660 help please!

[willis09r]

My new to me but used 660 just won't run right. Any help would be much
appreciated before it has to go to the dealer for an arm and a leg per hour.

2 light scoring marks on piston but has 160 lbs compression.

It will pop on choke and then start on fast idle but will not idle unless I feather the gas. New carb kit. Same thing. After many carb adjustments, I finally got it to idle on its own, but if I blip the throttle it revs quickly up and down on its own. I assumed (with no real knowledge) there was some sort
of air leak causing this erratic revving.

Find a crack in the intake boot, so new intake boot and still the same thing.

Other notes: No problem at all to get started, but it will only start if I pop it first on choke and then start it on fast idle. Will not start in the run position. It revs high and fine but dies off like a turd. I can not pressure/vac test myself but if this is my next step, will pay to do so. Impulse line, fuel line, tank vent show no visible signs of failure.

I might have thought I jacked up the carb kit install, but it acted the same before and after the new kit.

Thanks!

 

[JohnnyBoy1986]

vacuum/pressure test the saw next to check for air leaks elsewhere. make positive your fuel and impulse lines are good and if all else checks out well, IF you can borrow a used carb or try one off another saw i'd check that, i've chased many "air leaks" before and only to find out my carb was junk. live and learn. I hope something turns out soon. remember, check and double check alllll the basics first. then we can move onto the major stuff.

 

[logging22]

vacuum/pressure test the saw next to check for air leaks elsewhere. make positive your fuel and impulse lines are good and if all else checks out well, IF you can borrow a used carb or try one off another saw i'd check that, i've chased many "air leaks" before and only to find out my carb was junk. live and learn. I hope something turns out soon. remember, check and double check alllll the basics first. then we can move onto the major stuff.

:agree2::agree2:

 

[willis09r]

If it currently has a Walbro carb on it, will other 660 carbs fit?

In other words, before I bid on this 660 carb ending in 50 minutes with
no description will it fit it isn't the same one i currently have on mine?

 

[teacherman]

If the seals are good, and you wish to use the existing carb, you can take it apart and put it in an ultrasonic cleaner. It is very good at cleaning carbs. Recent threads cover this rather well. Good luck.

 

[stihlboy]

If it currently has a Walbro carb on it, will other 660 carbs fit?

In other words, before I bid on this 660 carb ending in 50 minutes with
no description will it fit it isn't the same one i currently have on mine?

hold on, i know where i can get you a carb.

let me call him

 

[willis09r]

Fred did you find me one? I still have those leftover parts I could ship ya too!

 

[willis09r]

One last cry for help before it goes to dealer just in case someone that
may know something missed this thread before. :help:

Only update is that I've rebuilt the carb again, checked and double checked
every basic thing I could check. (Lines, comp., plug, filters, screen)

Now I can get it to run and idle but if I tip the saw forward it dies everytime.
It sometimes has an erratic idle and wants to rev on it's own with no bar and chain, and then sometimes doesn't want to idle well with the bar and chain on. I have probably consumed enough beer messing with this thing, I could have and almost wish I would have just bought a new one. Thanks and here is a pic hopefully to spark more interest. :hmm3grin2orange:

 

[tlandrum]

definately sounds like an air leak. i have a perfect running 460 and if i tip it upside down to unsnag it it will die too.

 

[Paul001]

Yes you can do a pressure/vac check, see my sig for details.

I would do the pressure/vac test, take the care back apart and find someone with a ultrasonic cleaner. Even if you have to pay them to run it through for 20 minutes or so, it's worth it. I use to run 7 or 10 on rebuilds, since switching over to mineral spirits and bumping my cleaning cycle up from 5 minutes to 15, I haven't failed on a rebuild yet.

The carb you have on this saw I've never known to develop an air leak around the shaft. So either you screwed up on your rebuild, still have gunk inside the carb, an air leak, leak in your fuel pick up, etc.

Start with the basics and one of those basics is the simple hand tools needed to do a pressure/vac test. Otherwise that "arm and leg" your dealer charges, aint that expensive if he has the tools and knowledge to fix it.

 

[pioneerguy600]

Time to have a vac test performed on it to rule out air leaks from some source, vac tests are a must when troubleshooting any saw that has erratic idle and revs up and down the scale.
Pioneerguy600

 

[willis09r]

Thanks guys! If i do have an air leak, does the case need split in order
to replace the seal/gasket or whatever is leaking? Or does that just depend
on where the air leak is? I don't think I'm ready for any case splitting yet.

 

[volks-man]

Thanks guys! If i do have an air leak, does the case need split in order
to replace the seal/gasket or whatever is leaking? Or does that just depend
on where the air leak is? I don't think I'm ready for any case splitting yet.

depends.

if the crank seals are shot you can do them without spitting.
if the case gasket is shot you will need to split the case or ...............
sell the saw.

 

[AdamL]

I'm betting the saw has a hole or tear in the intake boot, I had a 460 in the shop yesterday that would start and run sometimes only to idle erratic and die. When the saw was flipped or moved in a fasion that flexed the av buffers the hole would open and cause it to stall.

 

[AdamL]

ok just reread the first post already put a new boot on it... leak down test is in order to check everything else.

 

[pioneerguy600]

A vac test will also test the boot, and the connections between the carb and cylinder.
Pioneerguy600

 

[Jacob J.]

vacuum/pressure test the saw next to check for air leaks elsewhere. make positive your fuel and impulse lines are good and if all else checks out well, IF you can borrow a used carb or try one off another saw i'd check that, i've chased many "air leaks" before and only to find out my carb was junk. live and learn. I hope something turns out soon. remember, check and double check alllll the basics first. then we can move onto the major stuff.

Check which model of carb it is too. Some of those Walbro carbs have a nylon one-way check valve that can fail.

 

[cuznguido]

Well if you get tired of tinkering with it, I will trade you a really nice 310 for it, and take my chances.