#1 Shouldn't be a problem. At least the common hydro belt (954-0461)stays under tension and has to wear/ chunk badly before they go away. #2 One would think that temporarily grounding the plug would either give a cylinder w/ lower compression or a leaner feed a chance to build a bit more fuel to fire or that somehow the absolute ground rather than an arc may allow an ailing coil to fail. Admittedly a reach on both!

The man at the shop said the belt came off and broke the fan,bothers me that a new belt on a new mower would come off. Wish they wouldn't have gotten here so fast,so I could have looked at it better.
The absolute ground sounds about right,as it has no fire at all when hot and trying to start it,but as long as its running,it runs ok no matter how hot it gets. I thought maybe by grounding it,that helps somehow to excite the coil. The weird thing is,it has been doing this for the last 2 or 3 years and has gotten no better or no worse.
Thanks for come back.

Things have changed on the old mower,now I have to ground one plug for it to start cold or hot. Wish I knew what the problem was,as eventually it will probably not start at all. Will check to make sure switch is grounded.

Things have changed on the old mower,now I have to ground one plug for it to start cold or hot. Wish I knew what the problem was,as eventually it will probably not start at all. Will check to make sure switch is grounded.

Have you ever tried putting a shot of carb cleaner (NOT ETHER) into the carb before you try cranking?
I can't get my mind around why grounding one plug would increase the start-ability of the engine of the engine unless it somehow caused the cylinder to richen (more fuel present) while the plug was grounded.
If I remember, this engine was an opposed twin (correct me if I'm wrong).
The coil on those engines fires both plug wires simultaneously......so grounding one plug wire would/should effectively ground both plug wires and stop all sparking until the plug was ungrounded, at which point spark would resume.
If this is the case, you may have a carb that is too lean, or the choke is not closing completely enough.....for good starting capability.
The shot of carb spray could help determine if your carb is too lean for reliable starts.
It takes more fuel in the ratio to start an engine than to run at idle (especially if the engine is stone cold).
I don't know what you mean about checking the switch ground.
Care to expand on that notion?

I'd say that there is a breakdown in the electrics due to heat and vibration.
The carb spray is a good diagnostic method.

I had an odd one w/ an op twin the other day. It would absolutely not start cold. The float was set a smidgen below level. Once it was set a tad above level it would start on its own. 120 # on each side....

Got my Cub back and the mechanic said,it looked like a piece of a stick got thrown up in the belt and threw it off and then the belt was rubbing on the plastic fan and broke it off. Do have a lot of small sticks as have a lot of trees.
On the Husky,it is not the carburetor,as I used to try the ether before I discovered it had no fire. Not sure its an opposed twin,as the plugs dont look that far apart. Remember when I try to start it,there is no fire to either plug. Then I ground either plug,usually the right one and it starts and runs on the one cylinder,then I remove the ground on the grounded plug and it runs on both. Hard to believe the new coil is also bad,as it acts the same as the old one. I found this by accident,as I was checking for fire on one of the plugs by holding the wire about 1/8 inch from ground and found no spark,but accidentally grounded the plug and the silly thing started. The engine runs good and has plenty of power,and has the automatic transmission(variable pulley) Think I like the automatic better than the-moaning and groaning hydrostatic,which I could always fix with a new belt,but all the newer bigger ones have the hydro.
Thanks for the come back,so will start using my new Cub again and still start the old Husky once a week(and try not to get shocked while removing the ground wire from the plug) and if anything changes,will let you know.

The coil is not producing high enough voltage to jump both gaps. In these coils the secondary windings of the coil/transformer that produce the high voltage is not grounded - each end of the coil feeds one of the plugs so the output voltage has to be high enough to jump both gaps. When you ground one plug, you are forcing all the output current through the other plug. The two outputs of the coil are not connected together; if they were then only one plug, the one with the smaller gap (no matter how small) would fire. By connecting each end of the coil to each spark plug, both plugs have to fire to complete the circuit.

In your situation, if the coil in ok, then either the magnet is weak or the gap between the magnet and coil is too large.

Or is cranking too slow...

Cranking is fast,as hot battery,
I must have set the gap the same as the old coil.since It acts the same and maybe both were too large,so next time the shroud is off(probably when it quits starting at all)will move the gap closer.
Thanks everybody for come backs,as there is a lot of good information on this board.