# B&S engine on Sears Tiller



## william duffer (Feb 10, 2010)

Maybe someone will know. Its a sears tiller with a 5 hp B&S engine quite old, not sure of the age probably early to mid 90s. Its works but when it gets about five minutes in to tilling it loses compression. When I try to pull sart it again it just spins with no compression. If I turn the engine with the flywheel and get compression again but when I start it again it losses compression on the pull side. Not a engine guy and sorry for the terminology, hope someone out there is.


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## rustyjames (Jul 20, 2008)

I know on some older Kohler engines the exhaust valve can warp when they heat up and lose compression that way.


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## Thurman (Feb 9, 2009)

The exhaust valve on these engines have been known to get a carbon build-up just under the head of the valve preventing them from closing tightly. Remove the muffler, ground the spark plug wire, remove the spark plug. Preferably in a darkened area, or at night, shine a light into the exhaust/muffler opening as you rotate the engine by hand. IF the exhaust valve is closing tightly you will not see light around the valve head while looking through the spark plug hole--only for the few seconds the valve is fully closed. IF you see light the entire duration of one revolution--you will need to remove the exhaust valve for inspection and cleaning. I highly recommend you find and buy a book on these B&S engines before tearing it down. They are not hard to work on, the book is helpful. Good Luck, David


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## william duffer (Feb 10, 2010)

I will definitely do that. I took the spark plug off and cleaned it, i was full of sludge residue. It has just got dark here so I will tear the exhaust off and take a look.

Thanks Much


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## william duffer (Feb 10, 2010)

I did all of that and it appears to not be closing all the way, there is a lot of build up. So it looks like I will be tearing it down. The only problem is I have no idea of the year it was made. Will this matter when I go to buy a book or is there a way too find that out. 

Thanks Much


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## Bondo (Dec 8, 2007)

> The only problem is I have no idea of the year it was made.


Ayuh,... It can be Id'ed by the Serial #...


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## Thurman (Feb 9, 2009)

The horsepower and model number will help with the proper book. Bondo is correct in that the build date is in the serial number, there will be info in the book to decipher this. Please read directions on valve removal/installation carefully. These can be very aggravating, but do-able. I highly suggest buying a "valve lapping" tool and "valve grinding" compound at a local auto parts store. The cheap hand tool, small amount of compound. Read the book on how to do this, it makes valves seat much better. A good time to clean the carb also. A new head gasket, new plug, and you should be set to go. David


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## Maintenance 6 (Feb 26, 2008)

Before I would do a complete tear down, I'd pull the head off and see if there is just a chunk of crud stuck between the valve and seat. If you decide it needs a tear down, know how far you want to go, before you start. Pulling the piston means honing the cylinder and re-ringing. It may not need that in depth of a tear down. The serial number should be stamped in the edge of the sheet metal shroud. It will tell you the engine size and manufacturing date. Look on line for a B&S rebuild manual. If you relap the valves without a complete tear down, be careful that you don't get lapping compound down into the rest of the engine.


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## william duffer (Feb 10, 2010)

I found the serial number. I also have a friend (i know hard to believe), he has a newer model that was for a splitter that is ca-putz as well and I am going to work on that one first and test the waters. He has already bought a new one so this one is free game for me to destroy.

Thanks Much.


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## 1955dad (Aug 27, 2010)

What you have is a Sears Craftsman model # 917 298550 tiller. I just bought one on Craigslist. I'm looking for the cowl that goes over the tilling blades plus an owner's manual. Any help would be appreciated.


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## dave1123 (Jun 30, 2010)

Guys! Why is my 1963 Techumsa still running with only an oil change about every 10 years?:laughing:


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## william duffer (Feb 10, 2010)

Not sure but you might think about turning it off to give the poor thing a rest that things is older than me. Besides how are we going to keep all those small engine repair dudes in business if we buy those reliable engines. Mine blew a rod after I worked on it so I took my shotgun to the poor old lad and called it dead.

Sorry Dad no Manual.


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## Thurman (Feb 9, 2009)

Better yet, how did he change oil with it running? Sorry, "dave1123", we just had to pick a little.
One thing I learned a long time ago was to add a few drops of transmission fluid to the gas of small engines to reduce carbon build-up. Now I use "SeaFoam" in my small engines and my motorcycle to keep carbon build-up away. Works for me. David


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