Outdoor Power Equipment and Small Engines - Yard Machine 38" cut with 12.5 hp Briggs

I have a Yard Machine riding lawnmower that I have to pull the engine and look to see why there is no compression. It is the either the piston arm or wrist pin or something. Won't be able to tell until I get the darn thing of of the mower. It has two pulleys and having a devil of a time getting them off. I am using a gear puller, but doesn't seem to be budging. Might there be a special tool I need to get these pullies off. The engine is a 12.5 hp B&S 28T707 1154-E1 000110ZD..

Thanks in advance!!

Mike

a little WD-40 or penetrating oil, applied a few times over a period of a couple of hours helps

i've also used a little heat from a torch, even just a propane torch - be careful and keep flame real low and feed the pulley heat moreso than the shaft - the pulley will expand faster than the shaft - i just pulled one, and after putting the gear puller on the pulley and tightening it, ie giving the pulley constant tension, fed it low low heat around the center - when it expanded enough, it popped loose

but again, be real careful with the heat - keep it low - heating too much you can affect the temper of the pulley's steel if not warp it

What makes you you think the problem is "piston arm or wrist pin or something" I suggest you perform a leakdown test. The problem may just be a leaking valve.


Building and Using a Cylinder Leakdown Tester (http://vmaxoutlaw.com/tech/leakdown_tester.htm)

- Harbor Freight Tools - Quality Tools at the Lowest Prices (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94190)

I will try the penetrating oil and see if that works to loosen it. I know it's not the valves because I can hand turn the engine three or four times and it stops like something is blocking it. I then turn it the other direction 3 or 4 hand turns and it stops again like something is blocking it.

With knowing you know the problem is internal to the engine I suggest you look at the parts breakdown for your tractor to determine what devices are used to secure the pulley. It may be possible you are fighting a locking feature.

Localized heat and penetrating oils are about the best removal options. I have had to take the high-speed grinder and cut them off in extreme situations.:(

With knowing you know the problem is internal to the engine I suggest you look at the parts breakdown for your tractor to determine what devices are used to secure the pulley. It may be possible you are fighting a locking feature.

Localized heat and penetrating oils are about the best removal options. I have had to take the high-speed grinder and cut them off in extreme situations.:(

Thanks everyone for your input. I sprayed this stuff called PB Max from Home Depot on the shaft and inside the key way. I let it sit for a couple of days and slid right off. The bottom part of the connecting rod exploded and little pieces were everywhere along the bottom of the crankcase, fortunately no other internal damage!!