Re: [Amc-list] Old Gas, Kinda OT

["Jamie Smith" <oconner51@xxxxxxxxxxx>]

Mark,
Small engines are actually quite simple. (I work on them on a daily basis). That is a very good way to repair the plug wires, however replacing the coil is actually quite simple. Judging by your comments (take the top off the carb) I am guessing you must have a tractor with a Briggs opposing twin engine, like a 42A707 or similar model number (since this was the most common lawn tractor engine and one of the few that the top comes off the carb). Basic steps to replacing the coil on that one (if this is in fact what yours is) is remove the 8 bolts securing the top shroud (2 on each side, 2 on front, 2 on back), remove shroud, remove 2 bolts holding coil and thread the wires out of the shrouding. Thread wires from the new coil into the shrouding (short wire goes to right side of engine, or in car speak, the passenger side) and re install coil on engine (use a business card between the coil and the flywheel to set the airgap). Reinstall shroud and screws.

Those opposing head twins are actually good engines.....They can actually run on one cylinder after a rod breaks.....although they do lack power when that occurs.

Joe,
Most likely culprit is a stuck valve. We run into this quite frequently. It is quite simple to fix. If it is an L head it will require removal of the head, which is not difficult and will most likely cost you a head gasket (should be about $7). Just remove the head and then start spraying carb cleaner down along the valve stem and move the valve by hand (twisting motions to break up the gunk) then spray some lube (wd40 or something similar) down in there and start spinning the motor over to work the valve. Once it is worked loose reinstall the head and you should be set to go. Here it would cost about $60 to have it fixed. 

If it is an overhead valve you should only have to remove the valve cover gasket and use method similar to above.

Of course this is all assuming it is only a stuck open valve and not a valve that has been bent after being stuck or, worse case scenario, a broken camshaft.

Jamie Smith
Spokane, WA

>From: Wrambler242@xxxxxxxxxxx<mailto:Wrambler242@xxxxxxxxxxx>
>I personally find it very frustrationg that for all my automotive knowledge, lawnmowers and >small engines are like a dark secret that I have not been able to penetrate very far!
>Anything more then plugs or a simple top off the carb to clean the dirt out leaves me >scratching my head!
>I did replace the lower case gasket a few years back. I did some serious web searching before >diving into that one.
>the plug wires on my lawn tractor are mouse chewed in spots, rather then risk screwing things >up by trying to replace the wires coil assembly I put 1/2" heat shrink over the entire length of >the wire and over the edge of the plug boot.  It did work though!!!

--
Mark Price


 -------------- Original message ----------------------
>From: JOE FULTON <piper_pa20@xxxxxxxxxxx<mailto:piper_pa20@xxxxxxxxxxx>>
> My diagnosis was a stuck intake
> valve, but it could also have been stuck rings.  The
> ignition fired fine.
> 
> I took it to the small engine shop down the street
> after messing with it for about an hour.  The fix
> won't be cheap.
>   
> Stupid stupid stupid.
> 
> Joe Fulton
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