Husqvarna 435 wont start driving me nuts

[CEE]

Hi,

 

I write in desperation and you will see why.

 

I have 4 year old Husqvarna 435. It's a low hours engine - maybe 25 hours over its whole life. It has been very carefully loked after, drained over winter, never left in rain, never dropped etc....

It's always started first time.

Now it won’t start. It kind of burns feebly enough to make some smoke while the rope is being pulled and then sometimes fires but only for literally half a blip then dies and makes a bit of oily smoke

the spark plug (brand new) is oily and a bit of oil comes out a bit through the spark arrestor

I consider myself good with engines and maintain a year old 15hp outboard and a 20year old Toyota landcruiser

I have so far: (in this order)

1) changed the spark plug, twice
2) checked that there is a lovely fat blue white spark by grounding it on the case
3) changed the air filter,

4) Left the air filter off to make sure its getting air no  doubts
5) Changed the fuel filter,
6) changed the fuel out for fresh new fuel that makes the outboard run like a train so I know it’s good.
7) Taken out the plug and left it for a day to let any flooded fuel evaporate,

8) taken out the plug, turned upside down and cranked it to make 100% sure any flooded fule runs out
9) Taken off the spark arrestor - it was clear anyway. Left it off for now.

10) stripped and rebuilt the carb
11) Changed the carb out for a new one - not OEM - aftermarket
12) Carefully made sure the L and H on the carb are set to allow a start

13) Made sure there is a couple of extra turns on T to give it a helping hand

14) Taken off the muffler to find that the piston it literally like new, no carbon no scoring

15) taken off the fltwheel to find that the keyway is not sheared so timing fine

16) taken off the whole inlet boot and manifold to make sure that the 'built in' impulse pipe is clear - it (like evwerything else) was pristine

17) Checked that the air purge pumps fuel - it does - so it is drawing fuel up into the bottom of the carb under the membrane

18) Checked all the hoses, they are full of fuel, don't leak and spill the fuel when taken off so they seem to be doing their job

19) checked that the hole in the piston case, the holes in the inlet manifold and the hole in the bottom of the carb that all togther make up the impulse pipe are joined and sealed

20) pulled off the connectors from the 'cutout' switch that ground the coil to stop it running and taped them up so there is no way they can be operating by accident. There is a spark anyay.

21) I know there is good compression on the upstroke becuase it is hard to crank and then gets easy when the plug is out.

22) checked that the clutch is running freely - getting desperate now

23) considered the crankshaft oil seals leaking pressure - looked at them they at least look like new - remember it's a very low use chainsaw.

 

All for absolutely no result.

I am very careful with my mix - I have proper measuring containers and I use a syringe to put in the correct dose of oil. I use the proper expensive Husqvarna oil (like an idiot)

I think that the oily cylinder and plug is a symptom of me pulling it over and over to try start it pumping fuel and oil in rather than the cause

So I am about to smash it to bits with a sledgehammer. I've spent more time trying to fix it than I've used it. I thought Husqvarna was supposed to be a good make.

 

You can get 20 inch bar 'cheapos' for £80 on ebay - it would be easier, chepaer and quicker to do that and then just chuck it out every 2 years.

 

It's like I have a chainsaw that's been cursed.

 

Any help much appreciated,

[Stubby]

19 minutes ago, CEE said:

Hi,

 

I write in desperation and you will see why.

 

I have 4 year old Husqvarna 435. It's a low hours engine - maybe 25 hours over its whole life. It has been very carefully loked after, drained over winter, never left in rain, never dropped etc....

It's always started first time.

Now it won’t start. It kind of burns feebly enough to make some smoke while the rope is being pulled and then sometimes fires but only for literally half a blip then dies and makes a bit of oily smoke

the spark plug (brand new) is oily and a bit of oil comes out a bit through the spark arrestor

I consider myself good with engines and maintain a year old 15hp outboard and a 20year old Toyota landcruiser

I have so far: (in this order)

1) changed the spark plug, twice
2) checked that there is a lovely fat blue white spark by grounding it on the case
3) changed the air filter,

4) Left the air filter off to make sure its getting air no  doubts
5) Changed the fuel filter,
6) changed the fuel out for fresh new fuel that makes the outboard run like a train so I know it’s good.
7) Taken out the plug and left it for a day to let any flooded fuel evaporate,

? taken out the plug, turned upside down and cranked it to make 100% sure any flooded fule runs out
9) Taken off the spark arrestor - it was clear anyway. Left it off for now.

10) stripped and rebuilt the carb
11) Changed the carb out for a new one - not OEM - aftermarket
12) Carefully made sure the L and H on the carb are set to allow a start

13) Made sure there is a couple of extra turns on T to give it a helping hand

14) Taken off the muffler to find that the piston it literally like new, no carbon no scoring

15) taken off the fltwheel to find that the keyway is not sheared so timing fine

16) taken off the whole inlet boot and manifold to make sure that the 'built in' impulse pipe is clear - it (like evwerything else) was pristine

17) Checked that the air purge pumps fuel - it does - so it is drawing fuel up into the bottom of the carb under the membrane

18) Checked all the hoses, they are full of fuel, don't leak and spill the fuel when taken off so they seem to be doing their job

19) checked that the hole in the piston case, the holes in the inlet manifold and the hole in the bottom of the carb that all togther make up the impulse pipe are joined and sealed

20) pulled off the connectors from the 'cutout' switch that ground the coil to stop it running and taped them up so there is no way they can be operating by accident. There is a spark anyay.

21) I know there is good compression on the upstroke becuase it is hard to crank and then gets easy when the plug is out.

22) checked that the clutch is running freely - getting desperate now

23) considered the crankshaft oil seals leaking pressure - looked at them they at least look like new - remember it's a very low use chainsaw.

 

All for absolutely no result.

I am very careful with my mix - I have proper measuring containers and I use a syringe to put in the correct dose of oil. I use the proper expensive Husqvarna oil (like an idiot)

I think that the oily cylinder and plug is a symptom of me pulling it over and over to try start it pumping fuel and oil in rather than the cause

So I am about to smash it to bits with a sledgehammer. I've spent more time trying to fix it than I've used it. I thought Husqvarna was supposed to be a good make.

 

You can get 20 inch bar 'cheapos' for £80 on ebay - it would be easier, chepaer and quicker to do that and then just chuck it out every 2 years.

 

It's like I have a chainsaw that's been cursed.

 

Any help much appreciated,

The only thing that stood out for me was number 6 .  Out board mix is different . Something to do with the oil being different because of the water cooling on an out board . I would not use out board mix in a chainsaw .  Other than that a very comprehensive test . I would have sent it to spud by no 8sih ! ☺️

Edited September 23, 2020 by Stubby

[CEE]

Thanks Stubby. The outboard is just mised with regular 2 stroke at 50:1. I did have 40:1 in it before with the expensive husqvarna oil.

 

I think it might be enough to make it grumble but not kill it completely.

 

My current guesses are either the impulse tubeway still isn't holding pressure - in fact I am surprised that it's a pipe of 3 or 4 bits of metal that seem to be just 'pressed togther' seems plenty of scope to go wrong. OR the aftermarket card is also sh*te and I've got 2 carbs on the blink unlikely but possible....

 

Husqvarna you are going down in my opinions very fast.

[CEE]

actually I lie. I have 50:1 in it now with ordinary 2 stroke. I used to run it also on 50:1 with the husky oill too - as per instructions.

 

The destruction manual says drop to 33:1 if you use regular 2 stroke so I could do that but I know that isn't enough to do this to it.

[joshuatree]

1 hour ago, CEE said:

Husqvarna

Found the issue for you. ?

[Chrisdisco]

I'm by no means an expert but I did have saw once that has a similar issue. Turned out replacing the coil fixed it. It seemed that there was a break in the lead that tested fine when the plug was out, but wasn't connecting right when on the plug.

 

Might be worth a go.

[gary112]

been using Husky 435s for years for hedge laying but the last couple have not been so good so just bought this from Shavey (on here)and so far its a great little saw far better than the 435 

[CEE]

yes it might be worth a try coils are cheap

 

it has to be SOMETHING right?

[CEE]

Actually I have a lot of Makita tools, grinders, circular saws, SDS drlls etc.. all are very good but I have a Makita orbital sander and it's absolute crap.

[CEE]

ive actually ordered another new carb

 

It's not such a long shot:

 

I know fuel is in the bottom of the carb - you can see the bulb pulling it through.

I know air is going into the engine.

I know that there is a spark (but i've ordered a new coil just in case) The existing coil tests at 0.5 homs so it's bang on spec

I know the timing is OK becuase the keyway is intact

 

So I only need compression / vacumm under the piston to go along the umpulse pipe and for the carb membrane to do it's job and pump the fuel.

 

I think it's hugely unlikely that the crank seals have gone (but i will go there if needed)

 

if the crank seals are intact then there is pressure in the impulse pipe and fuel should pump

 

so it's back to carb

 

Let's assume that the original one went wrong / got clogged - it wasn't the best in the work when I reconditioned it. Maybe my clean out didn't work.

Then the new aftermarket one I bought had 4/5 stars on Amazon so lets assume that 10% of the carbs they sell don't work

 

I really could have 2 duff carbs - it's not 'that' of a long shot

 

So another new carb coming....