Difficulty starting (almost new) 661

[Backstage]

Thank you Ernie. All our saws have only seen cans of pre-mix. We have been fortunate to have gallons of Tru fuel and similar donated. We don’t allow any of our saws to be fueled w “gas station”mix. Too many volunteers may mix incorrectly. After Hurricane Michael we had two pallets donated of a Jonsered 2-Cycle 50:1 Pre-Mixed Fuel otherwise we buy Tru Fuel or it is donated.

I have had that TruFuel brand stuff go bad on me. Also, if you're dealing with volunteers, God bless them, they sometimes get "better ideas". Look first unto thy fuel, and lo, thou shalt be blessed.

 

[sawfan123]

The first thing that should be taken apart is the muffler.

 

[cookies]

step 1 pull muffler and inspect for scoring, if clean proceed to step 2
step 2 remove carb, remove fuel cap and try to blow through fuel hose to check filter ..it should flow air easily
step 3 clean carb of varnish

 

[Husky77]

I would not use carb spray on it, unless it was apart, and the fresh fuel mix did not dissolve the dried up fuel mix, (if that is indeed your problem).

Try fuel down its throat/ plug hole, that does 2 things, proves you have spark, as it will run for a bit, and also may pull enough vac on the fuel pump due to the pulse of higher rpm (way higher than hand cranking with the pull cord), and may free the needle, and flow fuel.

Try that first, its good advice from IRHunter, then get back to us and we can methodically step thru it so you dont leap frog over the problem.

Stick to a plan, dont get distracted, and try too many things at once, you will leap frog over the issue, only stupid question is the one you dont ask.

I have found a metering needle stuck a few times on different saws that been stored a long time (not used frequently) almost always I take carb filter off and add some fuel into the carb, same as down the plug hole but works better for me. I only use Aspen and it seems to happen with this as well as pump fuel. Strangely it never used to happen pre unleaded years ago so could it be something to do with the oil used back then? Or maybe I'm looking back with rose tinted glasses!

 

[Stihl Learning]

Carb solenoid.

 

[SteveSr]

Spending more time on this site i now understand CAD.
We have a MS661 that’s about 2 YO. Prolly run 3-5 tanks. Most recently run at Newnan GA tornado response last year. Recently went to help remove a 42 in poplar and it never popped. Checked plug and was dry. Certainly welcome thoughts on diagnostics or starting options. Obviously I’m not a saw mechanic. Pulling the cord on that saw a continuous 25-30 times at 66 is a bit different than at 56 … even w compression release. TIA

Is this saw M-Tronic or carbureted? Put up a pic of the silver engine family label on the handle. M-tronic adds a few more possibilities.

If the plug is dry after all of that pulling you need to remove the air filter and make sure that the choke is fully closed when trying to start it.

You should be able to store it over the winter with canned fuel in it. Any possibility that someone put regular pump gas in it?

 

[Howard Justice]

Is this saw M-Tronic or carbureted? Put up a pic of the silver engine family label on the handle. M-tronic adds a few more possibilities.

If the plug is dry after all of that pulling you need to remove the air filter and make sure that the choke is fully closed when trying to start it.

You should be able to store it over the winter with canned fuel in it. Any possibility that someone put regular pump gas in it?

SteveSr, Thank you for your response. Not M Tronic and all of our saws use TruFuel or similar. And this one always stays with me. Great point about the choke… I will check that out as well. Again thank you!

 

[Howard Justice]

Let us know what you find, rekon the stuck needle is the best place to start, dont be tempted to remove the fuel filter and blow back thru the fuel hose to try and unseat it, most likely will pop off a fuel line.

So get back to us, did putting some fuel down its throat, or in via the plug make it try to run, but then die off as the fuel was consumed ?

Edited to add,

take off the air filter cover and have a good look at the wiring etc, make sure no critter has been in there eating/ nibbling and causing any obvious damage too the fuel solenoid side of things.

Ummmm, that is an excellent point! It is actually kept at a place …. An exterior garage where such an unfortunate event might happen… Haven’t thought of that before… Usually think about that w vehicle sitting for a long time in a garage or outdoors and a mouse eats wiring… I guess they have no aversion to chainsaw wiring as well? Outstanding suggestion.

 

[Howard Justice]

step 1 pull muffler and inspect for scoring, if clean proceed to step 2
step 2 remove carb, remove fuel cap and try to blow through fuel hose to check filter ..it should flow air easily
step 3 clean carb of varnish

Thank you.

 

[CatMan Fetters]

Replace fuel filter, replace spark plug see what happens.

 

[SteveSr]

SteveSr, Thank you for your response. Not M Tronic and all of our saws use TruFuel or similar. And this one always stays with me. Great point about the choke… I will check that out as well. Again thank you!

Have you verified spark? You may need a dark room to see it. Best to use a second plug with a wider gap.

Other than that try squirting some mix down the carb throat and see if you can get it to fire. This may breakup the cob webs in the fuel system... but canned fuel isn't supposed to cause these???

BTW, I have left non-E pump gas fueled saws that have been drained and run dry in storage for up to a DECADE and they have always started right up when needed with fresh fuel. Never had a needle stick.

 

[angelo c]

Where did you find a non mtronic 661 ? Not many here in US

 

[r black]

Take it back and replace it with a Husqvarna 390xp, and cut wood ...........

 

[trains]

Ive seen needles stick before, lets keep it simple for now, need to find what the problem is, not just throw parts at it and hope for the best.
Its been mentioned to put some fuel in it to see if it fires up, and it may even unstick the needle, and then run from there.
yes taking muffler off to inspect is worth while, but there was no indication that there was issues when it was last running, but yes, a good suggestion.

Lets go one step at a time and find the issue, so he dosent burn up the saw.
I missed the bit where he mentioned it was not an M tronic saw in the OP, so assumed it was.

Lets see what response we get to some fuel in it, and what the piston is like, and go from there.

 

[thenne1713]

With a dry plug, sometime very early in the diagnose phase, I pour a bit of mixed gas down the plug hole (say, 1/4 teaspoon), reinstall plug and boot, try to start.

If pulling plug on a NO START, stick compression gage in it and get a reading to rule out stuck ring; had one stick on me, after end of day of day-2 on new saw, but did not know for 2+ yrs later (when out of warranty), due to medical.

 

[Howard Justice]

Have you verified spark? You may need a dark room to see it. Best to use a second plug with a wider gap.

Other than that try squirting some mix down the carb throat and see if you can get it to fire. This may breakup the cob webs in the fuel system... but canned fuel isn't supposed to cause these???

BTW, I have left non-E pump gas fueled saws that have been drained and run dry in storage for up to a DECADE and they have always started right up when needed with fresh fuel. Never had a needle stick.

Thank you!

 

[Howard Justice]

If pulling plug on a NO START, stick compression gage in it and get a reading to rule out stuck ring; had one stick on me, after end of day of day-2 on new saw, but did not know for 2+ yrs later (when out of warranty), due to medical.

Thank you for your insight!

 

[Howard Justice]

Replace fuel filter, replace spark plug see what happens.

Thank you Catman!

 

[Howard Justice]

Where did you find a non mtronic 661 ? Not many here in US

Georgia

 

[Howard Justice]

Have you verified spark? You may need a dark room to see it. Best to use a second plug with a wider gap.

Other than that try squirting some mix down the carb throat and see if you can get it to fire. This may breakup the cob webs in the fuel system... but canned fuel isn't supposed to cause these???

BTW, I have left non-E pump gas fueled saws that have been drained and run dry in storage for up to a DECADE and they have always started right up when needed with fresh fuel. Never had a needle stick.

Yep! Sold on TruFue! Not cheap but in disaster response environment absolutely necessary. We are extremely fortunate to have most of our fuel donated. Thanks for your comments!!