MS170 bar oiling

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

T

TonyC72

10 Year 15 Year
Joined
Oct 8, 2009
Threads
2
Messages
18
Hi everyone,

I have a Stihl MS170 that does not deliver enough oil to the bar. It worked fine when new, but then didn't get enough oil to the bar. I have had it repaired at a Stihl dealer, who replaced the oil pump Pt. # 1123 640 3200, but it still leaves about three quarters of the bar oil in the tank for every tank of gas. I took it back, but they said that it was what Stihl had done for the environment. I didn't really believe that one!! I have taken it apart as far as I could (even committing the cardinal sin of using a rap wrench to remove the clutch. Fortunately after replacing it the saw still works.) and found that the worm gear was in good shape, and the driver spring did engage with the drum, and that the pump turned easily. I don't know what to do now. I have searched this forum, but could not find an answer. Perhaps someone would point me in the right direction.

This is a wonderful mine of information, and my thanks to you all.

Tony.
 
You should have 20% of the oil left in the tank when you are out of fuel.

This is a standard rule of thumb for most all chain saws.

The variables that will chainge this is if you do a lot of ripping or run a longer bar or more agressive chain than normal. The MS 170 only has one or two options for the cutting attachment so you are good.

Does the saw leak any oil? If so, from where?
 
Thanks for the quick reply.

I have a 16" bar that came with the saw, but an aftermarket chain (.043") that is a bit more aggressive. There is a small oil leak around the pipe that enters near the pump area in the middle of the bottom of the saw.

Tony
 
Remove your starter assy.

With the saw in the upright or operational position, you will see a tank vent on top of the oil tank. It is a duckbill valve. Using a small pair of hemostats or needle nose pliers you can remove it and make sure it is clear.

To test this before you do anything, run the saw until and when it starts to starve the chain for lubrication, loosen the poil cap and see if it starts putting out oil again. If it does, you know the tank vent is plugged.
 
I did as you suggested and found that it never completely stopped oiling, but a very small amount. I removed the starter, and checked the duckbill, and that was clear. I then crosscut about a 10" Sycamore log, and after 1 cut, the chain where it cuts was dry, a small amount of oil was on the top section of chain. I ran the saw without the bar and chain, and oil came out, but also bubbles of oil. Is that normal?
 
Is that where the oil line goes into the bottom of the engine? If so, can you point me to any instructions on this forum, on how to dismantle the saw to get to the part?

Thanks D'Animal.

Tony
 
Remove the black expansion plug that is located below the bar nuts. Push the rubber Anit Vibration mount toward the oil cap. This will allow you to move the black handle out of the way enough to get to the screw.

I would first reach inside the tank and pull the filter off. With the filter off, apply a slight pressure to the hose. It will show you where the hole is. Too much pressure and you will split the line.
 
Thanks D'Animal,

I will do that to-morrow, and then get back to you if I still need you, and Boy, us chainsaw guys really need you.

Thanks again

Tony.
 
D'Animal said:
Remove your starter assy.

With the saw in the upright or operational position, you will see a tank vent on top of the oil tank. It is a duckbill valve. Using a small pair of hemostats or needle nose pliers you can remove it and make sure it is clear.

To test this before you do anything, run the saw until and when it starts to starve the chain for lubrication, loosen the poil cap and see if it starts putting out oil again. If it does, you know the tank vent is plugged.
Click to expand...

Wow, this seems to be the same thing I'm dealing with on one of these Huskies. Makes sense, if there is a vacuum created in the tank, no to very little oil will go to the bar. One of the units I'm dealing with works fine untill it gets worked up to an operating temp. Do you know if Husqvarna has the same setup?
 
If there is a hole in the line it is literally losing it's prime. Gravilty will refill the line with oil and it will work again until the hole is exposed or there is a demand for oil (you rev the engine up).

I will check on your Husqvarna. They have different style tank vents through the models.
 
Thanks, and I concure with Tony...Your .02 here is greatly appreciated ..:)

Model I'm dealing with is the 455..And I'm rebuilding a 51 which someone ran straight gas in it.

An outdoor power section? Got my vote..:cool:
 
Last edited:
D'Animal said:
Remove the black expansion plug that is located below the bar nuts. Push the rubber Anit Vibration mount toward the oil cap. This will allow you to move the black handle out of the way enough to get to the screw.

I would first reach inside the tank and pull the filter off. With the filter off, apply a slight pressure to the hose. It will show you where the hole is. Too much pressure and you will split the line.
Click to expand...

I tried to put air to the oil pipe from the tank, but was unable to as there was not enough pipe slack inside the tank, so decided to take off the tank and supply pipe. Cleaned everthing, and put 10lbs pressure in the pipe, and found no leaks, The elbow fits snugly in the hole, and so put everything back together, and filled tanks and began sawing. After about 5/8 tank of gas gone, the sprocket nose seized up, and when I checked the oil, there was over 3/4 tank left. Without the bar on, it still pumps about the same amount and is intermittant.

So do I now look at the pump itself? When I had the clutch off, the nylon driver was good, and the driver spring fitted snugly, and engaged the cluthc drum when installed. The pump itself turned easily with my fingertip. I didn't understand the part about getting to the screw, as the only screw I saw was I think holding the engine on.

Tony.
 
Last edited:
It's semi-chisel from Cutters choice with .043" tang, but the cutters appear to be regular 3/8 low profile type. The Cat # is 17S 3/8 LP .043

Tony
 
You must log in or register to reply here.

Share this page

Back
Top Bottom