Gasket-cylinder Head 271866S

I disassembled the engine. I discovered that the rod had seized to the crank, but I had shut it down before the rod broke. I soaked the aluminum off from the crank using oven cleaner and then polished the crank in a lathe. I marked all the parts and found the engine to be in spec, so I installed the rings, slid the piston home, torqued the rod to spec and turned the engine over to check for binding. It was fine, so I torqued the rest of the crankcase and head to spec. After reinstalling the engine to the tractor I added oil and fuel and it fired it up. I let it run for a couple minutes keeping an eye on things. It seemed fine so I took it out mowing. I like to break an engine in under load with out abusing it, so I put it under a varying load at various throttle settings. After about an hour of this, it had quit smoking and was running nicely.

One additional thing I did that doesn't pertain to the original problem is bring the valves to spec. On this engine, the stems have to be ground a bit at a time. I also tapped the valves to the seats. I consider the project a success. The parts come with any unusual techniques or specs needed to do this.

Pulled head, put in new head gasket

The very first thing, even before ordering the new head gasket, was to watch a couple of You Tube videos to see what was involved since I had never replaced a head gasket before.

The most time spent on the repair was spent on removing the mower hood, exhaust, fuel input, etc. in order to be able to get to the head.

After that the actual removal of the head, replacement of the gasket, and re-attachment of the head was simple.

My riding mower has Briggs & Stratton's OHV (overhead valves) and that is a pain to get the adjustment correct--that took about 30 minutes and is not included in my estimated time to replace the head gasket. The valve adjustment is a separate repair problem and needs to be done every year or two. I have found NO benefit to the OHV design--I have another riding mower with a Briggs engine and is over 10 years old and have never had a problem with it.

Final step was re-installation of all the various mower body parts.

Removed head from motor
Removed carburetor
Removed intake valve and adjusted valve clearance.
Replaced valve, carburetor, and reinstalled head with new gasket.
Mower runs great

1. Removed covers, shrouds, housings
2. Cleaned off mouse nest, wire brushed corrosion
3. Removed head bolts (broke two) to remove head.
4. Found displaced intake valve seat. Removed valves.
5. Re-set valve seat, ground valves.
6. Cleaned out combustion chamber
7. Drilled and tapped two head bolt holes
8. Re-installed head with new spark plug.
9. Remove, clean and re-install carb
10. Re-assemble, add fresh gas and run!

Replaced

Drain the oil, remove motor from the frame, turned upside down to remove crankcase cover, pulled old cam-shaft out, found broken compression spring unattached, put in new parts, gaskets, seals, then adjusted compression valves to 0.004 change oil filter and put fresh oil in. The part fit perfectly! Thank you for helping me with my problems.

Thank you!

Received two lawn tractors, an old Western Auto, Wizard, with a 12.5HP Briggs and Stratton, blowing smoke and running like crap. And a Bolens MTD with a 13.5HP Brigs and Stratton, also blowing smoke and running bad. Replaced head gaskets, on both mowers, and the problems stopped. Additionally, we seem to pick up a little extra power.

Blown head gasket caused me to have to replace the plug, so I decided to do a general tune up on them both, to include plus, air filter, and oil change.

Thanks for having the parts available.

Removed the head repalace the head gasket

I thought the float valve was not working, even after a complete carb rebuild. Pulled the head to check for burnt or stuck valves, significant carbon build up, but valves still closed correctly. Had weak spark, but it was there, so I replaced the coil, it did not run at all after that, so I pulled the kill wire from the magneto, the machine started, the carburetor adjustments were effective, better than before. Found a safety module that checks seat interlock, gear interlock, and deck engagement before you are allowed to start the machine. This module 68-2940 part number on a Toro 55600 series tractor kills the engine by grounding the ignition magneto coil.
So, I replaced the head gasket after cleaning the head and valves, put a float valve in the carb, by the way the little green ring goes in with a raised lip on the bowl side of the valve, replaced the coil and will install a new ignition switch and module coil when it comes in.