Cutters edge 670 (jonsered 670) idle issue?

[Gunn]

Gents this saw has exhausted my limited knowledge, if anyone has any additional tips or suggestions I'm all ears.

Symptoms: saw will not idle. It starts on choke, idles for roughly 15 secs then leans out and dies. It will restart if choked but repeats the above.

What I have done so far:
1 pressure and vac tested- passed no issues.

2 replaced fuel line and impulse line- they were rotten.

3 ran carb (Tilly 23hs) through ultrasonic multiple times and rebuilt with new kit.

4 checked metering lever- flush with carb body

5 replaced fuel filter

6 cracked open fuel tank after it dies to test vent but doesn't seem to matter.

To me it acts like its starving for fuel. Compression is stout and piston and cylinder look pristine.

If anyone has suggestions they would be appreciated.

Thanks!

 

[Motorhead]

Open the L needle half a turn,I use a shop vac on my carburetors to make sure I don't force gunk deeper into the carb.

 

[Gunn]

That was something I tried earlier. I think I ended up around 2 turns out from seated on the L without much change.

 

[Motorhead]

Recirculating carburetor?

 

[Simondo]

Well if the case is not giving you a air leak or any other parts ...impulse, fuel lines, carb gaskets and the carb is clean and L-H jets were pulled ? then i would suggest it may still be down to starvation of some sort. Impulse rotten...did you blow through onto the crankcase ? Have you checked the fuel line for kinks in the tank ? I Would say its still not pulling through from the tank with the impulse (Gaskets and diaphrams the right way up in order ? ) or the internals of the carb are not letting it into the intake somehow. Thats My best guess from your description.

 

[Gunn]

Yep, pulled the whole carb apart (needles included) when running through the USC.

The fuel line isn't kinked, it just feeds straight up through the tank into the carb box similar to a 372.

I replaced the impulse with a new line but did not check the impulse port on the cylinder. I'll give it a shot of compressed air to see if it's partially plugged or something.

 

[Gunn]

Recirculating carburetor?

Nope, 23hs on this one.

 

[lwhaples]

Had a 670 that ran fine until the cover was tightened down.The cover was closing off the impulse hose. Had to cut a notch for the hose to be happy.Not to say this is your trouble. Will be interested to read how it gets fixed.

 

[cus_deluxe]

i have an ms290 thats doing basically the exact same thing (leans out majorly when it warms up a bit and dies) and im convinced its a minor air leak that gets worse as it warms up. it had VERY minor pressure and vacuum loss after a few mins cold, but slightly more when warm. id try to test it with another carb and if that doesnt work id look real hard for an air leak.

 

[Gunn]

I've got a couple solid things to check tomorrow.

 

[huskihl]

Low circuit is still plugged on the carb. Will it Rev up?

 

[MERR6267]

I had a 670 that had idle issues as well.
After playing around with all kinds of stuff and replacing seals, hoses, filter, etc I ended up replacing the tank vent. That was causing the tank to develop vacuum and the carb wouldn't pull fuel.

I also had an issue where the idle was too rich, and after setting it down to idle it would simply stop running and not want to restart without setting the high idle and pulling like mad. more than a few seconds at idle would puddle the fuel and basically create a "flooded" situation.

 

[Gunn]

I tried running it without the top cover to verify the cover wasn't pinching the impulse line and checked the impulse port to verify it wasn't plugged. It still acted the same.

Does anyone have a spare carb they'd sell me?

 

[Mag Craft]

When you vacuum tested did you check it with the intake in place. The rubber intake boot on those over time can get stiff and hard and lose the seal they make at the carb end. Unfortunately the intake boot is NLA.

 

[Gunn]

I blocked off the muffler and slipped rubber between the carb and intake. The boot did leak slightly but tightening the clamp seemed to take care of that.

 

[jmssaws]

Sounds like the fuel line is kinked to me.
I've had new fuel line with a hole in it also.

 

[huskihl]

I tried running it without the top cover to verify the cover wasn't pinching the impulse line and checked the impulse port to verify it wasn't plugged. It still acted the same.

Does anyone have a spare carb they'd sell me?

Bplust is my first guess as a source for one. If not, I'd buy a knockoff hs260a off a 272xp from eBay and change the shafts to retain the high idle function

 

[Gunn]

272 carb pulses through the intake, the 670 has an impulse hose. I'm not sure my neighbor wants to go through the conversion.

 

[huskihl]

272 carb pulses through the intake, the 670 has an impulse hose. I'm not sure my neighbor wants to go through the conversion.

If it's a tilly knockoff, 670 top plate will go on the other carb with a smear of silicone over the old pulse hole. 15 minutes to do the shafts. Or maybe get lucky and find a replacement for $85.

 

[Motorhead]

Question,Did you change the Welch plugs