Husqvarna 141 impulse pipe

[mutt07]

Hiya all, hope everyone is healthy and safe during these crazy times. Hey guys, question about the Husqvarna 141 impulse pipe. It appears the carb gasket to the plate blocks the impulse tube. Now maybe I'm crazy Nd don't fully understand the impulse idea fully, but how can it apply vacuum to pump fuel from carb to combustion camber if the carbs factory gasket is blocking it? The entire carb was rebuilt, properly setup with walbro tool for metering lever. New everything TWICE. Even bought an after market carb and still no start. Few pops back through intake but no run no chug no stall. No start period. Wt 660 original walbro carb. New plug. New coil new flywheel. Filter new everything new. Carb screws L AND H turned out 1 turn according to specs. No go. Turned 1/12 nothin. 2 turns zip. Compression 140psi. Bright blue spark. Plug not wet almost As if no fuel is making it from carb. Impulse keeps coming up. Replaced it. Twice. Nothin. Seems to me with the port blocked by original factory carb gasket it ain't gonna start. Please educate me that I'm wrong. Have a blessed day all

Mark

 

[Totembear]

Pics?

 

[mutt07]

Pics?

Of the saw Totembear?

 

[cscltd]

i think looking for pics of were you say gasket blocks the impulse pipe- may not be the right gasket?

 

[mutt07]

i think looking for pics of were you say gasket blocks the impulse pipe- may not be the right gasket?

Oh gotcha. Well. The gasket is the factory one, never replaced in fact in good shape. The impulse pipe WAS split and I replaced on advice given here. I'm just looking at it and stumped how if the impulse deadheads against the gasket it just stumps me. I got all three: great spark. Great compression zero scoring on cylinder wall, and fuel....I thought. If I richen it by slightly raising metering lever then yes the plug wets. If I adjust it according to the WT on walbro tool, then no more plug wetting but now am I getting enough fuel. It appears to be misting as it should, but who really knows,cause there's zero start. First time in my life I have failed to geta gas fired engine to fire. Not all ran well until problems were ironed out but never not fired. This is truly the first in my 58 years. Well. 50 I started working on engines at 8. I'm pretty upset by this of course lol

 

[mutt07]

Of the saw Totembear?

 

[mutt07]

i think looking for pics of were you say gasket blocks the impulse pipe- may not be the right gasket?

 

[Chevboy0167]

Did the new flywheel have a key cast into the taper? I ran into a saw that had no key cast into the taper from the factory. After I installed a new piston and rings, put original FW on where I thought it should be, I tightened down the FW with 1/4" impact. Put rest of saw together. Went to start, fired over but chain spun backwards. Yes... a 2 stroke can run in reverse in certain conditions.

Knew what happened right away. Pulled FW back off to find out FW never had the key cast into it like it should have from factory. My impact spun the FW out of time. Right on the face of FW just above the area where the washer and nut sits but below the fins, should be a dot or small line sticking up. That should line up where the key is or should be cast into FW. Line that mark up with slot cut into the crankshaft, press FW down on taper, install washer and nut finger tight, finish tightening up with socket and ratchet hand tools.

I use some extra starter rope down the plug hole as a piston stop. Please look this procedure up on YouTube for the correct way to do it or you can wreck the piston ring or worse. Or get a plastic piston stop made for saws.

I set coil gap with a business card. 8-10 thousands I think??? as the FW magnet pulls the coil tight against it. Tighten down coil bolts and spin FW as you pull the card out.

Install recoil and check for spark with a new plug laying on top of cylinder. Spark must be strong. Bright blue, 1/16" wide or so and consistent as you pull it over.

 

[cscltd]

Item #3 the plastic adapter has a channel moulded in from pipe area to the small hole in the bottom of gasket I believe that allows the crankcase charge to reach carb.
try squirting a little mix down carb throat and see if it starts. U may have an air leak, also take off the metal clip that holds plug wire to cylinder if still there-they give problems.

 

[mutt07]

Did the new flywheel have a key cast into the taper? I ran into a saw that had no key cast into the taper from the factory. After I installed a new piston and rings, put original FW on where I thought it should be, I tightened down the FW with 1/4" impact. Put rest of saw together. Went to start, fired over but chain spun backwards. Yes... a 2 stroke can run in reverse in certain conditions.

Knew what happened right away. Pulled FW back off to find out FW never had the key cast into it like it should have from factory. My impact spun the FW out of time. Right on the face of FW just above the area where the washer and nut sits but below the fins, should be a dot or small line sticking up. That should line up where the key is or should be cast into FW. Line that mark up with slot cut into the crankshaft, press FW down on taper, install washer and nut finger tight, finish tightening up with socket and ratchet hand tools.

I use some extra starter rope down the plug hole as a piston stop. Please look this procedure up on YouTube for the correct way to do it or you can wreck the piston ring or worse. Or get a plastic piston stop made for saws.

I set coil gap with a business card. 8-10 thousands I think??? as the FW magnet pulls the coil tight against it. Tighten down coil bolts and spin FW as you pull the card out.

Install recoil and check for spark with a new plug laying on top of cylinder. Spark must be strong. Bright blue, 1/16" wide or so and consistent as you pull it over.

Yeah the fw key is in great shape. It's timed , bright blue spark etc. It's almost as if it's NOT getting fuel. Friday I had the Piston out. Ring is secure and in good shape Piston looks fine, little carbon but nothing to cause no start. I mean not even a chug. I'm tryna figure out how to test the carb to make sure its actually misting fuel thru to the comb chamber. It's easy to check for too much fuel by lifting the metering lever too high but when the metering lever is set to the tool and supposedly correct it's not so easy to check except if it starts which it's not. Any ideas there??

 

[Chevboy0167]

Well that escalated quickly.... Did you try some mix fuel down the carb throat to get it to pop over?

And yes, the gasket between the carb and bulkhead must be positioned correctly. Most gaskets come with a hole in them on top and bottom so kinda hard to screw that up. Holes in gasket and carb must line up and seal to provide vacuum from crankcase to operate the fuel pump circuit in the carb.

I have seen worn crank seals leak on a vacuum test and cause poor or no pumping of fuel.

 

[mutt07]

Well that escalated quickly.... Did you try some mix fuel down the carb throat to get it to pop over?

And yes, the gasket between the carb and bulkhead must be positioned correctly. Most gaskets come with a hole in them on top and bottom so kinda hard to screw that up. Holes in gasket and carb must line up and seal to provide vacuum from crankcase to operate the fuel pump circuit in the carb.

I have seen worn crank seals leak on a vacuum test and cause poor or no pumping of fuel.

Yeah. I tore her down to barebones and rtv'd her back together to make sure she's sealed. Ring looks great.

 

[mutt07]

Well that escalated quickly.... Did you try some mix fuel down the carb throat to get it to pop over?

And yes, the gasket between the carb and bulkhead must be positioned correctly. Most gaskets come with a hole in them on top and bottom so kinda hard to screw that up. Holes in gasket and carb must line up and seal to provide vacuum from crankcase to operate the fuel pump circuit in the carb.

I have seen worn crank seals leak on a vacuum test and cause poor or no pumping of fuel.

Chevy, I even made a new gasket to be sure. Yeah. My eyes from being sick are sketchy lately but I see the impulse holes in the gasket. Impossible to goof that up lol

 

[Chevboy0167]

OK, did you pull off the FW side bearing/seal and check to see if it was worn or hardened? Sometimes a visual and pliable finger test can lead you to a problem.

 

[HarleyT]

Sometimes a visual and pliable finger test can lead you to a problem.

It always gets me into trouble...

 

[Backstage]

Not popping when you manually add a bit of fuel…so it’s either spark or air.

No wet on the plug when you crank it…so it’s not taking fuel in. Sounds like it’s not getting air drawn past the carb jets? Starts with filter removed?

 

[cookies]

pull the flywheel, check the key...it sounds like ignition is out of time

 

[mutt07]

pull the flywheel, check the key...it sounds like ignition is out of time

flywheel key is brand-new , albeit aftermarket fw. The plug no longer is getting wet, when previously it was always wet, until I adjusted metering lever, used walbro tool. But... Started at 1 turn out each as manufacture recommends on L & H jet screws. Nada. So, being Ocd that I am, I began at 1 turn, then incremented all the way up too 3 pulling in between , choke and no choke. No flooding anymore but also nothing on plug. At this point I then took out L jet and it was wet.....hmmm I thought, it's wet but not passing fuel on. Impulse tube. Kinda dampish, so it's making it to the gssket. Some fuel at carb rubber boots, but still no fire up. It SEEMS as if all three are present,spark, fuel, air but one has to be weak or missing. Has to be. It doesn't even chug. Not once. Well one pop back thru intake stopped me thinking, RICH?, then nothing so I moved on. Seals on both shafts seem integral. Big word for me lol. So,good fw key, seals ok, I still feel she's starving. So I installed the cheapo carb I got with the new coil.
seeing yes it gives a bright strong spark outside of cylinder but means nothing unless it Sparks inside the same, could the new carb, not a walbro or Zama be punky too? Maybe..or is it just the unit reached its age...mmmm not to me. If u can rebuild model t's then the answer is no but I...me, personally cannot figure this one out. You guys have given mad awesome advice, of which I've tried, multiple times, which leads me to the weird part.....multiple times

 

[Chevboy0167]

Hang on mutt... let me go tear down a 141 quick to see where the FW sits. Maybe your "aftermarket" FW magnet is placed on the FW incorrectly.

And yes, the aftermarket carb may be a dud also. I find they can be hit and miss for a good 1.

Give me a yes or no to this. Will saw pop over like it should with fuel straight down carb throat? Or even pull plug and drop fuel in, replace plug and pop over???

 

[cookies]

get a compression reading, flywheel magnets do go bad. mark the flywheel and case at top dead center so the marks line up. use a timing light to check ignition timing. if you squirt fuel mix into the carb throat and get 0 run time or attempts to run you have problems in the ignition system or compression problems.