Husqvarna 55 chain wont stop and saw shuts off

[andrew frazee]

Bought a Husqvarna 55 used ran a couple times fine. Now when it starts the chain spins fast with no throttle . Tried to cut with this condition and it has no power in the cut. No idle or carb adjustment will stop it. Adjusting the carb to far just shuts the saw off. I thought the clutch spring was bad so I replaced it. Didn't fix the problem. Amish guy pulled the muffler and said my piston was the problem. My piston had very minor marks but I took his advice and put a new piston and cylinder in it. Started the saw fine and the chain still spins fast and when I pressed the throttle the saw shuts off again. After the saw starts once it is impossible to start unless it sits for a half hour- like its flooded. I stuck my compression tester in the spark plug hole and then you cant pull the starter rope because its locked. It only pulls with the plug in it. Do you think a carburator gasket repair kit will fix this problem?

 

[CTYank]

Sounds like a major air leak. Like engine speed will not drop to a normal idle, thus the chain won't stop.

Vac/press test should find the leak(s). Not knowing the saw's history or having a clear picture of its current condition, we need pix. Besides the leaks, it very likely needs fuel lines and carb rebuild (not just swap parts).

Much better to find the source of problems than to swap the parts it damaged. If they were damaged. Much more cost-effective too.

 

[dougand3]

I stuck my compression tester in the spark plug hole and then you cant pull the starter rope because its locked. It only pulls with the plug in it.

That's curious. Is the gauge adapter thread longer than plug screw thread? Only way that makes sense is for piston to be hitting the bottom of the gauge adapter.

 

[RiverLogger]

Andrew- How did the rubber impulse grommet look when you took the partition off to change the cylinder? Did you get a new grommet? This is a very typical "leak" spot along with the rubber boot that connects the partition to the cylinder. I usually use a little grease on both of these fittings when installing. I would almost bet your leak is in either of those spots but as suggested above a complete pressure/vac test is in order.

 

[AKDoug]

Another common issue is the carb screws stripping on the plastic manifold on this saw.

 

[andrew frazee]

Ok, I'll look into those things. The saw is in good condition otherwise. The rubber impulse grommet did look a little rough when I transferred it to the new cylinder. The larger rubber boot that connects the cylinder to the partition looked better. I may have used too long of an adapter to do the compression test which caused it to hit the piston. Do you think that the crank seals could be causing a problem like this? I know a pressure test is the way to go. If the pressure test shows a leak, how do you know where the leak is coming from?

 

[sunfish]

Bad air leak likely & possibly roached the new P&C because of it...

 

[AKDoug]

Ok, I'll look into those things. The saw is in good condition otherwise. The rubber impulse grommet did look a little rough when I transferred it to the new cylinder. The larger rubber boot that connects the cylinder to the partition looked better. I may have used too long of an adapter to do the compression test which caused it to hit the piston. Do you think that the crank seals could be causing a problem like this? I know a pressure test is the way to go. If the pressure test shows a leak, how do you know where the leak is coming from?

I use a spray bottle of soapy water. I spray the crank seal, intake system and around the base of the cylinder first. If this doesn't show a leak, I have a large Rubbermaid tote that I fill full of water and dunk the whole saw in to see the leak.

 

[zogger]

55 rancher? If so, my local husky wrench told me he had a bunch of them leaked at the intake.

 

[RiverLogger]

I'd say there is a 99% chance that this saw is leaking somewhere at the intake system. These 55s are notorious for intake issues. Do yourself a favor and buy all new intake rubbers even before you pressure test it, this will eliminate them as an issue and may very well take care of the problem. They should have been changed anyway. How did the partition tighten up? As AKDoug mentioned this is another area of concern.

 

[muddstopper]

I have built a few of those saws lately. Not at all uncommon for air to leak around the partition between the carb and the cyl. New ones are around $10-$12, I have reused the little rubber grommet around the pulse tube several times without any issues. Most likely problem is stripped screws holding the carb on. Anything much more than finger tight will strip those plastic parts. First 55 I built, I used gasket sealer between the carb and partition because the screws didnt tighten as I thought they should. Saw lasted about 15 minutes before it scorched the piston. New piston and new partition and the saw now runs like new. Second saw I found some larger screws to mount the carb with and that fixed the air leak. Last saw, got a New OEM top end and I bought a new partition before I even tore the saw down, didnt want to chance burning up another topend. Carb kits are also pretty cheap, about $8-9 for a kit.

 

[Cliff R]

I've worked on dozens of 55's over the years and never once had an intake leak with one of them. I keep hearing that they are known for this issue, but a little common sense working on them and not putting 50ft lbs torque on the carb screws would be a good idea.

Anyhow, looking at the piston is NOT a good evaluation to replace the P/C. One of my closed port 55's looks like you took a meat grinder to the exhaust side of the piston as it was lean seized when I bought it over 10 years ago. I cleaned it all up and it's been flawless ever since and has 160 psi compression. Most likely the P/C removed from your saw was fine only having "minor marks" in it. If it was a factory P/C it was also probably a much higher quality part that an aftermarket P/C if you went that route? I shy away from the cheaper aftermarket P/C's here, and prefer OEM even at a much higher cost. I don't like doing these things more than once, and aftermarket P/C's are all over the map for quality control especially for the 55's.

Always do a compression test to evaluate P/C damage in addition to a visual look into the exhaust port.

Also a very good idea to vacuum/pressure test the crankcase as well, especially if you are having running issues and lack of control at idle speed and the intake system is well sealed up.

During re-assembly install new gaskets and seal for the intake system, and make sure the screws hold well in the plastic as mentioned above.

Always a good idea to kit the carb and replace the fuel line at the same time, cheap insurance and you've covered the areas that will give issues once it's placed back in service to make sure you don't smoke the new P/C......Cliff

 

[muddstopper]

I've worked on dozens of 55's over the years and never once had an intake leak with one of them. I keep hearing that they are known for this issue, but a little common sense working on them and not putting 50ft lbs torque on the carb screws would be a good idea.

Buying flea market saws you never know who has been torqueing the carb screws. Every single 55 I have picked up has had the carb screws over tightened. Most where running saws, just not carb adjustable because of the air leaks at the partition. Some saws just got a cyl cleaning and a new ring, and others new top ends. The OEM PC kits are now around $100, in some cases less that the china replacement P/C, So cost of new OEM over China isnt the issue it once was, unless your buying the $25 china kits. And I have heard good and bad about those. I burnt up the first $25 kit I bought because of a partition air leak. My personal 55 I bought new hasnt had a problem with the partition screws, but did have a fuel line get pinched causeing running issues. .

 

[71dart]

Those intake bulkheads get kinda pricey when you have to replace every other one you come across. A heli-coil is a cheap and effective fix. A guy named David Young has a video on youtube 'husqvarna 55 intake repair'.

 

[muddstopper]

I have used helicoils before, but not in thin plastic. The coils are cheap enough, but you pay 20 bucks for the tool to install them with. A couple of oversize screws at the hardware store works well and is a lot cheaper

 

[tomdcoker]

Andrew- How did the rubber impulse grommet look when you took the partition off to change the cylinder? Did you get a new grommet? This is a very typical "leak" spot along with the rubber boot that connects the partition to the cylinder. I usually use a little grease on both of these fittings when installing. I would almost bet your leak is in either of those spots but as suggested above a complete pressure/vac test is in order.

My thoughts exactly. Tom