Tracking a leak

[countryhog]

acquired a jonsered 451E saw. Love how it was built and runs but couldnt be tuned
Tore it down and did a vacuum and pressure test. Squirt soapy solution all over. Aha! The pto seal leaking. Replace seal. Run tests again and still leaking. Spray soap again. Its the freaking modified spark plug; not where i installed the quick coupler into the plug base but where the plug screws into the cylinder. What? Took it out and saw some divits on the mating surface. Filed them down, reinstalled, and pressurized. Problem fixed.Holds vacuum (5 psi for 5 minutes) and pressure (10 psi). Reassemble saw and test cut. Still cant tune. Im thinking its probly the other seal so i tear it down and replace the other seal. Do some cutting and voila! same symptons. Dam. Tear it down and run tests again. Almost holds vacuum but very slowly loses vacuum; after 3 minutes lost 2psi of the 5psi i started at. Neither seal is leaking. Neither is the plug. Start sprayng everywhere. Its the freaking cylinder gasket. Three of the cylinder bolts are tight, one not loose but not even close to spec. Took it apart AGAIN and noticed the three tight bolts have noticeable thread lock and the other does not; someone screwed up. Ordered new gasket. Waiting for delivery. Will let you know how it works out.
What ive learned is to think outside the box.

 

[XP_Slinger]

acquired a jonsered 451E saw. Love how it was built and runs but couldnt be tuned
Tore it down and did a vacuum and pressure test. Squirt soapy solution all over. Aha! The pto seal leaking. Replace seal. Run tests again and still leaking. Spray soap again. Its the freaking modified spark plug; not where i installed the quick coupler into the plug base but where the plug screws into the cylinder. What? Took it out and saw some divits on the mating surface. Filed them down, reinstalled, and pressurized. Problem fixed.Holds vacuum (5 psi for 5 minutes) and pressure (10 psi). Reassemble saw and test cut. Still cant tune. Im thinking its probly the other seal so i tear it down and replace the other seal. Do some cutting and voila! same symptons. Dam. Tear it down and run tests again. Almost holds vacuum but very slowly loses vacuum; after 3 minutes lost 2psi of the 5psi i started at. Neither seal is leaking. Neither is the plug. Start sprayng everywhere. Its the freaking cylinder gasket. Three of the cylinder bolts are tight, one not loose but not even close to spec. Took it apart AGAIN and noticed the three tight bolts have noticeable thread lock and the other does not; someone screwed up. Ordered new gasket. Waiting for delivery. Will let you know how it works out.
What ive learned is to think outside the box.

Great post!

I think we’ve all been there, I know I’ve gone much deeper into a saw than I’ve had to only to find that it was a simple fix like a fuel filter or something insanely easy like that.

 

[Woods Works]

Try pressure testing the carb for leaks also. If its the original tilly HK with separate "sandwich" style metering plate that can warp especially if its the plastic version. I gave up on rebuilding this carb and replace them with a walbro from later 450/525 or 455/535 models. HDA-6 or HDA-52.

 

[countryhog]

Thanks. Will do. Can you point me to a tutorial on carb testing? Seems the hda6 and hda52 are nonobtanium. At least on ebay

 

[Bigmac]

My vote is the carb, if she is holding pressure/vac, I had an 024 that just wouldn’t tune, pressure test/ok carb kit, same problem, put a new carb..fixed!! Just did an 028, wouldn’t start well wouldn’t hold a tune, just threw on an $8 China carb, works great! It was cheaper than a carb kit!

 

[Al Smith]

Okay now a story .Some years ago "TW" ,Brian had a saw he just could not find a leak in .Sent it to Copesy who couldn't find it either .I don't know where this idea came from,probably Big Dave but he sealed it up then used the impulse line to inject it full of air and tossed it in a vat of water .Found it that way .

 

[Woods Works]

This tillitson site has some good info, tho not much specific to the HK series.

The HDA-3 will also fit up to the 451

https://tillotson.ie/resources/

 

[angelo c]

Okay now a story .Some years ago "TW" ,Brian had a saw he just could not find a leak in .Sent it to Copesy who couldn't find it either .I don't know where this idea came from,probably Big Dave but he sealed it up then used the impulse line to inject it full of air and tossed it in a vat of water .Found it that way .

Ive found a few that way , I must say when I have gotten to that point im slightly perturbed though and the nearest hill looks a very close "throw" away.

 

[DSS]

Ive found a few that way , I must say when I have gotten to that point im slightly perturbed though and the nearest hill looks a very close "throw" away.

You prolly need anger management

Just sayin

 

[Bilge Rat]

Anger management is the ability to let go the anger and walk away.
This frees the mind and lowers stress which is good for the heart.

So, if you release the object of your anger at the right time after getting it up to speed with proper arm movement you can fling the dang thing pretty far. This will remove the anger and lower stress. Ask the Doctor he will agree.

I have found that you do need a good landing area that is somewhat soft so after you have calmed down and relaxed the mind, use chemicals if needed you can retrieve the offending object and then fix it.
The issue seems to show itself when you are calm.

When you get older you learn to walk away, get calm then things go better.
Also old age prevents you from throwing things as far and that is why i have over 50 hammers that solve most problems.

I have a Husky 365 that has a slow leak, it is within spec but it bothers me just the same.
The saw runs fine but i can't get that total seal. It bothers me worse than if it were broke.

Your problem is minor, relax buy a few carbs and some new tools you will feel better even if the saw doesn't respond properly.

 

[countryhog]

I pressure tested the carb. Falling. Dipped in water. Leaking out of the pump cap. Tightened real tight. Still leaking. Thought, what i got to lose so put motoseal on gasket surface and retested. Still leaking. Kinda getting pissed so motosealed all interfaces between carb, diaphragm, gasket, lid. Still leaks although much , much slower. Gonna run it tomorrow to see. Not one scratch, gouge, or divit anywhere on the carb face to be seen. Ran straightedge across it. No warpage. So, where can an hda3 be found? No joy on ebay. Such a shame. Really like the saw. Now i know why it was free, ha. Used to like tillies too. At least the ones for larger saws i still do
So what is the spec leak rate you speak of?

 

[angelo c]

You prolly need anger management

Just sayin

Thanks "captain obvious".... !!!!!

 

[Woods Works]

This one will work, buy it or I will just to have for ????

https://www.ebay.com/itm/Jonsered-4...4wAAOSwjIta60X7:sc:USPSFirstClass!54501!US!-1

 

[countryhog]

Been looking at that. Waiting on ring and cylinder gasket so i can reassemble and test it.