# Briggs kickback



## Buster (Feb 18, 2004)

Hi,

I recently put a newer Briggs motor onto a rototiller. Same style motor as original. It has a magneto with 3.5 hp. 
I put a cast iron flywheel on to counterbalance it. I installed a new flywheel key.
This motor had a kickback problem before and it still has even after changing the flywheel.

It runs great otherwise. Any ideas?


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## hankster (Jan 1, 1998)

In the vast majority of cases it is a timing issue. Could be the wrong flywheel, a sheared flywheel key or even a twisted crank.


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## Buster (Feb 18, 2004)

Hi Hankster,

How do I find out if it is a twisted crankshaft without ripping it down?
I put in a new key and tried both flywheels. Can you run me by the steps to set the gap on the Magneto (no points)?

Thks 
Dave [email protected]


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## hankster (Jan 1, 1998)

I'm more of a 2-cycle guy and would rather one of the 4-cycle experts give the proper way to do it.


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## dgraham225 (Dec 6, 2002)

the easiest way to set the flywheel is take a business card or something similar thickness and put it in b/w the flywheel and coil. tighten it down there and roll the flywheel over to get the card out. 

as for the flywheel, what was wrong with the original aluminum one?


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## Buster (Feb 18, 2004)

This motor was off a lawn mower. Because I put it onto a tiller the cutting blade was no longer required. This meant replacing the flywheel with a heavier one (cast iron) to counterbalance the engine. Previously the blade provided the counterbalance.

How can I determine if the crank is twisted or bent?


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## dgraham225 (Dec 6, 2002)

oh, i didnt see that it was a lawnmower. even still, i had a 3.5horse that came with the aluminum flywheel.

as for determining if the crank is bent, i dont see how it could be really. i have never seen that problem personally. it may happen, but i dont think its likely. im stumped on this one.


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## repair_guy (May 9, 2004)

That's a new one for me.I've never run into that problem before,could it be that since a lawnmower blade being lose can cause a kick-back,And your castiorn flywheel is playing the part of the blade now that your castiorn flywheel is not perfectly balanced?????????


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## Buster (Feb 18, 2004)

I had the kickback with the original aluminum flywheel and it is still there with the cast iron one.

I set the timing by adjusting the magnetron gap to spec. I am stumped too?


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## hankster (Jan 1, 1998)

Buster, You mighyt check your valve clearances. If the valve clearance is too large your compression release will not work properly and could be causing the kickback.


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## koolminx (Mar 23, 2006)

I have the same problem with my 3.5 "whoever" model probably briggs or techumseh, but the crankshaft turns straight, it run's great after starting... It kicks back when pulling it to start... after start up I get about 5 or 8 revolutions with a "LOUD Knock!" then everything smoothes out by the 10 or 15th revolution and it run;s like a top and will take 4,000+ rpm without any problems. The Flywheel key is PERFECT. Is it possible for me to oval out my coil mount holes and retard the timing a degree or two and cure this issue? I have NOT seen an answer to a post about kickback that actually solved any of the issues that weren't directly related to a broken key.
Thanks fella's! koolminx


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