I have a 1990 Sears model 917.2559101 18 hp garden tractor. Runs great until about 20-45 minutes, when it just dies. Then must sit for awhile before restarts. The hotter the weather, the quicker it dies.

I've changed plugs, cleaned fins, air filter. So from previous answers I'm guessing it's ignition related. Is the "coil" the same as what's listed as "Armature Assembly (Motor)" on the "Starter Motor Group" parts diagram?

It's a Briggs & Stratton model no. 422437 engine, type no. 1256-01

I have a 1990 Sears model 917.2559101 18 hp garden tractor. Runs great until about 20-45 minutes, when it just dies. Then must sit for awhile before restarts. The hotter the weather, the quicker it dies.

I've changed plugs, cleaned fins, air filter. So from previous answers I'm guessing it's ignition related. Is the "coil" the same as what's listed as "Armature Assembly (Motor)" on the "Starter Motor Group" parts diagram?

It's a Briggs & Stratton model no. 422437 engine, type no. 1256-01 Have you taken the shroud off to remove grass and other organic debris that has likely built up restricting airflow over the years?

I do not think this is an over heated engine. Sounds like your coil is failing when it gets hot. The coil is not " "Armature Assembly (Motor)" on the "Starter Motor Group" parts diagram? " It should be part #11 in this diagram. http://www.searspartsdirect.com/partsdirect/part-model/Craftsman-Parts/Riding-mower-tractor-Parts/Model-9172559101/0247/1509200/00052987/00001?blt=06&prst=0&shdMod=9172559101 look at the upper left corner of the diagram.

Hi,
Replace the armature with #394891.
Peace,
Clarke
http://bsintek.basco.com/BriggsDocumentDisplay/Z6ooACVJ1DajI.pdf