026 Hard Starting Cold

[WoodTick007]

I have an 026 that has a clean fuel filter and new kit in the carb. When cold I can pull for ever and it will not start. If I put a little mix in the carb, it starts first pull and will start with just a short tug on the starter rope after the initial starting.. I have checked the choke and its properly closing. Any suggestions would be great.

Thanks.

 

[DirtTroll]

Sounds like a air leak on the impulse line.

 

[stihltech]

fast idle

I s the throttle plate opened up on fast idle and choke ?

 

[buckduck]

Air Leak

I had an 026 that acted this way. Really hard to start. If you ever got it running, it was a demon from hell. Like really high RPM's. Too much oxygen; running lean...... it's getting air from somewhere.

Bad Seal.

 

[WoodTick007]

Air Leak?

WHat is the easiest way to locate and airleak on a saw? Can it be sprayed with something to indicate the area of the leak? Example: If I were to spray WD40 on the crankseals and around the impulse line???? Please let me know

Thanks!!

 

[stihltech]

Woodtick, check out the fast idle first. The fast idle cam breaks of the master control lever. I know of many Stihls that will not start without it. Go for the easy stuff first, the seals are fairly durable.

 

[WoodTick007]

Thanks StihlTech.

I checked the fast Idle and the carb is opening. Once the saw starts the idle is irratic. It idles without stalling and the top rpms are 12,400-12,700. The saw cuts fine it just needs to be primed with fule on the initial start of the day.

Greg

 

[monel_funkawitz]

This definately sounds like an impuse line problem.

To make it easy to understand, the impuse line is ported from the crankcase of the engine. The pressure/vacuum cycle that the impulse line sees operates a sort of a fuel pump in the carb. What is happening is you are not getting enough pressure/vacuum on this line when hand starting it to operate the fuel pump. When the engine is warm, there is enough fuel in the carb and crankcase to make the engine run until it can pump gas in the carb.

You need to check the impulse line from start to finish. All fittings and line. Then check the carb from top to bottom, tear it ALL apart. Sometimes the valves or diaphram stick in the carb and causes this to happen. Other causes are crankcase air leaks and low compression, but the other things are usually the culprit.

 

[Joey P]

I find sometimes when a customer cmomlains about something like this that the choke int he air filter isn't closing all the way. Check that out first. Like Stihltech says start with the easy stuff.

 

[Jacob J.]

If the saw had an air leak in the impulse line, it would be racing, not dying.

Greg, did you replace the inletting needle and lever when you rebuilt the carb? Did you remove the adjustment screws all the way out and clean the seats with non-chlorinated brake cleaner?

 

[DirtTroll]

Originally posted by Jacob J.
If the saw had an air leak in the impulse line, it would be racing, not dying.

I hate to say you don't have a clue what youre talking about. But, you don't have a clue what youre talking about. The impulse line pulses the diaphram which in turn pumps the fuel to the carburator. If you have a leak in the impulse line, it wont pump the diaphram and you wont get any fuel. This becomes a non running condition. Quite the opposite of racing.

Another possibility could be that the diaphram needs replacing.

 

[Joey P]

Accually you are wrong. Even though the carb is not getting complete impulse because of a leaking impulse line, the saw will still run. There are 2 things that happen with a cracked fuel line. 1, extra air is allowed into the motor making a lean condition. 2, some of the impulse is lost through the crack. The carb still gets some impulse but the combo of extra air and not enough fuel running through the carb makes the saw race like it is extremely lean.

AH but you may say what if the impulse line is completely broke or off of the carb or crank case. The saw will still run. The air passing through the venturi of the carb creates enough suction to pull some fuel into the motor, it won't give the same lean racing condition as a cracked one, It will barely run.

I have seen numerous saws with cracked impulse lines and broke/unattached impulse lines and every single time the saw will run somewhat.

 

[DirtTroll]

Originally posted by Joey P


AH but you may say what if the impulse line is completely broke or off of the carb or crank case. The saw will still run. The air passing through the venturi of the carb creates enough suction to pull some fuel into the motor, it won't give the same lean racing condition as a cracked one, It will barely run.

If you think you know what you are talking about then disconnect the impulse line and see if it will start (it won't). The venturi will not pull NO WHERE NEAR ENOUGH SUCTION TO PULL FUEL FROM THE TANK WITHOUT THE DIAPHRAM. Try it and try to prove me wrong.

 

[Joey P]

I dont think you understand.....I know from experience......it will run.......not good....not good at all....but it will run. Most of my experience with this has been from my own mistake, not reconnecting the impulse line at the crank case. Start it, runs like $*#@ realize what I did, reconnect and it runs good.

 

[monel_funkawitz]

I am new, so I don't want to start a mud slinging match here.

Every two stroke is different. I am sure there are two strokes out there that will run without the impulse line hooked up. From my experience with strokers is that with a leaky impulse line connection, the saw cannot draw fuel by hand cranking. It needs enough RPM to overcome the leak. With a dry carb, it needs gas squirted in to make the engine start and make the carb pump fuel.

HOWEVER, with a REALLY REALLY bad impulse line or one that is not connected, the saw will race due to the fact that the saw is going lean from not pumping enough fuel, plus extra air getting sucked into the crankcase. Slight leaks usually make cold starting difficult without a little drink of gas to help it.

 

[DirtTroll]

Originally posted by Joey P
I dont think you understand.....I know from experience......it will run.......not good....not good at all....but it will run. Most of my experience with this has been from my own mistake, not reconnecting the impulse line at the crank case. Start it, runs like $*#@ realize what I did, reconnect and it runs good.

I simply don't believe a word you are saying. Sorry. You are saying you can start a saw without a diaphram installed in the carberator, which is the same condition you have without the impulse line hooked up because the diaphram is no longer working and will not pump fuel with the impulse line disconnected. You have lost any crediability you might have had with that statement. Also, I'm tried of arguing with someone who thinks the saw runs on magic and will not post to this thread anymore. It is a waste of my time.

 

[stihltech]

pulse

yep, they will run, really bad, but it will.

Check all the things listed before going inside. If hoses check OK, check the carb inlet needle for sticking. The lever must rotate freely around the axle, and I do mean freely!
As for seals, many times a bad seal will appear oily. Pretty tough to spray around a seal when the saw is running, too much rotating mass around the seals. I have found a few seals with the garter spring out of place, but the saw will usually start good with this condition

 

[Joey P]

Re: pulse

Originally posted by stihltech
yep, they will run, really bad, but it will.

Glad someone can back me up.

Troll maybe you should accually know what you are talking about before you open your mouth and flame someone. I have seen countless numbers of saws with somekind of impulse problem.

I dont usually flame anyone on here.....in fact I only post when I feel I can really add to the discussion. I just cant stand it when people flame people and really have not a clue what they are talking about.

 

[Tim Gardner]

After checking the impulse line and its connections, that the carb inlet needle is not sticking, cleaning all the holes in the carb and air screws, and replacing the diaphragm, what else could the problem be? The saw needs a shot of fuel in the carb to get started and will not idle after starting.

 

[stihltech]

check and check

I went back to the beginning and did not see mention of the fuel hose, check it for cracks if you did not already.
It appears we are looking at an air leak. If I had it in front of me, I would go back through and check the rubber parts again, and then air test it. Without an air test at your diposal, remove the clutch and flywheel. Take a good look at the seals, be wary of a seal that appears oily around the sealing surface. Also make sure the rubber part is connected to the steel shell. If not, the rubber lip will turn with the crank.
Check the cylinder screws also. If they seem loose, look for a really clean spot around the base of the cylinder indicating the gaskwt is leaking.
After that, head for Pike NY, I will save some time for ya.