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Husqvarna 55 Chainsaw - Won't start


Wally107's Avatar
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09-06-11, 05:10 AM   #1  
Husqvarna 55 Chainsaw - Won't start

Once again, I come before the experts seeking wisdom and advice:

Husqvarna 55 Chainsaw - late 90's vintage I suspect - I inherited it 2 years ago
ZAMA carb: C1Q-EL7

Have always had problems getting it started, but it did usually start.

Now, will only catch about every 10th pull, and then only run for a few seconds...then die.

I will hang my head in shame and admit I stored it over the winter without emptying the fuel...rats!

What I've done so far:

1. (obviously) emptied the tank and put in fresh fuel
2. Cleaned and re-gapped plug (was new last year, maybe has 2 hours on it) - looked OK
3. Tore down the carb. While no expert, I mostly understand the workings of small engine carbs - including the hi & low speed circuits, so I was fairly comfortable disassembling it.
4. Soaked carb body and components overnite in carb cleaner
5. Blew out carb body with compressed air - all passageways appear clear.
6. Re-assembled carb - set hi & low speed needles 2 turns out.
7. Blew compressed air backwards thru fuel line to clear filter - appears OK.
8. Disassembled muffler - spark arrestor screen is clear.

Put it all back together - no improvement. Will catch about every 10th pull, and run for 1-15 seconds...then die.

My next step(s):

1. Replace spark plug (although I don't think it needs it).
2. Replace fuel filter (although it seemed unobstructed when I blew it out).
3. Get carb rebuild kit (although there really isn't much to these, so I'm not sure if it will help).

Any thoughts from the masters?

 
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09-06-11, 07:47 AM   #2  
Get a carb kit & do it right! Those gaskets are too dry to work correctly! 1 turn out both needles & adjust from there!

AJ

 
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09-06-11, 10:14 AM   #3  
Does it rev up good, or are you running it at idle? Hold the trigger to full throttle and as it starts and runs, work the choke quickly to keep it running. Sometimes this will work out whatever trash or restriction that is causing problems.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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09-06-11, 02:13 PM   #4  
Posted By: aj-allen Get a carb kit & do it right! Those gaskets are too dry to work correctly! 1 turn out both needles & adjust from there!

AJ
Thanx aj - I figured a "real" carb rebuild would be the next logical step. I've noticed there are a dozen different opinions on how far out to turn the HI / LOW speed needles, everywhere from 1 turn to 4 turns, and every fraction in between. I started with 2 turns out, then went down to 1 (in 1/4 turn increments - mostly on the LOW needle) - still no luck.

 
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09-06-11, 02:20 PM   #5  
Posted By: cheese Does it rev up good, or are you running it at idle? Hold the trigger to full throttle and as it starts and runs, work the choke quickly to keep it running. Sometimes this will work out whatever trash or restriction that is causing problems.
Thanx cheese. The most it's run is for about 15 seconds, and when I touched the throttle, it died (which told me the LOW speed needed to be adjusted) - but I couldn't get it to run long enough to do any adjustments.

As I'm sure you know, when you pull the choke lever out, it puts it at "high idle" (about 3/4 throttle) - so the few times it did catch, it revved up pretty good - but then died as I tried to touch the trigger.

Anyway - I'll try a rebuild kit, and also replace the fuel filter, so what that does. Wish me luck!

 
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09-18-11, 11:21 AM   #6  
Close, but no cigar...

Finally got a day off, so I re-rebuilt the carb - this time installing all the new parts.

Also replaced the spark plug and fuel filter.

**Backed out the H and L 2 turns**

This time it started fairly easily, and seemed to idle OK.

Let it warm up at idle for 5 minutes, then tried to throttle up. Sputtered and died...which told me to back out the L needle.

Backed it out 1/8th of a turn at a time. Actually got it to improve some, and almost got it to full throttle (I think at about 3 turns out) - but then it sputtered and died. Decided maybe the H was a little lean (although I had just a little whisp of smoke from the exhaust - just a little).

Anyway, tried turning the H 1/8th turns in both directions - if anything, it was worse.

I noticed in the ZAMA adjusting instructions, it says to back out H and L 2 turns...and turn the idle screw (TAS) all the way in. Odd, won't this just flood it right from the start? Anyway, I tried it, and it wouldn't start at all. While I had it idling, I adjusted the idle screw just to where the chain wasn't turning, and kept adjusting it as I played with the L needle.

So here's where I am: Saw will start, and idle. But will NOT smoothly accelerate no matter where I have the L needle. Can't get it to run at WOT long enough to adjust the H needle.

1. Any idea why ZAMA says to start with the idle screw all the way in?

2. What's my next step?

 
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09-18-11, 02:27 PM   #7  
Just went out and played with it some more (now that my 'pulling' arm has recovered), and noticed the following:

- Seems to start and accelerate smoothest with L at 3-1/2 to 4 turns out.
- If I accelerate slowly, it will approach WOT, but seems to 'surge' quite a bit as it accelerates.

Almost seems like I still have a fuel flow issue...but the line is good and clear, and the filter is new.

Hmmmm.....

Also, if I decide to just install a new carburator - do any of you have a secret place to get the best price? Lowest I've seen is $41 from mowers4u.com.

 
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09-19-11, 12:06 AM   #8  
Still sounds like a problem in the carb. They can be darn near impossible to fix sometimes. Replacement is probably the better option if you consider your time. Your quoted price sounds reasonable.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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09-19-11, 11:20 AM   #9  
Thanx cheese. Yup, I've fixed all that can be easily fixed. It may be a problem with the main check valve, which I really don't feel like messing with, so a new carb is probably the smartest route.

 
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09-20-11, 03:19 PM   #10  
A break in the case...

Got to thinking...what would allow it to start, but then stall out, as though it was being starved...hmmmm...

So after a few hours of pondering, and a few hours of surfing, I decided to check the fuel tank vent. Sure enough, it was plugged up tight. Had to take the little strainer thingy off the end, since that seems to be uncleanably clogged, and ran a thin wire thru the tube, and put it back in. Re-adjusted the L & H back to 1-1/2 turns out, and....

Bingo - started on 2nd pull, and ran quite well. Let it warm up, and adjusted the L screw to where I had snappy and smooth acceleration. Adjusted the H screw, but I still need to work on that to get it right.

Was able to make a few 6" dia cuts, but unfortunately, it started bogging again, but not near as bad as it was. This was a HUGE leap forward.

Over the next few days, I plan to:

1. Replace the fuel line - I'm still not 100% sure there isn't a pinhole leak in it.
2. Replace the fuel tank vent assembly - so it's back to OEM standards.
3. Replace the gasket between the carb and cylinder.
4. Double check the impulse hole - another forum suggested this may be clogged/blocked...worth investigating.

I'm fairly certain now the carb itself is OK - it was running fantastic and (initially) had very snappy acceleration. I'll know better once I replace the above items. Will keep ya posted.

 
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09-20-11, 06:41 PM   #11  
That's good! Glad you got it figured out. I would have suspected the tank vent if it ran longer than one to 15 seconds, and didn't take so many pulls to start. Usually the tank vent takes longer to starve the saw, and the starvation becomes gradual at that point. i'll keep this in mind if I run into a similar problem.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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10-07-11, 03:08 PM   #12  
Runnin' like new!

FINALLY got in the parts I mentioned above and just put them in.

YAHOO! Runs like a Swiss watch (and keeps running). Throttle is snappy, hi idle is great - cuts like budda.

I have a feeling the gasket between the carb and the cylinder was the last piece to the puzzle. Even though it "looked" fine, as someone in another forum said...there's no "re-using" a gasket - always replace.

Anyways, I'll close out this thread with many THANX to all who assisted.

Wally

 
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