John Deere LA125 Lawn tractor 21HP B&S single crankshaft Oil Seal needed.

[Rock Crawler]

I bought a clean used 570 hour John Deere LA125 with a bad head gasket for $150 a few weeks back. It had and held oil in it, but she smoked like nothing you have ever seen after around 3-4 minutes. So I ordered the head gasket, valve cover gasket, new oil filter, spark plug, fuel filter, I replace it all and torqued the head bolts to 18 LB/FT and waited and hour and pulled to 20 LB/FT. Filled it up with fresh Mobile 1 and gave it a test run and she ran perfectly. Oh, I reset the valve lash to 0.004" and 0.006" while going together.

So I was happy, I have less than $250 in the machine and I won. But did I? I pull it into the shop and leave it rest a week or so and my son notices that one night it essentially did an oil dump on the floor. And through the seams in the concrete to the lower level... right on top of my beloved Kubota L3560 hood! Bastard! It peed on my Kubota! Rude. Anyways, my assumption is that the fresh Mobile 1 with its cleaner/emulsifiers went to work and removed build up on the crank/seal interface and created a new leak path. The previous owner admitted to not being mechanical and not heavy into service and that he had a neighbor do an oil change and blade sharper every spring. Maybe it was changed, maybe not. Maybe changed with the cheapest oil found.

So now I need a lower crank seal on a B&S 331877 21HP single. I can not get my google foo to locate a seal. I need help if any of you are good at parts digging.

 

[Rock Crawler]

The engine model # is a 3318770113B1, SN 071228ZD96064.

I think I found the part number 795387 as the correct seal part, if so do I also need to replace the crankcase gasket that I suspect is part # 607110? I was hopeful that I could stand the frame vertical and just remove and replace the crank seal without pulling the engine.

 

[Richard001]

Looks like Jacks Small engine has it:

https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/briggs-stratton/briggs-stratton-engine/200000-399999-series/331800-to-331899/331877-2371-g5/camshaft-crankshaft-cylinder-engine-sump-gasket-set-engine-lubrication-piston-rings-connecting-rod-warning-label

Richard

 

[Richard001]

The engine model # is a 3318770113B1, SN 071228ZD96064.

I think I found the part number 795387 as the correct seal part, if so do I also need to replace the crankcase gasket that I suspect is part # 607110? I was hopeful that I could stand the frame vertical and just remove and replace the crank seal without pulling the engine.

It has been done before.

 

[tomplum]

Yes. No need to pull the sump or the engine to do the seal. Wait for that when you do the cam!

 

[Rock Crawler]

Should I be heading at the camshaft now at 570 hrs as a preventative? What fails on the camshaft on these, I saw something about plastic... they could not have a plastic camshaft?

 

[tomplum]

The compression release arm breaks off. They are all metal, but hopefully yours is good for the duration. Just a poor attempt of a gentle ribbing. Sometimes the best the best laid plans don't go as they should!

 

[Rock Crawler]

I got the thing cheap and want to get it going for a hunting/camp prpoerty that I bought this year. Of course, it had the head gasket, fixed that in within a day or 2 sitting in the shop... the new oil all dumped out. Hopefully I will get the seal and install it and this thing can give me a few years.

I did also get a free 1988 Cub Cadet 1810 shaft drive that runs and works as it should aside from the rear disk brakes, but being an 1810 Hydro, you really do not need brakes. That one may get sold, a buddy of mine who is into sled pulling older garden tractors said that the 1810 should sell for around $500-$750. I could also keep the 1810 GT and sell the LA125 yard tractor. The LA125 "looks" nice, the 1810 looks its 35 years of age. The 1810 is massively better built and more heavy duty... decisions.

 

[jgayman]

Should I be heading at the camshaft now at 570 hrs as a preventative? What fails on the camshaft on these, I saw something about plastic... they could not have a plastic camshaft?

There is nothing preventative you can do. The automatic compression release mechanism on the camshaft has a bad habit of breaking on the B&S 31000-series engines. I have an Ariens with the same engine and I've replaced the camshaft three times in 7 years. B&S knows about the problem but refuses to do anything. As you can see below, the ACR components look like something that belongs in a pocket watch, not an engine.

 

[RandyT]

There is nothing preventative you can do. The automatic compression release mechanism on the camshaft has a bad habit of breaking on the B&S 31000-series engines. I have an Ariens with the same engine and I've replaced the camshaft three times in 7 years. B&S knows about the problem but refuses to do anything. As you can see below, the ACR components look like something that belongs in a pocket watch, not an engine.

View attachment 825249

The 21xxxx.28xxxx,31xxxx,33xxxx all use the same camshaft part number so not limited to just your engine. But the main reason Briggs doesn't fix it is because it isn't as widespread as people think. Even if 100K fail every year compared to over 10M engines.