051 filled crankcase with oil, Help!

rbmopar · Sep 28, 2005

Hello all, this is my first post. I have been reading the posts on this forum for some time now, there is a lot of good info. I was out fixing the oiler on a Homelite C-5 tonight when I decided I should fire up my 051 as it has been a few months since it ran last. I gave it a good yank (no decomp) and it turned about a quarter revolution and hydrolocked. Needles to say, my hand is sore now. My question is what seal went bad? Do I need a new oil pump, or just an O-ring? Another question I have is about the worm gear on the 051. I have a parts saw that has a different outer diameter worm gear than my good saw. It is the part that contacts the crank seal, not the worm itself. I asked my Stihl dealer about this and the computer only shows one part number. I was planning on using the saw this weekend to buck a couple of 30" windfall ash from a storm earlier this year, so any help would be appreciated.

Stihl 041 super · Sep 28, 2005

The seal that sounds like it is bad is the pto side which is the clutch side. Also if you want to get it running take out the spark plug and crank it over until you see no more oil commin out of the spark plug hole. I think you can run it without a new oil seal for a while itll only give you problems when youre trying to start it once its running the oil seal should work again and it should run like normal just with more smoke.

sedanman · Sep 28, 2005

You need to replace the seal on the oil pump where it slides into the case. The oil pump on that saw comesout from the front after you take the inside spike off. You'll find it takes more effort to get the pump back in with the tight seal than it does to slide the old one out.

Grande Dog · Sep 28, 2005

There's a possibility it might be the crankcase gasket.

Grande Dog
Master Mechanic
Discount Arborist Equipment and Tree Care Supplies

stihltech · Sep 28, 2005

pump

Replace all the seals in the pump and it will be fine. It could be the gasket, but the odds are 100 to 1.
Start it outside afterwards as you will not see the saw for the first few minutes.

rbmopar · Sep 29, 2005

Thanks for the info, I'll pull the pump out and replace the seals as soon as I get a chance. Any help on the different worm gears?

tkemble · Sep 29, 2005

I've seen three different worm gears in the 051. The real old ones have pins that connect the the clutch drum for a drive system. Then they went to the sloted style clutch drums. There are two different worms for this. Stihl changed the size of the oil seals on the clutch side during production of the 051. If your saw has the large diameter worm gear that is the old one. I have only seen one saw with this worm gear, but I thought I saw one of these worms on ebay last week. Actually Dean was selling It. The newer worms have the smaller diameter. That is the one your dealer has on his IPL. The 075 and 076 use this worm too.

rbmopar · Sep 30, 2005

Ok, so I should be able to run a small worm in an older saw if I use the new style seal, If the O/D of the seal is the same. Got the saw running tonight, and the parts are on the way.