Motoman (newbie) here to tell a tale of woe and redemption in the Cascades of WA. It all started with a new Craftsman 48" /Intek mowing the 1 1/2acres of grass of my new digs. All was fine the first year. Summer of year 2 one cylinder went away. Compression good. Baffled. Finally pulled right valve cover to discover exhaust rocker not actuating. ***? Took engine apart and found an amazing sight.
The exhaust lobe on the camshaft had been ground "round" like a journal-no eccentric to lift the valve train. Plulled the head and found the exhaust guide was "pushed" upward to where the rocker coulld not work. The slow interference had gradually ground the lobe off. No noise . No drop in power until the cylinder went away. "This can't happen to a new Sears appliance, can it" Oh yes brother , welcome to the shadowy world of lawn tractors. "But the owners manual...? I did everything right...?
Remember the offer of a service contract at Sears, and the funny look the sales dude gave you when you said "no?" Hmm. And all the neighbors who have these things that won't start or don't work...?
I don't even remember whether warranty was up. Think so when I went straight to Briggs in WI. Very hard bunker to penetrate. Finally I got a mailing address and sent the cam there. To my surprise I received two new heads and gasket set a week later. I suspect they had seen this before. Stubborn type that I am I repositioned the problem guide and ran the tractor a while. Pulled the cover and could see the guide was again on the move. New head fixed things, but nagging thought persisted: what next ?
For fun I took the head's external temperature and found it in the 400deg F to 500deg F range. That didn't really prove anything. The nagging thought: Assembly of aluminum with pressings is done at around 400 deg F! Is this engine a time bomb? How hot does it run inside? If the tolerances are off a little stuff will begin to come apart (OD of guide low side, bore for guide in head is high side , etc.)
I had an old mechanical oil pressure gage, and I bought an oil temp gage . With these in place I deet ermined that the
The exhaust lobe on the camshaft had been ground "round" like a journal-no eccentric to lift the valve train. Plulled the head and found the exhaust guide was "pushed" upward to where the rocker coulld not work. The slow interference had gradually ground the lobe off. No noise . No drop in power until the cylinder went away. "This can't happen to a new Sears appliance, can it" Oh yes brother , welcome to the shadowy world of lawn tractors. "But the owners manual...? I did everything right...?
Remember the offer of a service contract at Sears, and the funny look the sales dude gave you when you said "no?" Hmm. And all the neighbors who have these things that won't start or don't work...?
I don't even remember whether warranty was up. Think so when I went straight to Briggs in WI. Very hard bunker to penetrate. Finally I got a mailing address and sent the cam there. To my surprise I received two new heads and gasket set a week later. I suspect they had seen this before. Stubborn type that I am I repositioned the problem guide and ran the tractor a while. Pulled the cover and could see the guide was again on the move. New head fixed things, but nagging thought persisted: what next ?
For fun I took the head's external temperature and found it in the 400deg F to 500deg F range. That didn't really prove anything. The nagging thought: Assembly of aluminum with pressings is done at around 400 deg F! Is this engine a time bomb? How hot does it run inside? If the tolerances are off a little stuff will begin to come apart (OD of guide low side, bore for guide in head is high side , etc.)
I had an old mechanical oil pressure gage, and I bought an oil temp gage . With these in place I deet ermined that the