iDRY Vacuum Kilns

Sponsors:

Stihl MS 180 throttle linkage issue

Started by kengrunke, July 12, 2007, 08:44:12 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

kengrunke

Hi everyone,
I tried searching the forum first in regards to my problem, but no luck. I have a Stihl mini sawboss, MS180, that all of a sudden the other day I could NOT turn off. The linkage was stuck in the run position, so I had to take the cover off and short the contacts manually with a needlenose.
The throttle shaft popped out of it's cradle when I forced the lever up towards the off position a little too hard. Must be a built-in safety measure to prevent breakage :)
So, it took me a little while to get it back the way I thought it should be, but I wonder if a part is missing as the lever still will not go up to the off position.  Hopefully this image will help show it better:
Admin Note: Use of images outside of your Forestry Forum Gallery are not allowed.chainsawlinkage.jpg[/img]
Can anyone see how the ground contact on the left, whose right end is up against the plastic linkage body, is preventing that from rotating any further? I've had the saw for 3 years now and never had this problem before.
I'll be calling tech support in the morning, but I thought I'd post here in case someone was familiar with the problem and had a solution.
Thanks in advance for any helpful suggestions.

joe_indi

Hi,
It seems the part of the Switchshaft in contact with the short circuit spring has worn .
This has caused a well to be formed from which the end of the contact spring cannot move when the switch is moved to the 'Off' position.
Though it is possible to correct this by re-shaping the worn out bit of the switchshaft, or by decreasing the tension of the contact spring by bending it upwards, I would suggest that you replace the switchshaft.
That would be faster and eliminate problems in the near future.

Joe

kengrunke

Hi Joe, thanks for the reply but there is no wear whatsoever in that little pocket where the contact spring is resting. That's what makes this such a mystery, and makes me wonder if I dropped a little part in the grass when I first took off the cover in an attempt to shut the saw down.
I think this image, with the lever in full choke position and the pocket or "well" exposed to show the factory surface shows it fairly good:
Admin Note: Use of images outside of your Forestry Forum Gallery are not allowed.chainsawlinkage02.jpg[/img]
Do you or does anyone have this saw and could please take a look at the linkage to compare with my image? I won't be able to take this in until after the weekend, unfortunately but it would be fantastic if I can figure it out so I can do some limbing tomorrow! Or I better start greasing my elbows for the bowsaw  :D

joe_indi

kengrunke,
I do sell and repair MS180s.
I think, more than the wear on the switch shaft, it looks like your contact spring has been bent a bit out of shape.
This happens often on a 180 if you are unfortunate to have the switch shaft jump out of its lock.
When this happens, one tends to re-fix the shaft without taking care to lift the contact spring away from the switch shaft.
If this is done, and the switch is moved towards the 'Stop' position the spring bends downwards.
This in turn makes it difficult to move the switch to 'Stop' due to the xtra spring tension.
The way to check out if this is the problem is to use a finger or screw driver to lift the contact spring a bit upwards.
While holding it in this position see if the switch can move freely.
If the answer is a yes, bend the spring upwards a little bit to decrease spring tension.
If the tension is decrease too much, the switch will move around too much and even fall into the 'Stop' position by itself, so be careful.
If you accidentally over-do the bending, just remove the switch shaft from its lock to give you some room and push the contact spring downwards to re-tension it.

Good Luck

Joe

kengrunke

Joe, I'm now able to move the lever to off thanks to your suggestion. It's still a mystery how this happened to begin with, but I'm sure glad to have an operational saw again except for another problem--unrelated, but I guess I'll continue with this thread instead of starting a new one.

Now,I seem to have to a fuel blockage. If I stick my finger in the tank and jiggle the pickup filter at the end of the hose around, it will run good for a minute or two then lose power and run erratically and die or it might idle with no problem but die as soon as given full throttle. I have flushed the tank with clean gas 3 times, sloshing it around good to try dislodging foreign matter from the filter.

My guess would be to replace the pickup filter, correct? Is there a trick to removing the cap keeper to get it out of the way, and what would be the best strategy for filter replacement? The saw is a year past warranty, so I'd rather do what I can myself to save a couple bucks.

Thanks again,

Ken

joe_indi

Ken,
It does seem to be a partially blocked pickup body problem.
When you shake the saw, you increase the pressure of the air in the fuel tank, which cause the fuel to be forced through the blocked filter,
It is only a two minute job to  replace the pickup body.
First you need to remove the fuel cap.To do this use a nose plier or tweezer to get hold of the 'keeper' of the fuel cap.
It is shaped like a broad based triangle. Turn the triangle a bit so that a narrow side of the triangle can pass through the mouth of the fuel tank.Now pull the keeper out.
Its as simple as that!!
Use a bit of wire with one end bent into a hook to grab hold of the connected end of the pickup body and lift it out of the tank.
Have the replacement within easy reach before you remove the old pickup body, otherwise you will need  to go on a second 'fishing trip'
Joe

kengrunke

Joe, that was easy enough, thanks. Yes it would be easy to replace the filter, but it's an hour round trip drive to the service center so that won't happen today. The filter (pickup body) looks perfectly clean to me, I can't see the tiniest spot of dirt on it. Could it be something else down the line? I'd hate to drive an hour for no reason.
The gas I was using is not very fresh, so after I finish my morning coffee I'll mix up a fresh batch and see what difference that makes.

joe_indi

Ken,
Appearances can be misleading.
It is not only solids such as saw dust or dirt that blocks the filter.
If you leave fuel in the tank for too long a time, the inner filter insert gets gummed up, though it might look OK from the outside.
Try blowing through it.You should be able to blow freely, if not it needs a replacement.
But, as a temporary(strictly temporary) measure, you could spray a carb cleaner at the hose end of the filter and then some air.
The filter should work for some time, at least till you can make the trip to get a new replacement.

Or:
Do you have a brushcutter or trimmer handy? Pull out the filter from that to use on the saw till you buy a new one.

Luck

Joe

pemi25racer

I am having a problem with my Stihl MS180S, the lever for stop start choke position popped out of the cradle and it will not go to the stop position after I snapped it back in place and can't figure out what is wrong with it, any suggestions. I wish I could see the images that Kengrunke posted above with the same issue, it also will now no operate the choke also.

joe_indi

Quote from: pemi25racer on April 04, 2015, 04:46:32 PM
I am having a problem with my Stihl MS180S, the lever for stop start choke position popped out of the cradle and it will not go to the stop position after I snapped it back in place and can't figure out what is wrong with it, any suggestions. I wish I could see the images that Kengrunke posted above with the same issue, it also will now no operate the choke also.
Look at this image:
You need to lift the circled portion of the contact spring away from the lever before popping the lever into position. If you dont do this, the contact spring tends to lock the lever and any attempt to force the lever damages the spring

Thank You Sponsors!