# Chain saw wont start



## truenorth777 (Mar 28, 2006)

Hello

I have a mcculloh model 110 chain saw and I cant get the thing to start, I know for sure that it is a fuel issue because when I put gas into the carb it will run for a few seconds and shut down again.

So far I have rebuilt the carburetor, replaced the diaphrams, blown out all ports, replaced the fuel filter, checked the line for blocks , adjusted the needles,and it still wont run.

the gas is getting into the carburetor, but not into the intake.

I did loosened the screw that holds in the needle valve and put it together that way when I did this it does keep popping but it still wont run but when I tighten it right down it doesnt get any fuel.

So what im wondering is if this screw has to be set at so many turns out or should I be looking else where?

Hope someone can help.

Thanks.


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## hankster (Jan 1, 1998)

A good point to start is both needles out 1 1/2 turns out from fully closed.


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## 30yearTech (Sep 14, 2006)

You have to be very careful when you reassemble this model chainsaw. It's very easy to pinch the fuel line on the channel in the case when you slide the engine back in. Make sure the fuel hose crosses over the spark plug lead wire and is not in front of it or it will not line up with area in the case where it supposed to be.

The screw on the inlet needle in the carburetor should be tight on the fulcrum pin and the metering lever should be set flush with the body of the carburetor. The adjustments hankster posted are a good starting point.


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## truenorth777 (Mar 28, 2006)

Ok so I checked the fuel line and it wasnt crimped, set the carb to 1 1/2 turns open turned it over a couple hundred times and it still wont start.

I have rebuilt the carb 7 times so far and each time I have blown out every port including the small ones bye the throttle choke. but when I have to rebuild the carb again on this particular model, You have to take off all shrouds, the recoil covers about 10 or so bolts, air filter etc. and it takes about 10 min or so just to get to the carb.

So before I go and take it apart again I better get some ideas because im out.

The only problem I'm having is it isnt getting gas into the intake, if I pour gas into there it will run for a couple seconds but after that it dies again.

But the spark plug seems to smell like gas and seems to be flooded without putting gas into the carb But it will only pop when I put gas into the carb so im confused???


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## 30yearTech (Sep 14, 2006)

Which carburetor do you have, the Walbro or Zama?


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## pyro_maniac69 (Aug 12, 2007)

did you replace the gasket between the carb and the intake?

are you sure you don't have a vacuum issue where the crankcase isn't holding pressure like it is supposed to?

What do you have for compression?, if its low enough, it may not run off the carb, because putting straight gas in it is going to raise the compression somewhat enough to make it run on the gas you poured in until it burns it off

are you sure your putting the carb back together right? If you don't put the diaphrams and gaskets in right, it isn't going to work properly

are you sure the needle is set properly so that the diaphram is pushing it right? Maybe its pushing it to much and flooding it out

check those when you take it apart again


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## truenorth777 (Mar 28, 2006)

did you replace the gasket between the carb and the intake? Yep I did Replace this gasket but no improvement

What do you have for compression?, 120psi plenty enough for a chainsaw

are you sure your putting the carb back together right? Yep I have the manual and I followed it exactly

Ok so I have done the things above but I have these two questions below.

#1 are you sure the needle is set properly so that the diaphram is pushing it right? 

I'm not sure abou this one the do you just tighten the screw right down or does it have to be backed out a certain amount of turns?

#2 are you sure you don't have a vacuum issue where the crankcase isn't holding pressure like it is supposed to?

Not sure about this one is there a compression release somewhere on this particular saw ? and How do you check it for vacuum?


Thank you so much for your posts and I feel like I will eventually beable to get this thing going.


I'm not sure which carb I have, going to take it apart and I'll get back to you later.


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## powermax (Oct 29, 2007)

Well I've got the same problem on a Homelite. I've done all the same and replaced a pulse line that had a split in it.
Mine, after many pulls will start and will run like full throttle then die. While running, no manual throttle response just wide open.


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## 30yearTech (Sep 14, 2006)

What model Homelite chain saw do you have??


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## powermax (Oct 29, 2007)

It's a 410


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## luckyvision (May 24, 2007)

how about a plugged or partially plugged exhaust?


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## powermax (Oct 29, 2007)

Muffler OK and spark arrester clean also.


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## 30yearTech (Sep 14, 2006)

powermax said:


> It's a 410


Check the intake manifold, there is a good possibility that there is an air leak here. Look for a crack or a tear in the rubber manifold.


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## powermax (Oct 29, 2007)

Only thing haven't looked at closely. First thing in the am

Thanks


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## powermax (Oct 29, 2007)

Truenorth777 still with us?
Get yours running yet?


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## matt07181986 (Oct 30, 2007)

To the person that rebuilt their carburetor many times. Did you replace the welch plug when you did the carb? I have found that it is critical to replace these if you have a zama carb!


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## truenorth777 (Mar 28, 2006)

Nope didnt get it running yet but I think that I found the problem.

on the bottom of the engine (side the chain saw sits on) it has two holes in it 1 has a plug in it but the other doesnt, I took out the spark plug and cranked the engine over but there was no crank case compression.

but I found out when I covered that hole with my finger than you can hear the popping noise its supposed to have.

Is this normal to have this hole without a plug or compression release, or should I be looking else where.


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## 30yearTech (Sep 14, 2006)

No, there should be a plug in that hole. It's a machining port thats supposed to have a plug in it, you have a massive air leak into the crankcase and you will never get it started this way. I am not sure where to go for the part you need as this model saw was discontinued a long time ago. I will see if I can find any parts info and I will post what I find.


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## truenorth777 (Mar 28, 2006)

Thanks sounds great keep me posted because I really want to get this machine running its my uncles and hes had it for years and he wanted to see if I knew enough to get this thing running.

QUESTION:

So is this just a plug or does it need a compression release for the crankcase?
and would it possible to make this part myself?

anyways I will check with my local parts store and see if they have it and do some research too.

Thanks again.


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## 30yearTech (Sep 14, 2006)

truenorth777 said:


> QUESTION:
> 
> So is this just a plug or does it need a compression release for the crankcase?
> and would it possible to make this part myself?
> ...


No, it's not a compression release it's just a plug. They kind of look like a small freeze plug from a car engine.


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## powermax (Oct 29, 2007)

Well 30yeartech nailed it ! Thanks.
I saw the part but thought it was loose and sealed with the carb bolted on.
When I took it out it was in 2 pieces.
I looked up the part number and it is no longer made : - (
Further search turned them up at M&D for $4.35
I bought 3 of them... Just in case.

Thanks again. :woohoo:


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## truenorth777 (Mar 28, 2006)

Ok so I the local shop had the plug in stock and I put it in today have to wait till tomorrow for the sealant to dry and it should be good to go.

I'll keep you posted with the results.


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## 30yearTech (Sep 14, 2006)

truenorth777 said:


> Ok so I the local shop had the plug in stock and I put it in today have to wait till tomorrow for the sealant to dry and it should be good to go.
> 
> I'll keep you posted with the results.


Good Luck, hope everything works out.


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## truenorth777 (Mar 28, 2006)

Got it back together this morning, Tried it for a while and it wouldnt start I poured gas into the carb and I got it to pop so I thaught id try a little more to prime it put the gas in turned it over once and it started right up.

now its running excellent and cuts trees like a charm.

Thanks everyone for your help.


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## truenorth777 (Mar 28, 2006)

ok jumped the gun too soon the chain saw was running great but oil and gas started coming out the muffler I can get it to start but it goes through a tank of gas in a matter of a few minutes.

and it seems to be flooding out now when im running it. 

I get it going runs excellent for a few seconds, its smoking like crazy and stalls than I have to take out the plug crank it over a few times to get out excess gas and it will start again, and I go through the same steps again.

any ideas how to fix this problem now? lol.

thanks


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## 30yearTech (Sep 14, 2006)

Need to recheck the inlet metering needle and the lever setting. It should be flush with the carburetor body. Make sure you install the gasket first and then the metering diaphragm. From your description it sounds like the inlet needle is not shutting off the fuel. Make sure the fulcrum pin retaining screw is good and tight.


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## truenorth777 (Mar 28, 2006)

Yep thats exactly what it was, the needle in the carb was stuck open and was flooding out the engine. Its running good now.

Thanks again for the help.


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