etbrown4
ArboristSite Operative
She'll start on ether only. Runs really smooth.
What to try?
What to try?
Ms170 Runs Great, Very Hard to Start
- Thread starter etbrown4
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Using the choke? I had a mower that acted the same way. Throttle cable needed adjusting to fully activate the choke.
Test it by putting your hand over the throttle body air intake.
Test it by putting your hand over the throttle body air intake.
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Get fresh fuel before doing anything else.
I have seen many people try to start there saws while holding the throttle wide open. Set the choke, leave the throttle alone and then attempt to start. How do I know this?
A man walks out of Lows holding his new string trimmer with a pissed off look on his face. I asked him (parked next to me) what was wrong with his trimmer. He said in a very biological terms that it would not start. I asked him to try and start it. Well he had the throttle wide open with the choke on. I asked him if I could try. His wife shrugged and he handed me the trimmer. Now with the choke still on three pulls later it started. Your a frigging genius. Simply told him not to use the throttle until after it was running. He offered me a small cash prize but I refused. Moral of the story, try starting without holding the throttle, unless it could be flooded.
A man walks out of Lows holding his new string trimmer with a pissed off look on his face. I asked him (parked next to me) what was wrong with his trimmer. He said in a very biological terms that it would not start. I asked him to try and start it. Well he had the throttle wide open with the choke on. I asked him if I could try. His wife shrugged and he handed me the trimmer. Now with the choke still on three pulls later it started. Your a frigging genius. Simply told him not to use the throttle until after it was running. He offered me a small cash prize but I refused. Moral of the story, try starting without holding the throttle, unless it could be flooded.
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Amazing isn't it. There are only so many variations of a couple of variables, AND you would think they would all be tried before getting all tied up about it.
The low jet might be set too lean for easy starting.
It might require a special tool to make the adjustment or the carburetor might not have this option.
It might require a special tool to make the adjustment or the carburetor might not have this option.
You have been lucky, most 2-stroke engines do not want to start cold with the throttle closed. There's a reason why all the manufacturers provide a fast idle carb setting that holds the throttle partly open for cold starting, in fact most present generations of saws have the throttle linked to the choke so that when you close the choke, the throttle is automatically latched to fast idle until the trigger is blipped and you can't start them with the choke on and the throttle closed.
Sir, do you think that I am not aware of this? Back in the day my 041 you had to squeeze the trigger and push the pin in to hold the throttle open a bit plus using the choke. Now a days most all have some sort of throttle advancement built in.
Well at least 3 people per week come in with a saw that will not start. 90% will start in 3 pulls. No one reads the book because we all know how a chainsaw starts.
Now, start from the beginning. Does the choke close? Does it open when taken off? Does fast idle work? That will cure over half of chainsaw starting problems
Now, start from the beginning. Does the choke close? Does it open when taken off? Does fast idle work? That will cure over half of chainsaw starting problems
etbrown4
ArboristSite Operative
OP here. This is a one year old saw, used maybe 4 times. No adjustments made.
I'll check to make sure the choke is actually closing.
Guessing the 170 choke and run settings are like most Stihls, but to start mine 170, I push the choke lever all the way down, and I use zero throttle.
After 10 pulls and no start, I'll move the lever to the run position, give it a tiny shot of ether and it will start right up.
I'll check to make sure the choke is actually closing.
Guessing the 170 choke and run settings are like most Stihls, but to start mine 170, I push the choke lever all the way down, and I use zero throttle.
After 10 pulls and no start, I'll move the lever to the run position, give it a tiny shot of ether and it will start right up.
On the 170, you have to open the throttle before closing the choke. That allows the choke to close and sets in on fast idle. And please stop using ether - it can damage the engine due to no lube. Use a shot of mix from a small squirt bottle.
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Or the only problem could be old stale fuel.......
Was NOT trying to be insulting, it just sounded like you were telling people that the best way to start a saw was with a closed throttle. I miss the old saw feature of a button on the handle to latch the throttle open, it was easy to use and everyone understood it, with some of the newer saws, few people understand how to set the carb to fast idle without the choke.
Snowchaser
ArboristSite Operative
Adapt it to the walbro wt215 carb. Tons more power, runs better than it ever did before. Has high/low needles. Mine was ok starting before, but something was off. The wt215 swap done and it starts in 3 pulls no matter what the conditions.
I have had the choke linkage stick on MS170 and 180. Again check operation.
etbrown4
ArboristSite Operative
Op here. I'm aware of how to squeeze the throttle in order to go to full choke. My gas is fresh. Throttle linkage is not sticking.
On the Walbro wt215, is this a direct replacement... just bolt it on?
Like most everyone else on this forum, there comes a time when you decide you have spent enough time trouble shooting, and maybe it's time to replace the carb etc.
This one is a bit strange because it runs well once it finally starts, and for that reason I thought it might be one of the jets being dirty.
In my 35 hp ultralight airplane motors, I used to frequently rejet the carbs to maintain exhaust gas temps within range.
On the Walbro wt215, is this a direct replacement... just bolt it on?
Like most everyone else on this forum, there comes a time when you decide you have spent enough time trouble shooting, and maybe it's time to replace the carb etc.
This one is a bit strange because it runs well once it finally starts, and for that reason I thought it might be one of the jets being dirty.
In my 35 hp ultralight airplane motors, I used to frequently rejet the carbs to maintain exhaust gas temps within range.
I have seen a couple where the hole in the control lever wasn't drilled deep enough so the lever couldn't catch it properly and the choke butterfly would not close.
Thanks for clarifying that. If you are sure the choke is closing completely and there are no air leaks, then I'd go for another carb.
The only way to see if choke is 100% closed is to remove air filter base To visually inspect it. The metal choke rod may need a little more bend in it to close choke more.
a lot of 170 have the control lever pop up over the spring tab and thus not fully engage choke Also.
a lot of 170 have the control lever pop up over the spring tab and thus not fully engage choke Also.
When you say starts with ether, are you putting fuel into the spark plug hole or behind the air filter? Ether way, it sounds like you have a fuel delivery issue to either of those points.
-As above remove the air filter and check that the choke is actually closing.
- Make sure the fuel tank is clean of sawdust. You can flush it out with neat fuel.
- replace the fuel filter. Or run it without one briefly. That can help diagnose a blocked filter.
- check if the saw will run without the fuel cap. If so the vent to the fuel tank could be blocked.
Right so the above things are relatively simple. After this, you need to remove the air filter housing and carburetor.
- check the fuel line doesn't have an air leak. bend it around and blow through it with your mouth.
- dismantle each side of the carb in turn. Plenty of youtube videos on this. Be careful to replace everything in the same place. Spray carb cleaner everywhere, in all the holes and jets and wipe off any resin. There is a small gauze that can become blocked with sawdust.
Most saws will start after this treatment!
If you are only using the saw briefly 4 times a year, I'd seriously consider premixed alkylate fuel. A mix of normal petrol goes stale and has ethanol and other things in it that are not good for two strokes. In my experience it much easier to start a saw on premix.
-As above remove the air filter and check that the choke is actually closing.
- Make sure the fuel tank is clean of sawdust. You can flush it out with neat fuel.
- replace the fuel filter. Or run it without one briefly. That can help diagnose a blocked filter.
- check if the saw will run without the fuel cap. If so the vent to the fuel tank could be blocked.
Right so the above things are relatively simple. After this, you need to remove the air filter housing and carburetor.
- check the fuel line doesn't have an air leak. bend it around and blow through it with your mouth.
- dismantle each side of the carb in turn. Plenty of youtube videos on this. Be careful to replace everything in the same place. Spray carb cleaner everywhere, in all the holes and jets and wipe off any resin. There is a small gauze that can become blocked with sawdust.
Most saws will start after this treatment!
If you are only using the saw briefly 4 times a year, I'd seriously consider premixed alkylate fuel. A mix of normal petrol goes stale and has ethanol and other things in it that are not good for two strokes. In my experience it much easier to start a saw on premix.
