Heymow - Lawnmower Racing Forum

Engine Help => Briggs Flathead => Topic started by: daddyracing on May 07, 2014, 09:58:50 pm

Title: mow better timing
Post by: daddyracing on May 07, 2014, 09:58:50 pm
I got a stock model 28 flathead. Is there anyway to advance the timing or anything? Maybe for a little more bottom end. Just trying to get some info if you guys can help
Title: Re: mow better timing
Post by: The Tank on May 07, 2014, 10:03:49 pm
The ignition timing you can with an offset timing key for the flywheel. I know EC sells them.
Title: Re: mow better timing
Post by: Jeff McKelroy on May 07, 2014, 11:57:55 pm
The ignition timing you can with an offset timing key for the flywheel. I know EC sells them.

Up to 9 degrees.
Title: Re: mow better timing
Post by: daddyracing on May 08, 2014, 09:54:10 pm
Ok I found them on ec. But how exactly does it work?
Title: Re: mow better timing
Post by: Jeff McKelroy on May 09, 2014, 10:55:53 am
Ok I found them on ec. But how exactly does it work?

As far as flywheel hubs go, the key is just an indexing tool.  It's the taper of the outside of the crankshaft and the inside of the flywheel hub that actually grip each other (Which is why it's so important to lap the hub to the crank).

So think of it this way--cut a flywheel key in half, long-ways. now put it back together, but one half offset to the other, meaning you aren't quite lining up the pieces.  The offset key works the same, but is more accurate.

Don't know if that makes sense, but there you have it.
Title: Re: mow better timing
Post by: daddyracing on May 09, 2014, 10:07:46 pm
As far as flywheel hubs go, the key is just an indexing tool.  It's the taper of the outside of the crankshaft and the inside of the flywheel hub that actually grip each other (Which is why it's so important to lap the hub to the crank).

So think of it this way--cut a flywheel key in half, long-ways. now put it back together, but one half offset to the other, meaning you aren't quite lining up the pieces.  The offset key works the same, but is more accurate.

Don't know if that makes sense, but there you have it.
.

yes this makes complete sense. Appreciate it guys
Title: Re: mow better timing
Post by: Cromwell C4 on May 09, 2014, 10:21:54 pm
Just use a degree wheel, and set your timing to whatever you desire
Title: Re: mow better timing
Post by: jerb on May 14, 2014, 12:07:06 am
If you lap the flywheel hub to the crankshaft taper, a key is not needed at all, if you use a degree wheel you can set timing wherever you like that way, but if its a stock engine, dont expect big gains  ;)