikely that the timing was changed or degraded.

So, it would seem there's still more to the story, or the flywheel key was previously partially sheared and decided to move "just enough" to cause this timing issue coincidentally to the yearly service. I know I've had engines that were running fine and "suddenly" started acting up without hitting any major bumps or obstacles and it was the flywheel key. Cheap fix.

Good luck,

Ev


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RE: Rototiller starter cord retracts violently

  • Posted by baymee LehighValleyPA (My Page) on
    Wed, Apr 18, 12 at 5:29

Carbon buildup would increase compression and make the engine more difficult to pullstart. We could also be looking at a coincidental occurrence of kickback. Key question is if they pulled the flywheel for any reason.


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RE: Rototiller starter cord retracts violently

IMO I think the big question here? Do the machine have points? Did the recent routine service provided required the points to be replaced or checked? IF so they had to remove the flywheel to get to the points to either inspect them or replace them. Now the flywheel key could be factory or the engine tune-up was degraded from lack of preventive maintenance that it wouldn't kick back.

IMO I would first think the owner didn't pull it up to the compression stroke before attempting to start as stated. Usually older tiller engines don't have the compression to kick back due to lack of maintenance (oil changes, points plugs and decarborizing) I dought it in the key unless they tampered with the points and left it loose. I dought they went that far into the ROUTINE servicing. IMO That's how they probably know it wasn't them casuing the problem cause it starts fine for them when they pull it up to the compression stroke and are strong enough to pull it pass the next compression stroke..


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RE: Rototiller starter cord retracts violently

  • Posted by baymee LehighValleyPA (My Page) on
    Wed, Apr 18, 12 at 19:44

""That's how they probably know it wasn't them casuing the problem cause it starts fine for them when they pull it up to the compression stroke and are strong enough to pull it pass the next compression stroke..""

My opinion too. As a strong man, I can start almost any mower with one pull. For an older woman, it can be a whole different story. So, knowing that, I usually don't let mowers out of the shop unless they can be started reasonably easy.

Sometimes this means a little more work on the carb, primer, or whatever. Since I have about 800 customers on my list, I can pretty quickly weed out a sheared key issue from another kickback cause.


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