Husqvarna 435 Chainsaw: No Start When Hot Fix 

So to save me standing in my driveway for 30 minutes watching someone chat about almost everything apart from the saw can anyone summarise what we actually wrong with it and how it was fixed?

Vapor lock put cool fuel and it will fix it. Try puting aluminum metal tape in between the motor and the carb to insulate the heat. Just a little piece it will do the trick. Is all plastic with no heat shield

Thanks Tom good video

Great video bro!

I gotta tell ya, That was a LOT of video about everything but the problem and how to fix it. Even watching to the end, I don't know what to do with mine. I'll clear the vent and see what happens.

I am having the same problem with a brand new 550xp mark II that has less than 1 tank of gas going through. Pumping the bulb won't fill it up and fixes itself when cooled off. Also when it's cooled the bulb filled itself.

Clean vent

Really you need to buy several new vents because you’ll need them 😊

Nice vid. Can understand your dilemma(s) with the Brake-down-o-matic saw! Have one myself. If you don't mind... where is place you are chopped down all that oak and spritzing all that urushiol you-rush-she-ol?

Coils are matched to the flywheel (of which there are at least 3 types for this model chainsaw as far as I know) Numbers for the flywheel are cast or stamped on the inside of it (so flywheel off to see which one yours has to find out which ign unit yours has to have) flywheel 580279801 uses ign units - 579638801, 579638802, 579638803, 579638805 flywheels 544874201-544874202 uses ign units - 505427201, 504571401, 573935701, 573935702 flywheel 580279801 uses ign unit 579638804 I believe you cannot mix and match ign units and flywheels - otherwise they either don't run - or will run ...but like shit (I only know this as I bought my 435 second hand and turned out to be a very unhappy saw and the coil was high on the suspect list - but turned out to be mainly carb related and leakdown issues - didn't help that it had lost a screw that holds the barrel on - hidden underneath so not easy to spot - other 3 were not torqued...and leaky fuel lines) Mine now runs like a top, and has been 100% reliable since...not finished watching your video - only got as far as the knocking of the coil being junk based on its origin, so apologies if you did find out which yours needed and sourced the right one (though I know I couldn't find a cheap overseas coil that mine needed based off the flywheel- only the genuine's - which thankfully I didn't actually need in the end) Will watch the rest of your vid hoping you got it nailed in the end :D

Some years back I bought a new Husqvarna 435 Chainsaw with the same problems it pissed me off so many times I gave the fucking thing away. I really did, Never will I buy a Husqvarna again after that. The Husqvarna 435 Chain saw is a piece of shit there's no getting around it $350 out the fucking window. I wouldn't sell it to anyone with a problem in it like that.

As I watched this I made a few comment notes about what I was noticing. By the time I reached the end I deleted those notes. I realized you Appeased yourself and became convinced the saw is suffering a Heat related Vapor Lock issue. Perhaps Heat abuse is increasing the likelihood of a no start when hot, however under normal use you should not be experiencing excessive Heating or a no start. Both Excessive heating and No start can be caused by several different issues or a combination of issues. * I can only offer this one reference as one of those possibilities. You seemed to never address Fuel Flow, or lack there of. This can only be determined by careful mapping of the Fuel system, including the Carburetor(and surrounding Seals) Note - Coil was a reasonable guess, they do Fail under heat and can work fine when cooled off. You mentioned a suspected Lean Condition, and seemed to be on the right track but were weak on confirmation. a) Hot no start, Pump the Purge bulb(it is not a primer) to draw fresh fuel through the Carburetor. Attempt to Start. 1) If no Start, immediately Check for Good Spark.(don't just throw a coil at it) Carry a Multi-meter during testing. a Coil is simple to-read and confirm.(Ohms readings) 2) If Saw starts but shuts off or stalls as soon as trigger is pulled Remove and inspect Plug. very wet = Flooding Damp = normally no fire Dry = Not receiving Fuel to maintain ignition If the Plug is Dry the Carburetor is almost certainly moving enough Fuel - Extremely lean and should be thoroughly inspected. A simple starting point is opening the L/H jets 1/8-1/4 turn to compensate for excessively warm weather(Heat) Inside the Carburetor you may fine a Diaphragm is stiffening(not moving enough fuel) or the Screen cup is restricted with trash(restricting flow) * I never order a new Carburetor or an overhaul kit before completely disassembling, inspecting and cleaning the original. Often a good Flush and adjustment resolves the issue. Inspection confirms if parts are needed(or replacement). Careful adjustment resolves and lean/Rich running issues. b) Fuel System Testing - An inexpensive vacuum/pressure hand pump can test the Fuel Tank/Lines/Purge Bulb/Vent and confirm proper working order. ***** Vapor Lock***** An interesting term but one I would readily dismiss as a oversight in small two stroke engines. Normally Vapor Lock is associated with Metal Fuel Lines. The only thing Metal in a Chainsaw Fuel system is the Carburetor. If all passages are clear and properly open the Purge Bulb should flush the Carburetor with fresh cooler liquid fuel. * If the Purge will not pump Fuel. 1) lay the saw on its side and open the Tank Cap. Pump the Bulb and confirm function. With the Cap open the Tank is 100% venting and fuel should flow freely. 2) with the Top Cover off, fuel lines exposed, pump the Bulb. if it is in good condition and not filling check the return line for Bubbles moving back and forth. Also check the Supply line for Fuel/Air. a) if the supply line has Air trapped and there is movement in the Return line(bubble movement) the Filter is Blocked or possibly a kinked/collapsing supply line. b) If the Supply line is Fuel Filled and the Bulb is moving bubbles the Carburetor is likely restricted/Blocked. *********** Bubbli(ng in Tank*********** That concerned me. (If) the bubbling was coming from the Vent, air entering to balance Tank pressure, it should have stopped instantly when the Cap was removed. The exact spot the bubbles were coming from needed to be identified as Air Pressure was being relieved from somewhere and the Carburetor seems to be the only likely culprit.(Supply/Return?)

Nice story line...Lots of mystery, suspense and some twists. Ignition coils...Why does an ignition coil go bad? Typical thought in a persons head when they discover there's not any spark is, "It worked last time I used it." So, why did it go bad when you were not using it? My current theory, (past 3 years) is shorting any electrical equipment to ground is not good. Nope. Breakers, fuses resistor fuses...tend to trip, blow and/or fry. So why is the off switch, actually an on switch, that connects/shorts the coil to ground? I choke my engines off now. But yeah...quality control is very foreign to some countries....companies...management. How hard could it be to 3D print a coil case and use the same core, new/better wire? Okay...15:24...time to find what happens and who dun it?

It's vapor lock

i wish i could hear you talking....the log splitter is about all I hear

Husqvarna chainsaw's i dont buy no one they are money wasted