Stihl 031 Quickstop just won't Start..........HELPPPPP

[ozziechainsaw]

Hi again guys,

I am needing some advice or help with my Stihl 031 quickstop. Let me set the scene. So I got the saw from a friend who hadn't used it in 10 yrs or so. When I got it I checked spark, which it has, I did a compression test which was very good for it's age, 150 psi. The main thing that was wrong was the starter recoil rope had broken which i changed as well. So after it was all checked cleaned and fixed I tried to start it. And nothing, so I tried and tried and tried. I checked the points gap, which was within spec, checked the clearence of the flywheel to the coil. It was basically touching the coil so I reset it to factory specs.
And agin nothing, will not start. So i got a rebuild kit for the carby, cleaned everything and tried agian. NOTHING. I pull the carby apart 5 times just to make sure I didn't miss anything and still it WILL not start.

I thought , stuff it, maybe I did something wrong with the carby rebuild and I just cannnot see what i did wrong so i purchased a brand new chinese carby and set the high and low fuel mixtures before I fitted it and once again IT WILL NOT BLOODY START.

If I spray some ether into the cylinder and it tries to start and fires for about 1-2 seconds and then stops. I have tried everyting. I am at my wits end. I am needing HELP.................anyone ?

 

[hotshot]

Make test block/offs & pressure test it, or take it to your local saw shop that can.

Sounds like it may have crankcase leaks, as now it can’t feed itself, after 40 plus years, lol.

 

[Marian]

Hi first check spark plug. Take it out from cylinder, put in ignotion cable and attach it with threat to cylinder head (make good contact). Now wen you turn with starter , must you see on spark plug spark fire. When you dont see that, check spark plug gap, cca 0,5mm ,und clean spark plug contact with steel hand brush. Ignotion system /coil have not problem with function after lot of years. It must 100% function after cleaning. Spark plug together.

 

[hotshot]

Hi first check spark plug. Take it out from cylinder, put in ignotion cable and attach it with threat to cylinder head (make good contact). Now wen you turn with starter , must you see on spark plug spark fire. When you dont see that, check spark plug gap, cca 0,5mm ,und clean spark plug contact with steel hand brush. Ignotion system /coil have not problem with function after lot of years. It must 100% function after cleaning. Spark plug together.

It runs if you put gas in the cylinder...

 

[Marian]

Wenn ignotion system is function good, then must you check fuel system between carburator and fuen tank, check if isnt fuel line "crack" , many times that was misterious problem . Crack on fuel line is many time inside fuel tank. Check it precision.

 

[ozziechainsaw]

I have replaced the pick up fuel line out of the tank, the filter and the fuel hose from the tank to the carby. I even put a brand new genuine Stihl impulse line in.

Crank pressure/vaccum is the only thing I haven't checked. If I wind the motor over with a drill and put my finger over the impulse line coming off the crank case will or should i feel vaccum ?????

And yes if I spray some fuel into the cylinder with will try and start for a second or two.

Justin

 

[Marian]

Your problem is with fuel :
# have you bad riding pressure from crank case ( impulse line,crank shaft sealing, crank case sealing)

# or have you bad fuel line from tank, (crack on fuel line, or bad filter )

#or have you bad carburator:
Membranes is old and hard.
Or any gap L (low rpm ) is dirty.

 

[Marian]

No, must you make it with starter

 

[Marian]

Have you vacuum tester?

 

[Marian]

Can you take litle bit of oil on end of impulse line, with starter turning with hand can you see how it flying up and down.

 

[Marian]

Wenn can you see oil moving end of impuls line, is not enought.
This pressure can you testing with vacuum gauge, wenn you take carburator down, connect vacuum gauge on impuls line on crankcase (carb istn on cylinder) then can you turning with starter how wenn you staring chainsaw normaly.
With rurning can you see cca -4 -5 hG on vacuum gauge.

Wenn you havent vacuum gauge must you checking crangshaft sealing with pressure 10psi, i mean that you know how. 10psi.

 

[Marian]

Vacuum gauge, 3$

 

[alexcagle]

If you don't have a pressure tester kit;
From easiest to most difficult :
Since it fires with fuel in spark plug hole, I would check your intake boot first..
Next, remove the muffler, and blow through it to check for blockage. If the spark screen was absent, there could very well be a mud dauber nest.
Also while the muffler is off, inspect the piston's condition, and check for looseness in relation to movement of the crankshaft Vs what the piston is actually doing.
Next, I would pull both the flywheel and clutch off.
See if one of the seals is ripped up from a bad bearing. Also, while you're in there, inspect the condition of the flywheel key area on both the crankshaft and flywheel. Plus see if the crankshaft will wiggle up and down.
Lastly, pull the carb and look up the intake boot at the piston skirt for possible damage.
Those will probably render a fault discovery.

 

[RC Cole]

I had similar problems with a cheap Poulan I got cheap. Fuel line were connected I correctly

 

[Snowchaser]

Did you check the carb diaphragm lever? Should be flush with the top of the carb body. Use a straight edge across and should be touching or very close. Too low and wont open the main jet needle valve, too high and gas will dump out and flood. Did you carb/choke cleaner through every passage and pull out your hi low needles to verify everything is clean? There is a screen on the back side of the main jet needle. Careful you dont blow it out. The high/low needles should be 1 to 1-1/4 turns out. Be very gentle bottoming them out. I have had points that show spark but wont run as it was too weak. China carbs can cause more problems than they solve.

 

[ozziechainsaw]

If you don't have a pressure tester kit;
From easiest to most difficult :
Since it fires with fuel in spark plug hole, I would check your intake boot first..
Next, remove the muffler, and blow through it to check for blockage. If the spark screen was absent, there could very well be a mud dauber nest.
Also while the muffler is off, inspect the piston's condition, and check for looseness in relation to movement of the crankshaft Vs what the piston is actually doing.
Next, I would pull both the flywheel and clutch off.
See if one of the seals is ripped up from a bad bearing. Also, while you're in there, inspect the condition of the flywheel key area on both the crankshaft and flywheel. Plus see if the crankshaft will wiggle up and down.
Lastly, pull the carb and look up the intake boot at the piston skirt for possible damage.
Those will probably render a fault discovery.

Hey Alex,

some of this I have done.

1. I removed the exhaust and made sure it was clean, which it was.
2. checked the intake manifold, twice and it is perfect
3. I compression tested the engine cold. It has 150 psi, there are some marks on the piston but nothing major or alarming. I would expect a saw of this age to have some minor marks

I had the fan wheel off so I could see and double check the point gap. Which was with in spec. The only thing I moved was the coil so I could get the clearance correct. When I checked it the first time the coil was touching the flywheel so I adjusted it to get the correct clearance.

I'm thinking I might pull everything apart again that has to do with the ignition system and have a better and closer look. Maybe i did something wrong.
Honestly this has me really stressed. I was so sure it was a fuel problem, that's why i purchased a new carby and after fitting it only to find it is doing the exact thing is very distressing and upsetting.

I will try and get photo's tomorrow night of the piston.

Justin

 

[HarleyT]

It sounds like you need to focus on the ignition system, just because a weak spark is present, doesn't mean that it is functioning correctly. If the compression is decent, a saw will run for a few seconds
on a shot of fuel sent down the carb throat, so the problem is likely ignition.

 

[HarleyT]

The flywheel has the 2 access plugs to adjust the points?
You need to get in there and really clean those points, I use a woman's {or man's, or whatever they identify as, etc..} fingernail emory board and polish them up real good. You need the flywheel, or the cam tool, to set the points @ .016, then I like todo the final cleaning with a strip of clean paper, to remove any oils and dirt. Just close the points on top of it, and pull out the paper.
Do this properly, and you will likely see improvement, or even a cure.
If you have better running, but still runs poorly, then you know that you are in the correct area, and then can think about replacing parts like points and cond.

 

[ozziechainsaw]

Yep, sounds like a plan. I will start there and work forwards.
thanks everyone for the advice.

 

[trappermike]

One thing I'd check is that the intake boot is not cracked or broken and that the impulse hose is not cracked or broken,this was very common on these saws,you'll have to pull the fuel tank off to check closely. Also the ignition should be able to fire a 1/4" gap,or points could be dirty and need to be cleaned.