Husky 435 X-Torq Compression question, hot starting issue

[Bama Raised]

For some time now I have been having an issue where my 435 is very difficult or impossible to start when it is hot, but only if it has sat for a couple of minutes and has become "heat soaked". It will start back up as long as long as it doesn't sit for any period of time. I have replaced all of the fuel lines, bulb, and even the intake boot. The carburetor has also been completely rebuilt and cleaned. Spark plug is tan as well. Still, the problem persists.

So I decided to purchase a compression tester and ended up getting a reading of just over 115 PSI cold. Does anyone know what the compression should be for my saw when it is cold? Could my compression possibly be dipping low enough when the saw is hot to cause the hard starting issue? I have loss noticed a loss of power in the cut as well. When I rebuilt the carb I removed the muffler s well to inspect the piston, it looked good with no scoring. Any help would be appreciated, thanks in advance.

 

[Andyshine77]

Does the end of the compression gauge hose have a valve in it? Did you keep pulling until the needle stopped climbing?

If that reading is correct you have problems it should be at least 130 usually quit a bit more.

 

[Bama Raised]

Does the end of the compression gauge hose have a valve in it? Did you keep pulling until the needle stopped climbing?

If that reading is correct you have problems it should be at least 130 usually quit a bit more.

Yes it has a valve in it. I kept pulling until the needle stopped climbing, probably 5-6 pulls in total. I believe the gauge is accurate, because I have tested other things with it, including my 460 Rancher (which runs great) and it came in around 150 psi. I did some searching, but I never could find an answer in regards to what a healthy compression range is for a 435 x-torq.

 

[champion221elite]

I have a healthy 435 x-torq saw at home. I'm at work now but will check it when I get back.

 

[MaddBomber]

115psi cold is definitely low. Warm the saw up, make a few cuts then immediately test it again, so its at operating temp. I bet that's your problem.
Those little 35cc saws get themselves in over thier head quick. Wood that's too large really beats on the top end. Plus the carbs come pre-set on the lean side for EPA standards.
Pull your muffler and check your piston through the exhaust port. I'm thinking a new piston is needed, in which case a new saw will probably be cheaper.

 

[champion221elite]

Just checked my 435. Its blowing 135 psi cold with the throttle fully open. I'm using an OTC compression gauge without an adapter. Its currently 30 degrees in my area. Not sure about the 35cc comment. The tag on my 435 says it's a 41 cc engine.

It's a 2018 model with 4-5 tanks of fuel so far. Probably still breaking in a bit.

 

[MaddBomber]

Not sure about the 35cc comment. The tag on my 435 says it's a 41 cc engine.

My bad, I was thinking about the 235e. Same still applies, as they're easy to burn out.
The 142/435 are great little saws that are feather-light and high rpm. But, anything more than pruning, and the fuse is lit.
I've rebuilt more 35-45cc clamshell saws than anything else. Husqvarna, Stihl, Echo, Homelite, Craftsman, Poulan, they've all burnt up the same way. Usually old timers on a fixed income that can't afford more, but use them to process 10 cords of wood.
Compression goes, or they overheat and damage the crank seals.

 

[champion221elite]

My bad, I was thinking about the 235e. Same still applies, as they're easy to burn out.
The 142/435 are great little saws that are feather-light and high rpm. But, anything more than pruning, and the fuse is lit.
I've rebuilt more 35-45cc clamshell saws than anything else. Husqvarna, Stihl, Echo, Homelite, Craftsman, Poulan, they've all burnt up the same way. Usually old timers on a fixed income that can't afford more, but use them to process 10 cords of wood.
Compression goes, or they overheat and damage the crank seals.

Good to know. I just grabbed a used 435 from here on AS. Compression is 110. I planned on tearing into it and seeing what it needs. I planned on a new piston and jug along with new seals. Hoping the bearings are still good.

 

[Bama Raised]

115psi cold is definitely low. Warm the saw up, make a few cuts then immediately test it again, so its at operating temp. I bet that's your problem.
Those little 35cc saws get themselves in over thier head quick. Wood that's too large really beats on the top end. Plus the carbs come pre-set on the lean side for EPA standards.
Pull your muffler and check your piston through the exhaust port. I'm thinking a new piston is needed, in which case a new saw will probably be cheaper.

Will do. When I was randomly replacing parts trying to solve the hot start issue, I did check the piston and it didn't have any scoring. That's why I originally dismissed compression as an issue. Could it be a bad ring? I'll warm it up and see what kind of a reading I get this evening, i'll pull the muffler and check the piston again as well. Like you said, it's a great little lightweight saw for trimming limbs ect. I'd like to get it back running at full strength. Thank you for the info.

 

[Bama Raised]

Just checked my 435. Its blowing 135 psi cold with the throttle fully open. I'm using an OTC compression gauge without an adapter. Its currently 30 degrees in my area. Not sure about the 35cc comment. The tag on my 435 says it's a 41 cc engine.

It's a 2018 model with 4-5 tanks of fuel so far. Probably still breaking in a bit.

Thank you! I'm glad to know what compression should be on a healthy one now. I searched for a good bit but never could find a definitive answer on that.

 

[Bama Raised]

I was able to do another compression check while the saw was hot this evening, and my reading came in at right around 100 psi. I went ahead and removed the exhaust to check out the piston. I will attach some pics.

 

[Andyshine77]

In the last two pics it's hard to tell exactly what I'm seeing. That said I see what looks like carbon issues, the residual oil is sure dark and some buildup as well. The piston skirt look fine mostly, at least on this side of rhe piston. If 100psi is right something is going on that we can't quite see. Does the saw feel like it has low compression when you pulled over? I also think I see some carbon scoring on the upper left of the piston. I'm guessing some old nasty fuel mix was ran through that saw.

Probably time to pull her apart and inspect things proper.

 

[Bama Raised]

In the last two pics it's hard to tell exactly what I'm seeing. That said I see what looks like carbon issues, the residual oil is sure dark and some buildup as well. The piston skirt look fine mostly, at least on this side of rhe piston. If 100psi is right something is going on that we can't quite see. Does the saw feel like it has low compression when you pulled over? I also think I see some carbon scoring on the upper left of the piston. I'm guessing some old nasty fuel mix was ran through that saw.

Probably time to pull her apart and inspect things proper.

I over adjusted the carb a little before running it today, so it was running rich. Some of what you are seeing is residual oil but the piston is also discolored near the top. The pull did seem a little soft, while it was hot at least. It's difficult to tell when cold. I'm considering stripping it down in the next couple of days. It will be my first time doing that, so we will see how it goes. lol

 

[Andyshine77]

The oil is too dark looking, probably from the carbon washing off. From what I see and what you're saying, it's time to dig into her.

Looks like a low hour saw, are you keeping the mix fresh, chain sharp and air filter clean? Make sure the spark arrestor is clean too.[emoji111]

 

[Bama Raised]

The oil is too dark looking, probably from the carbon washing off. From what I see and what you're saying, it's time to dig into her.

Looks like a low hour saw, are you keeping the mix fresh, chain sharp and air filter clean? Make sure the spark arrestor is clean too.[emoji111]

A family member of mine was the previous owner of the saw. I know he was running regular 87 with 10% ethanol through it, so I am going to go out on a limb and say that it has probably had stale gas ran though it before as well. I have since switched over to 93 octane with no ethanol. Any idea what caused all of that carbon buildup? When I got the saw I inspected the plug, and if anything, it had been running a little lean. The arrestor is clean. When I got it the air filter was dirty and it had dust in the carb, I took care of all that. Chain was on the dull side as well, so i expect it had been ran that way some. Overall the saw just had not been maintained very well at all, even with the low hours.

 

[Andyshine77]

A family member of mine was the previous owner of the saw. I know he was running regular 87 with 10% ethanol through it, so I am going to go out on a limb and say that it has probably had stale gas ran though it before as well. I have since switched over to 93 octane with no ethanol. Any idea what caused all of that carbon buildup? When I got the saw I inspected the plug, and if anything, it had been running a little lean. The arrestor is clean. When I got it the air filter was dirty and it had dust in the carb, I took care of all that. Chain was on the dull side as well, so i expect it had been ran that way some. Overall the saw just had not been maintained very well at all, even with the low hours.

Well we have our answer as to what happened to the saw. Alone any one of the things you mentioned can do lasting damage.

The poor fuel mix and dust ingestion will cause carbon buildup. And if the carb wasn't functioning properly the tuning was off as well.

 

[Bama Raised]

Well we have our answer as to what happened to the saw. Alone any one of the things you mentioned can do lasting damage.

The poor fuel mix and dust ingestion will cause carbon buildup. And if the carb wasn't functioning properly the tuning was off as well.

Is there a chance that the cylinder or piston would be salvageable in this situation? Or is that something I wont know until the saw is torn down? This would be my first attempt at a rebuild, so i'm not really sure how to identify what needs to be replaced, or what can be reused. Is there an effective way to clean up all of that carbon buildup? I appreciate the help.

 

[Andyshine77]

Is there a chance that the cylinder or piston would be salvageable in this situation? Or is that something I wont know until the saw is torn down? This would be my first attempt at a rebuild, so i'm not really sure how to identify what needs to be replaced, or what can be reused. Is there an effective way to clean up all of that carbon buildup? I appreciate the help.

Carbon is pretty easy to clean up, plastic scraper, Scotch-Brite even a piece of wood. Break parts cleaner is also your friend.

You won't really know what you have until you pull things apart. Sometimes all you need to do is clean things up and put a new ring on the piston. Let's wait till you have a better look at things.

 

[Bama Raised]

Carbon is pretty easy to clean up, plastic scraper, Scotch-Brite even a piece of wood. Break parts cleaner is also your friend.

You won't really know what you have until you pull things apart. Sometimes all you need to do is clean things up and put a new ring on the piston. Let's wait till you have a better look at things.

Sounds like a plan. I'll try to get this thing torn apart within the next 2-3 days to inspect everything, and take a few pictures. Maybe that will give you guys a better idea of what all needs to be done. I'd like to thank everyone for all the help so far.

 

[champion221elite]

I plan on tearing into my second 435 on Monday. Maybe we can learn something together.