Quick Tip #3 - Chainsaw Impulse Lines

[@artemusdee]

After a very discouraging encounter with the local Stihl dealer, who wanted $70 just to tell me what might be wrong with my saw, with repair estimate possibilities nearing half the price of a new saw. I took my saw home and started taking it apart myself. I found this cracked impulse hose on my 1996 024 Super, a fine little German chainsaw. The impulse hose and the carb kit were $35 and my little screamer runs like a champ. Thanks Dony.

[@andrewkeene6429]

Every time I watch one of your videos I learn more about the features of my older Stihl chainsaws. Using the impulse line tip and intake boot tip I fixed my 028 WB so that it now runs better than ever. Thanks again for all the attention you pay to these great saws.

[@jrp1346]

You even use proper English, grammar, and sentence structure. You are one class act!

[@TheLimbReaper]

No problem. I know you put a lot of time and effort into producing videos. They may not always pique my interest in every case, but they are always appreciated.

[@ml2trick]

Nice job on video.Nominated you today.I have been a Marine,Small Engine Mechanic for 30 years and you make nice videos.You help a lot of people out.

[@donyboy73]

thanks for watching, greetings from Canada

[@wrayjordan8315]

Great tip! Really not much of a decision once it’s torn down to replace questionable boots and lines! Your videos are always spot on!! Wray from Ohio

[@bigtexas7580]

This is very true regarding the impulse line. I have an fs90r and an fs130r. The fs90r purrs like a kitten and runs stronger than the fs130r, which obviously is supposed to have more power than the 90. I installed a new carb and fuel line kit on the 130, tried to adjust it and it runs ok but erratic. Turns out the impulse line was cracked and not providing the vacuum for the carb diaphragms to work like they're supposed to. Replaced that impulse line and now the 130r runs like the 90r. Awesome vid!

[@milltek2]

Hi DonyBoy73, Just nominated you. Yours have to be some of the very best instructional videos available anywhere. Keep up the good work!!

[@Coloredeggfarms]

Nominated! You have a great channel and are very organized and make it easy for us to search for our problems with our power equipment. Keep up the good work!

[@srkitheone]

I live in a village near Ledinci. I must admit that I learned a lot with your videos.

[@MowerMan]

Cheers Dony I got my echo blower working this week thanks to your videos. Many Thanks

[@dennisspottedwolf1019]

answered several questions Donny.....thanks ;)

[@SteveRobReviews]

Would it be possible to make a jig to attach to the front of carb to presure test the whole system if you do a lot of these. Nominated you for sure.

[@donyboy73]

hopefully it will help out in your future repairs

[@reddogroad1]

excellent video! I want to change the impulse line on my Stihl 026. Which parts should I take off so that I can gain access to the line? I would also like to check the carb boot while I am at it. Thanks for the videos, they give me the courage to do my own repairs.

[@donyboy73]

yes make small metal plates and a liner of rubber for the intake and exhaust

[@RealManSkills]

Thanks for the information! I have been doing more and more 2 stroke repairs and this all helps me know what to look for.

[@TimBarney]

Your videos are tops! I nominated you for youtube's "On the Rise" channels.

[@donyboy73]

thanks!

[@fdort3971]

Timothy Barney how do you nominate someone or agree with your vote please?

[@TimBarney]

F Dort youtube is no longer taking nominations.

[@aj9270]

just nominated you Dony ! I really enjoy your videos and have picked up quite a few tips too !

[@dejanira2]

Yo, you on the rise and nominated too!!! I enjoy your videos and have no problem nominating!

[@gcarson19]

Anyone who has saved even a few dollars following Don's advice should take the time to nominate him! I gladly did!

[@erdalcoban3367]

Thanks Dony. It is very helpful.

[@johnforsyth8414]

I have a stihl 025 which stopped running after the winter. Put fresh fuel in and won’t start. Cleaned out carb & still won’t start. Can get it to run for a few seconds with starting fluid. The original vent tube is full of fuel? Would that prevent starting? Also do you have a video showing how you disassembled that chainsaw to access the impulse line?

[@spelunkerd]

Oh, Dony. Sorry for a goofy question. What does the impulse hose do?

[@TheKrayusKorianis]

It runs on the vacuum pressure from under the piston to actuate the pump diaphragm on the carburetor. Piston goes up, pressure in the line gets sucked into the crankcase. Piston comes down, pressure builds in the impulse line.

[@LawnWolf]

I just sent a nomination for you for the On The Rise program. Hope you get it Dony.

[@donyboy73]

you should replace coils, points and condensers, gap points at .020 and use oem parts

[@donyboy73]

thanks Liam

[@vajake1]

Thank you. I looked up Jeremy Fountain. Good information, but I much prefer your channel! Please keep up the good work. Also nominated you.

[@donyboy73]

just a handful, they are good saws

[@TOMA21207]

Just sent nomination. Keep up good work. You're the best dony.

[@srkitheone]

Nice video. I follow your video clips from Serbia, they are very good.

[@Patrick4959]

love the knowledge Donyboy73 thanku for the heads up its a really important part to look after the Outdoor power equipment old or brand new to avoid problems down the road when using them in the middle of a task for example cutting the logs of wood safely and cutting the grass clearing leaves with the leaf blower and trimming hedges with the Hedge trimmer and clearing snow with the snow blower or what ever as the common problem but a different model or unit that :)

[@zyplex1]

Dony, just wondering if you could replace that impulse tube with a regular fuel line ? Which might be a little more flexible. Thx for the great info.

[@donyboy73]

thanks for your time

[@donyboy73]

i have seen many cracked impulse lines on those, worn out crank bearings and seals too

[@Southernshaker]

what is an impulse hose? great video, thanks for your time.

[@obscur156]

Wow thanks for that quick tip,that was exactly my problem on my Makita DCS340. Merci beaucoup Don,j'apprecie enormement ton travail et le partage que tu fais. Sharing is caring .Thanks budy. Best regards.

[@donyboy73]

thanks richard

[@donyboy73]

thanks James

[@donyboy73]

yesn a leak down test, jeremyfountain may have a vid on it

[@donyboy73]

thanks Bob!

[@timthetoolman4575]

My vote is in. REALLY enjoy your videos. Do you have one on the Lawn Boy/Toro "personal pace" system and how it works? I have one I will be tearing into in the spring. It seems like the drive fails to dis-engage even when engine is not running? I have not torn into one yet as mine is brand new, but I bought a used one as a project. Too good of deal to pass up.

[@donyboy73]

thanks Patrick

[@donyboy73]

make sure your fuel/oil mixture is right

[@howseleslie]

Thanks Dony. Was hoping to see you take it down, so we could see how far we have to tear the saw down to get to it. looks like both top covers, air filter, handle, carburetor, and we can get too it.

[@johnclarke6647]

Loss of impulse pulse in a two cycle can be a intriguing problem. I have a used Stihl HS 45 that I picked up last week that has a similar problem. Normally I would just replace the impulse hose in normal routine maintenance if the saw indicated it was loosing fuel flow but the HS 45 has a stand-off isolation block used as a channel for the impulse pulse. My carb and fuel lines are pluperfect, so it is not them. I have two Zama C1Q carbs and I have swapped them out with the same results. It has to be the isolation block. I will check it out, today. Your thoughts? The hedge trimmer will run but only for a second or two, based upon how much I primed it.

[@trmdito]

Hi! Am writing regarding my father's mower. A TroyBilt w/ a Kohler 19hp engine. It will NOT start. Tried starter fluid, did not work, gas filter ok. Engine turns. I am thinking it would be either the key or the connection to the carb. Any Suggestions will be appreciated. Keep up the good work, love watching your channel. There is something new to learn. Gilberto

[@donyboy73]

thank you

[@trmdito]

Don: I want to know how to remove the screen from the fan on that Kohler I wrote you about. I was not able to figure it out and was not able to check for the key on the shaft. Please advise. My father wants to buy a new mower and am telling him not do. BTW he is 93 this month. I already sent you the information on the Kohler. Thanks Don and keep up with your videos, they are very informative. Gilberto

[@trmdito]

At my request for help you answered if the spark had "spark" yes it does. I put a new one, cleaned the carburetor and it did not work. Made sure it had compression, also confirmed the relay under the bowl works. The motor is a Kohler, s/n 3603332093, spec sv590-0017 Courage. Please advise, and thanks for your help

[@bismarckcro]

Hay donyboy nice video, but can you explain purpose of impulse line and how its work?? Can not find any vid. on youtube about that. THX

[@greasyHands66]

The purpose of the line is to transfer the vacuum created by the piston to the carburetor in order to suck fuel to the carburetor.

[@MrUbiquitousTech]

Thank you Jose, that's good to know.

[@AJlostinthewoods_]

Love the info buddy, respect your knowledge

[@gregcbn5795]

Is there a vidio to show how to get off the impulse hose (the end that goes into the cylinder). I can see it in there but no clue as to how to get back in there to disconnect. It appears even too tight for needle nose pliers and I have disassembled much of the saw but can't seem to seperate the trigger/handle from the cylinder to get back in there.

[@havenmeesteryakan2015]

Same problem here ! on a 024stihl How do i thake the damm thing apart and visa versa

[@EarlMantis]

Great Video Dony. I have the same exact chainsaw and had the carb kit replaced. It ran fine for a little while but now when I start it it seems to idle fine and then when I give it some throttle it dies out. Could this be the problem? I can send you a video later if it will help. It was my grandfathers chainsaw from the 1980's and i'd really like to get it running perfect again.

[@EarlMantis]

Thanks Donny I will send the video as soon as possible

[@JIMO415]

Hi there Dony, great videos! I came across your channel after getting a good deal on 3 saws, an 011AV, 024AV and an 036. I have gone in and done lots of needed cleaning and inspection on each unit. The 024 had a running issue I tracked down to a bad impulse hose just as you have here (fast idle that could not be turned down and intermittent idling, falling flat on revs). The pressure/vacuum testing vid was helpful on that! The 011 is good to go. Question on the 036 though: The clutch was run hot and cooked the bearing and it ate crankshaft. I assume that needs to all be replaced. I see after market kits out there. I worry about quality. Are there brands to consider safe or do you know of any to stay away from. I paid up buying Sthil branded hoses for the 024 repair. Was that necessary? Are there good sources you can recommend to buy decent quality parts (OEM or aftermarket) from so I can thoroughly restore the 036? Crank kit, gaskets, hoses ect... Thanks!! Jim

[@donyboy73]

not yet, thanks

[@donyboy73]

Thanks!

[@donyboy73]

thanks

[@donyboy73]

thanks Randi!

[@donyboy73]

thank you sir

[@donyboy73]

yes

[@donyboy73]

thanks!

[@donyboy73]

it sends impulses of air to the carb to make itable to pump fuel

[@havenmeesteryakan2015]

Hai Dony thanks to Your vid I just repaired my 024 , the impuls line had come of on the engine side,I have thinkert a lot on other brand,s whom all had the carb direct on the cilinder with no impuls line like this Thanks Man!

[@splash5974]

Do you remember what your symptoms were? I just picked up an 024 and its starts up fine, but as soon as you try and make a cut with it, it just runs out of power and dies...

[@oldtree13]

fantastic videos, pl show taking off main handle housing bolts

[@JOEZEP54]

I have a craftsman 16” 36cc ---06118D20933. It starts up ok but bogs down when I start to cut. If I hold it tip pointed up & cut that way it runs fine. After cutting for a few minutes I can cut holding it level. But it will start to bog down again. It is not leaking any gas. Does this unit have an impulse line? Thank you

[@warriordriver350]

Whats an impulse hose ive never knew what those are / what they do??

[@donyboy73]

greetings from canada

[@jakesnake_27]

Great video, stihls are definitely the best!

[@HaraldFranzen]

Nomination done and thanks Don for your work and sharing it!

[@donyboy73]

sends impulses of air to the carb to make it pump fuel

[@donyboy73]

it sends impulses of air to the carb so it can pump fuel properly

[@geronimopascuale9208]

great video but next time show how you took it apart and put it back again . Thanks you

[@donyboy73]

sometimes it works yes

[@monsterkhaos9292]

Hey I got a quick question I got a McCullough. Mac 4600 chainsaw and I've noticed I've had to switch all the fuel lines especially the pulse line but the one problem I'm having is how can I get down in there behind the case and the motor to plug the pulse line in there's no way you can get down in there you got a video on how to change that on that saw

[@donyboy73]

I will very soon

[@VintageOutboardMan]

very good tips dony! keep making these fantastic videos man!

[@donyboy73]

thanks man

[@donyboy73]

first check for spark

[@donyboy73]

thank you!

[@pennypingu]

How come you make such awesome videos dude

[@AD4203]

Have you ever delt with any shindaiwa chain saws?

[@fototropism]

wow! simple video, simple problem. thank you for sharing your knowledge with us. very helpful brother

[@donyboy73]

thank you sir!

[@markshiflett7966]

Do you think it is good practice to change all fuel lines when you do carb kits?

[@TheHeadlessHorseman]

Just sent a nomination. Thanks for the videos

[@greendts]

Voted and praised you and your channel

[@billkrause4585]

I like these TIPS ... Thumbs Up!

[@tedkapanjie6038]

Donny Boy, my Stihl 025AV had symptoms of a leaking impulse line,, hard to get the carb adjusted and it dies if the saw is inverted, I replaced it impulse line and have not yet tested it as I don't want to anger my neighbors on Thanksgiving. I have examined the old line and intake boot. Nothing obvious in the way tears. I I replaced both. I did pressure and vaccum test the impulse line and it does not hold pressure or vacuum after 7 minutes. I think there is a very small leak not like what you showed in the video. Is a small leak enough to cause issues?

[@Datsun280zeeee]

Hey Don, when do you think you will upload that video of the Artic Cat Kitty Kat?

[@thanxx]

Thanks for all your videos mate. you truly are the Oracle of all things STIHL :)

[@donyboy73]

thanks for watching!

[@thanxx]

donyboy73 No worries. within the space of four days ive fixed my 028,my ts400 and rebuilt the carb on my fs410 all thanks to your vids.

[@vajake1]

How do you check for an air leak through the crank shaft bearings? Some sort of leak down test?

[@alestevane8456]

donyboy great videos do you happen to have the size of the spindle for stihl 060 iam traying to fabricate the spindle with out the crank shaft

[@Deadbuck73]

I'll vote for you any day! But it's hard to vote for you as being on the rise when you're already tops!

[@johnclarke6647]

When I rebuilt my Stihl 029 for the third time I put a new impulse line on it. Later I had to replace the coil because it was bad. It ran great for a week or so, even after I replaced the coil but all of a sudden it would not idle. It cranked and ran great at high speed but at idle - it died. I could think of all kinds of possibilities, seals, carb and other things that could cause it not to idle but I felt it had to be something simple. . I started wondering if it was the impulse line? Did it get partially unplugged when I put the new coil on it? Yes, it had about 3/16 of an inch, so I push it back on the fitting and put the saw back together. It ran and idled like a champ, so that was the problem. I decided if it gives me anymore problem I will remove it , clean it with break cleaner and put it back on with 1184. If able I will also put a small cable tie on it to make sure it stays on the fitting.

[@donyboy73]

thanks man!

[@Thebowzer221]

Dony, I 2 have an 024 saw. Hard starting son of ah gun. Always has been. Had it serviced 1 time and wz no different (they said they installed a carb kit, cost $62.00 American). Starting either gets it going everytime. Good saw, I have had it over 20 years. Just a bear 2 start, unless U have starting either. Bowzer.

[@noellwilson1273]

Good info but - I watched your videos on the STIHL 017 clutch & oil pump area and ordered a double handful of aftermarket parts and spares. Still no chain oil. Yesterday I ordered an oil pump. Today I wish I had considered an impulse hose and intake boot even though they aren’t connected to the chain oil system. How about a list of likely soft parts and parts that are likely to need replacing? For those of us willing to try aftermarket parts, the cost for extra parts is not much compared to multiple part orders.