How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Curtis B. Your Own Question
Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 26014
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
30244710
Type Your Small Engine Question Here...
Curtis B. is online now
A new question is answered every 9 seconds

I have a husqvarna 435 chainsaw, it will start but when you

Customer Question

I have a husqvarna 435 chainsaw, it will start but when you give it gas it will not go more than half speed, I put new fuel line and filter, installed new carb, new plug, checked spark arrestor, and still will not rev up. I pulled off muffler and checked cylinder walls and didn't see any scoring , I am stuck, what do I need to do around check next?
Submitted: 6 months ago.
Category: Small Engine
Expert:  Curtis B. replied 6 months ago.

Check the throttle linkage and look at the carburetor throttle plate, is the linkage opening the throttle flap fully when engine is OFF. Lack of rpm is typically just the throttle not opening fully.

Customer: replied 6 months ago.
I can see the butterfly through the carb, and it's working properly, I did a compression test on it , got 115 lbs compression.
Expert:  Curtis B. replied 6 months ago.

If compression was problem, it would not start. It starts, so that is ok. You have new carburetor, is it adjustable? Have you turned the high speed screw while throttling it?

Customer: replied 6 months ago.
it is adjustable, I turned the high slowly out while pulling throttle, no change, I turned high screw in slowly, no change, also did same with low screw, I set them back to where they are supposed to be.
Expert:  Curtis B. replied 6 months ago.

If you dribble fuel into the carburetor while running at high speed does it increase in rpm?

Customer: replied 6 months ago.
No actually it doesn't, I tried that, and while I have it running , and adjusting on carb, I see few drops of gas coming from carb.
Expert:  Curtis B. replied 6 months ago.

Did you try running without the muffler/spark arrester?

Customer: replied 6 months ago.
I loosened the muffler while it was running, no change, I even pulled it off, still no change.
Customer: replied 6 months ago.
what do I check next?
Expert:  Curtis B. replied 6 months ago.

When did it last run correctly? Are you using premixed fuel?

Customer: replied 6 months ago.
Well, my customer brought it to me about a week ago, said it was working good and he shut it off, ate, and when restarted it started doing what it's doing now, not wanting to go full throttle, the saw isn't maybe a year old, so I did the carb adjustment, fuel lines, new carb, good gas, ect. That's why I'm puzzled.
Expert:  Curtis B. replied 6 months ago.

Coil is not loose, throwing off the spark/timing?

Customer: replied 6 months ago.
I thought that too, and checked the coil, but it's tight, could it be going out? It looks like it has a good spark,.
Expert:  Curtis B. replied 6 months ago.

I doubt it. That would only leave the timing key on the flywheel.

Customer: replied 6 months ago.
your saying to pull flywheel and check the key? Isn't the key made into the flywheel? Key and flywheel all one piece? . And also wouldn't that make it hard to start with the timing off?
Expert:  Curtis B. replied 6 months ago.

would think it would make it hard to start, but all other items seem to have been checked..

Customer: replied 6 months ago.
I will pull flywheel and check, just doesn't make sense, I thought I might have over looked something.
Expert:  Curtis B. replied 6 months ago.

I'm with you, makes no sense!

Customer: replied 6 months ago.
Well, just pulled flywheel, and all looks good, key in place. The seal kinda looks like it's cracked around shaft. Could that be the problem? The seals?
Expert:  Curtis B. replied 6 months ago.

Crankshaft seals can let air into the crankcase , but is usually shows as hard start.

Customer: replied 6 months ago.
Well I just talked to another technician and he told me he had one do the same thing and come to find out it was the crank seals, he said it would start but wouldn't rev up, said it was sucking air somewhere. Just like this one, I just don't have the pressure test kit to check them.
Expert:  Curtis B. replied 6 months ago.

It may be crankseals . But i personally have never seen crankseals do this.

Customer: replied 6 months ago.
Me either, that's why I'm lost. Usually if the seals go bad, it won't run at all. That's why I was thinking it was something else
Expert:  Curtis B. replied 6 months ago.

Iwill opt out and see if anyone else can add anything. sorry.

Customer: replied 6 months ago.
Ok thanks