FIXED - Why A 2 Cycle Leaf Blower Engine Idles But Won't REV-UP! MUST WATCH!

Why A 2 Cycle Leaf Blower Engine Idles But Won't REV-UP! MUST WATCH!
In this STEP BY STEP video I show you how to easily repair a 2 cycle Sthl leaf blower that won't idle properly and rev-up.
Crank seal is part number 9639 003 1230
Don’t forget to click the 🔔 to turn on Video Notifications for more money saving videos and tips, featuring all the brands like Stihl, Husky, Husqvarna, Honda, Echo, Tecumseh, Dolmar, Makita, Poulan, Ariens, Briggs and Stratton, Murray, John Deere, Craftsman, MTD, AYP, etc.
Help me make videos or buy me a beer!!
/ donyboy73
Connect with me on these social media spaces (plus that's where I announce contest winners)
Facebook: / donyboy73-th. .
Twitter: / donyboy73
Instagram: / donyboy73
If you enjoy my videos make sure to comment, share, thumbs up and subscribe. Thanks for watching!
Easy to follow and thorough step by step tutorials do it yourself (DIY) to help you with your broken lawn and garden equipment including snowblowers.
I do my best to teach you how to easily diagnose problems the fastest, quickest and most efficient way with real repairs beyond just replacing a spark plug. These tips are for both the homeowner and shop owner.
Whether it be a handheld, two stroke, two cycle engine like a chainsaw, weed eater, weed wacker, string trimmer, grass trimmer, line trimmer, hedge trimmer, strimmer, brush cutter, leaf blower, or four stroke, four cycle units like a lawnmower, wood splitter, lawn tractor, snowblower, pressure washer, generator or a ride on mower that needs parts installed or replaced, I’m your go-to guy.
My favorite brands of spark plugs are NGK and Champion and are the ones I recommend.
I’ve been a small engine mechanic for many decades and also run my own repair shop so my videos are loaded with tips and tricks that I have learned and want to share with you. You will also find many tool and product reviews from top brands on my channel as well.
I have the largest Small Engine Repair Video Library on KZbin and the entire internet with over 1200 videos, just GOOGLE "DONYBOY73"!
#donyboy73 #db73 #smallenginerepair #howto
I want "DON THE SMALL ENGINE DOCTOR" on KZbin to save you time, frustration and most importantly, MONEY with my HOW-TO videos!
Due to factors beyond the control of DONYBOY73 “The Small Engine Doctor”, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. DONYBOY73 “The Small Engine Doctor” assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. DONYBOY73 “The Small Engine Doctor” recommends safe practices when working with power tools, hand tools, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of DONYBOY73 “The Small Engine Doctor”, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not DONYBOY73 “The Small Engine Doctor".

[@p71collector]

New sign outside of Don's shop. "I don't repair space shuttles" LOL!

[@mada658]

🤣🤣🤣😔😔

[@PAToph]

He probably would and could...

[@charlesrose7212]

Ha!

[@Cliffhanger365]

Something to be said about a small engine mechanic teaching the world how to fix their small engines. You are the MAN

[@michaelspencer301]

You hit the nail right on top of the head ! You put more time in fixing that unit than it's worth. I've done it many times just to fix it and cut the customer a good deal . I know why you did it to show everyone how to. 75 % of the blowers I work on aren't worth fixing . And they are ahead to just buy new. Great video!! 👍

[@shaverdave3644]

That would make a lot of neighbors happy

[@jim21804]

Great video. I would have never figured that out myself. I agree it would cost more to fix at a shop than its worth. That is why I love your videos. My push mower was built in 1964 and the old Briggs still starts on the first pull.

[@matthewwearsch242]

Hell yeah 👍 I love those little handheld Stihl blowers especially the older ones without the EZ start recoils I've had my BG 55 for over 20 years

[@paulwharton1850]

What would we all do without you Dony ? ! Not much, that's for sure ! Thanks so much for this video - most helpful.

[@gardenfork]

I learned something today! Eric.

[@waynetetley584]

Great explanation. Never stop learning. Thank you

[@THEMOWERMEDIC1]

Great fix ! I had to do the same repairs to a STIHL br420 Magnum. Notorious for oil leaks! Have a great weekend Don!

[@donyboy73]

take care jeremy

[@BrucesShop]

Thanks Don. So many folks don't understand this. Crank-seals.

[@acreguy3156]

Thanks, Don!! Mine is doing the exact same thing - bogging down. When hot, it will rev up to full speed and then drop back to about 75% after a few seconds. I'll look for that oil leak.

[@sailme2day]

wow Don, looking with an eyes , nice detective work to prevent throwing parts at the problem . Vacuum leaks can be a headache. thanks for the lesson :)

[@fegolem]

Had similar behavior with a leaf blower. Tank vent on cap was clogged. Engine/carb pulled a vacuum on tank and wouldn't let enough fuel flow to run beyond idle.

[@alext8828]

Mine had a dirty mesh filter. The only thing I didn't replace the first time. It's not running perfectly, but it's running.

[@KB-ic3th]

Thank God that leaf blower is fixed. After the homeowner gets all the snow out of the way, they can get back to blowing leaves.

[@sonic5d]

This was the definitive answer I was searching for days trying to figure out why my 2-stroke engine refused to stay in a revved position and why every other day, the idling would change drastically. Thank you very much!

[@Kushert]

Your a true professional. Wish I found your channel sooner.

[@kevinwoodcock7578]

More great tips from the best small engine doc on the youtube. Thx Don.

[@barryestell6324]

You are very good ,,and I watched a lot of repair guys ,,got to give you 10 stars ,,very good .

[@paulmorrey733]

Thanks Don

[@Jim-ie6uf]

Man that made all the difference. Only ran across that once on a 2 cycle LawnBoy mower.

[@crazycanadian7741]

Hi Don, had the same problem with my air blower, BG56 but mine had no gasket liking, had left it aside for 6 months, and when I needed to use I only turned the 2 screws and it's been running perfectly, thanks for all your useful information from Samos Greece, at the end of the world, formally the taverna at the end of the world, p.s will keep looking at your videos, Andreas.

[@mikejones6974]

Sounds good 2 me. I got hung up on a chainsaw one time with leaking seals. Got it running but went in several wrong directions first! Great vid!

[@ajemt3345]

This is EXACTLY what mine is doing. So glad I found this video. Well done and easy to understand. Thank you,

[@InTheDogHouse3DPrinting]

Anytime I work on these or any 2 stroke motor that I have to replace the crank seal, I always check the crank bearings. But the first thing I do is perform a compression test to see if they are worth fixing. One thing that a lot of people do is to put in an aftermarket spark plug, and they will run like crap. Always make sure it has the proper spark plug in it. Some use a resistor plug, some don't. I never use a screw to punch a hole in the seal, I use a small punch to make a hole, then use a seal puller, or pick like what you used. And I always check the flywheel key to make sure it's not messed up. I always adjust the carb after any repairs to make sure it's running well. I have found out the factory settings are rarely ever correct because most of them are set at sea level and don't work at higher elevations. There are so many variables on these to check you need to have a good ear, and a lot of experience so you know what to look for so you aren't spending so much time troubleshooting them.

[@1funcar]

Wish I would have known this a few years ago. My blower had the same symptoms and the local shop couldn’t figure it out, so I gave it away and bought a new one.

[@tonylozano2742]

Great video my Stihl blower has the exact same symptoms.

[@Johadart]

Thanks , fixed my exact problem with my Stihl blower. Same one.. 🤙🏼 keep up the great work bud 🤙🏼🤙🏼🤙🏼

[@donyboy73]

Great to hear!

[@JSchrumm]

Thanks Don I have a BG85 that I put a new carb on with no positive result I will check that seal for a leak great info.

[@pootthatbak2578]

Like he said..not always the crankshaft seal..my bg65 now apart. Front of engine, closest to muffler is soaked, seal dry. Suspect now, that lower housing gasket blown..not really a sump, but the lower half of engine. 4 bolts below the crankshaft seal. Theres a red gasket or sealant.

[@craigsmith9876]

Thanks got the same problem on my stihl FS90R Ive noticed an oil leak on the crank case. wasnt sure whether it was fuel or ignition but after watching your video i am pretty sure its the same problem with the seal. Thanks for posting.

[@user-kp6js7vp5h]

Very informative as usual. Love your videos.

[@motoman5023]

Excellent video Donnie that has happened so many times at work you put a carburetor kit and it doesn't fix it then you're searching for another problem like you said they're not worth putting too much money in this kind of thing drives my boss crazy we waste time and effort starting with the kit then we have to go to something else now you've exceeded the price of the blower these things can drive you crazy great video

[@donyboy73]

absolutely

[@Mopar-Pioneer]

Thank you Don. What you have just shown is vital info for home handymen who can't afford to throw something out and get a new one. would like to know if you have done a vid on how to do a leakdown test on a 2 stroke motor. Thanks mate. Oh yeah, that blower from Stihl here in Australia would cost around $ 250 to $ 300 Australian ! Alex, expatriot Canuck

[@louiel8711]

Good one Don, 2 strokes can be a nightmare. I stopped working on them myself, no money for me after the repair.

[@paulk3681]

An excellent, clearly presented video, thank you

[@jacquescote2585]

Ha...ha ...! as an aircraft tech I was wondering if you would apply a torque value on the flywheel, but the answer came before I finished my questionning!

[@josedejesus6185]

Excellent instructional video, Danny! Keep up the good work!

[@inhocsigno9151]

I had the exact same list of symptoms on my Ryobi BC30 brush cutter/string trimmer. It blew out the cyl to crankcase gasket. The cyl mounted with only 3 screws vs 4. The new gasket had embedded line of sealant all around it. Now works great again.

[@billlovett4256]

Great as always, I was looking for a big pick like you used. I found it, it's called a Cotter pin puller and it also works really well for pulling out Cotter pins! I love it. Keep it up.

[@DS-kn4bs]

Lol

[@flhusa1]

yep those cotter pin tools are handy and come in at least two sizes maybe more.

[@wayneberry8703]

Great job, Dony....

[@rjpropertymanagement5163]

Thanks Dony have been following you for alot of years excellent videos always enjoy your knowledge and the way you explain everything thanks your friend Rocco from CT 😉🤙💵💲💵

[@225rip]

Great job

[@christopherreddy5270]

This is an excellent video. I've got the dreaded oil leak and thought it was my carburetor being faulty. Now I know what to do and get my blower working properly. Thanks.

[@donnierobertson3088]

Great job again like always

[@firstman9273]

Hi, Is that Loctite 5923? Thanks for another excellent video.

[@primus108]

Another great video, with useful information. I noticed a slight delay in the sound when I played it. Not beefing, just thought you would wish to know that.

[@tomstepanowicz6191]

Thanks for sharing your knowledge.

[@guyin916]

i rebuilt a stihl concrete saw about 5 years ago. seals failed as a result from the crankcase bearings were missing balls. head+piston+carb as well. signs of straight gas. good times.

[@HOLLESjr]

Great Video, Thank You.

[@zx8401ztv]

Nicely repaired Don :-D Using a screw to help get a seal out was something i saw a long time ago, not sure who thought up the idea first but it's so simple :-D. Crank seals seem pretty reliable to me, i've only had one leak air into a small twostroke motorcycle engine, and it was an internal seal. While i was in there i replaced them all and the bearings, i never needed to crack that engine apart again.

[@snoopdogie187]

I have a kohler K301 which the front crank seal started leaking oil, it only took at around 8 or 10 years to have an issue. I am in the process of fixing that with everything else that was collectively wrong but too small to bother with on its own at.

[@michaelallen6645]

What are the carburetor screw settings for an Echo pb-500t blower

[@firstman9273]

Hi, what "aviation gasket seal" did you use? Thanks for another excellent video.

[@cerberusbonsaiarboricultur774]

"I didn't do a leak-down test" --- while I'll be googling that, I'd LOVE to see a vid where you go-over all the ways one can use a vacuum-gauge, pressure-gauge, tachometer, sprayed-fluid(checking for leaking-pressure a seals), not in-specific as if a problem was needing to be solved but in a context of yearly (or every 6mo) restorative/overhaul work! This "leak-down test" sounds like something of MAJOR value to me as I'm always messing w/ machines that were given-up-on, if I see a blower/saw/hedgers at someone's curb I almost always grab them, am loving getting-into this and pressure/vacuum is still a major blind-spot for me, haven't even bought a vac/pressurre gauge (just a tach&spline-drivers) because I don't know what I'd use it for, I mean I check compression by pulling the cord (and can't see any value in knowing the specific measurement value of the pressure in that case) but imagine this 'leak-down' test would un-earth SO many problems on so much of my equipment!!!

[@dwoodog]

Nice, keep cranking out the videos. Your a gold mine of small engine knowledge.

[@timtravasos2742]

I would never have suspected that. Not too difficult to fix either.

[@beerggls]

06:52 Dry seal against dry crank spindle = burnt seal = vacuum leak... ASSEMBLY LUBE

[@rpavlik1]

Great video! I've got a somewhat similar problem on an old homelite blower, but I'm pretty sure it's because I replaced the nasty fuel lines but the old ones were a weird size, so it's not sealing well against the tank.

[@freezefoot]

Really good video.I have chainsaw that leaks and has same symptoms.Time to explore the seal me thinks

[@tyroneclarke1666]

Thank you for sharing your knowledge. 🇦🇺

[@rogervonschleusingen4603]

THANK-YOU VERY MUCH SIR, STAY AWESOME AND SAFE !!

[@GrampiesWorkshop]

How's she goin'? Nice repair. The extraction on the seal was tricky!!! Well done!!!

[@metheewatchakittikorn4796]

Very useful information. Thanks so much for sharing your knowledge.

[@paulwharton1850]

Excellent - Very clear & helpful.

[@CJforUSA]

You deserve so many more subscribers....good work!

[@Smalltechguy]

So Donyboy, I don't have a Stihl, but this Echo is doing the same thing. I replaced the coil since it didn't have any spark. The machine idled fine but then took quite a bit to throttle up. I did just as you had done and just replaced the carb thinking that the jets were dirty and this carb was non adjustable. So even replacing it with yet another one it still does the same. I had pulled the flywheel just to make sure the keyway wasn't sheared, which it wasn't. I can't recall seeing any oil though at the crank seal...I'm stumped

[@pootthatbak2578]

Donyboy is correct to add rtv to seal he installed, my bg65 had red sealant all the way around both seals mating surface to block

[@JnC445]

I went through something similar with a bg86 stihl blower, when I was inspecting the seals they seemed to have been pushed out a bit rather than sitting all the way in as they are suppose to, after opening the belly pan it turned out to be a bad crankshaft bearing on one side. The metal piece that retains the balls inside the bearing grove was broken, replaced the bearing with a new one and the machine runs fine. I ended up using copper gasket maker around the belly pan and the seals.

[@jamesmullins3219]

good video. good tips, good diagnosis

[@JimFixIt74]

Great video Don! Have a great weekend.

[@trumpzilla4193]

Excellent advice and perspective - "it's not the space shuttle" LOL

[@MartyInTheWoods]

Yes, I just wanted to make this comment, but I saw you already did! LOL

[@THEMOWERMEDIC1]

Space shuttle specs Are as follows. Tighten flywheel nut till it gets loose and then back it off 1/4 turn

[@MartyInTheWoods]

@@THEMOWERMEDIC1 I think they have spare blowers in the Space Shuttle ;-)

[@MartyInTheWoods]

@@THEMOWERMEDIC1 hey cool! I just saw you have a great channel!... I might subscribe, even though I don't even have a mower! :-D

[@WJCTechyman]

Another youtuber says that constantly. "It's a lawnmower, not the space shuttle" when working on mowers. I watch both channels, Don is pretty straightforward and concise while the other is like Red Green meets Trailerpark Boys that knows how to fix small engines to boot.

[@bombadeer8231]

I use a dent puller. Wall board screw then lightly tap backwards pulling the seal like you would a dent.

[@johnbalasa711]

Nice demo thank you.

[@mrbottomfeeder]

You are the man. Thank you. Thank you.

[@connorjohnson9230]

+1 for spark arrestor removal, did the trick for me

[@flhusa1]

don't just remove spark arrestor . remove it clamp in vise grips on the edge and heat over gas burner stove or propane bottle torch to cherry red and use small handle wire brush and clean it till new. replace it and remember ONLY YOU CAN PREVENT FOREST FIRES !

[@barrybebenek8691]

Great tip with that one. Thank you for that posting. 👍🏼🇨🇦

[@garyalford9394]

My brother had one of those he bought new that would only run good with choke partially on, dealer couldn't fix , I found carb had wrong jet, apparently it was originally set up for high altitude we live in Northern Ind.

[@thomasadrian9854]

Great info- thanks for posting!!

[@WJHandyDad]

I have more trouble with leaf blowers than any other equipment - I usually end up buying a new one every 1-2 years because nothing ever seems to get them working - but I've never seen this repair - I may check that next time before I throw one away!

[@jensenwilliam5434]

Thank you!!!

[@spelunkerd]

Was the leaking seal allowing air to come in through the seal, effectively causing an intake vacuum leak?

[@cedricmerritt7664]

This dude is a beast

[@brucel.6078]

Nice.. i figured it'd be a clogged spark arrestor!

[@InTheDogHouse3DPrinting]

If the spark arrester was plugged, it would not rev up like that. In case you missed the video, the spark arrester wasn't even the issue.

[@dominoespizza1756]

spark arrester? is that the coil

[@MrMrfreedom1]

@@dominoespizza1756 Muffler area

[@thomask940]

@@dominoespizza1756 it's a screen prior to the exhaust entering the muffler. It's intention is to reduce exhaust temperature...to no avail.

[@dominoespizza1756]

yes ok I've learned what is

[@benventura5170]

great video thank you

[@bill154cub]

If the seal is leaking how good is the crankbearings? Great job donyboy.

[@GHULAMABBAS-bs4hy]

Very informative video

[@jimmydickson8854]

Thanks dony

[@888HUSKERS]

Amazing video!

[@RussellBooth1977]

I lube up the seal lip to stop it burning out on startup, when I was rebuilding a Stihl hedge trimmer, I bought both crankshaft seals for $15 AUD from a bearing shop. Yeah, never tighten up a flywheel with an impact wrench or else it will crack, on the larger mower engines you're better off using a torque wrench to tighten the nut up,the Taryl trick of removing them with a pry bar & mallet works in the Briggs & Stratton engines but I tend to need a 3 jaw puller on the Honda engines,the screwdriver,hammer & socket method also works on the Stihl engines. As far as oil seal leaks affecting how the engine runs, I had a badly worn rear main oil seal in a Nissan RB30 6 cylinder engine which was causing rough running & stalling at idle,in a Chevrolet LS1,it caused a slight power loss when the front crankshaft oil seal was leaking oil & air. So,it can occur in any internal combustion engine !

[@dirtyshirtinfo]

Great vid, thanks for posting. “It’s not the space shuttle.” An alternate is: “we’re not building a piano here.” 🙂

[@dkupy100]

Taryl Fixes All uses that line. Is Donny watching?

[@jay90374]

My boss told me that thirty years ago when I first started welding! LOL

[@dougsfan9984]

Thank you very much!!!!!

[@Blackford86]

Sir have you ever worked on a Husqvarna riding lawnmower/snowblower my question is how do you change your snowblower unit off and put the mower deck on do you have any videos on that

[@pastormike5054]

Very good content 👍💯 Thanks

[@zalmianuar41]

Very goods video. Helpful.Thankyou

[@tom.p1986]

I have the same blower but have the opposite problem. It bogs down when cold but once it warms its fine

[@ryanfrankum3493]

Hey how can you fix a leaf blower won't stay at idle thanks you have a good day hope to hear back from you soon

[@jamesconnors5653]

Thank you.

[@suec4630]

Thank you!

[@bpestcontrol1926]

Great content as always. Many thanks.

[@CentralNH]

What are your thoughts on bg86 vs echo 2620. Which is easier,cost effective to work on echo vs Stihl?

[@clauslundberg9224]

Super nice fix - DB73 quality video