FUEL TANK VENTS AND WHAT YOU NEED TO KNOW (funny blooper)

Fuel tank vents can cause a plethora of run-ability issues. Today we will address what happens when a tank vent fails #Stihl #Vent#SmallEngineRepair #EchoI

[@goodboyringo9716]

I think this is why my Scag Turf Tiger 29hp DFI to cut out. I haven't check it yet because I just found your video but thank you very much. I'm sure this helped a lot of people.

[@travismauldin7194]

Sounded like Jabba the Hut from Star Wars in that blooper.😆😆😆😆

[@adnacraigo6590]

Outstanding advice.

[@RayofallTrades]

Great video my friend. Very thorough

[@GeneG-wk2mz]

Man on man that fresh cut thanks

[@joeortiz3455]

Awesome lesson now I know why I have seen fuel leaks where I have thank you sir ! One more step closer to the mower medic 1 small engine diploma

[@LowkeeLT]

Very informative, thanks!

[@jimmydickson8854]

These machines are great at what they do ,but they are finicky at the same time ,old jimmy follow you from Australia

[@aerotech1bob]

That is a great video, it was helpful thanks

[@magicone9327]

On old 028WB, the tank vent originally was two fine treaded inserts specifically located. These would allow for tank pressure to equalize. The newer vents seem to only allow air to pull into the tank to eliminate a vacuum. Are the older original carbs incompatible with the newer vent function as the tank pressure can get quite high and put a lot of fuel pressure and possibly more volume into the carb per each sequence of the needle opening,

[@dalebrannon724]

Thanks for this information.

[@rgw1981]

Excellent video

[@RaleysSmallEngines]

Very good job explaining every step of how it operates

[@AnotherUser1000]

Especially at the end... 😄

[@nathanwindle9816]

Thanks i never knew thet the tank pressure or vent was important !! Or what acures when its not right ! Got a few old saws that will visibly leak fuel from vent ! Still use them when needed always figured saw isn't quite working right but just put it down to been a old tired machine!! Got to get myself one of them pressure/ vacuum testing gadgets and give the old veterans some tlc

[@motoman5023]

Be careful with some of the Echo trimmers in the line where the fuel vent is there is a small white filter if it is restricted in any way it will starve the fuel system I know this because we had one at the dealership here that was partially plugged and it would starve the engine of fuel after running for like 45 minutes it was extremely hard to diagnose

[@bushmaster2936]

Thank you

[@Funlu]

great info

[@buddymcburnett3011]

Hello, what's the best after market carb for my Stihl FS110 WEEDEATER, thanks for your help and time my friend ! ❤

[@franknorton8140]

Brother thank you I'm having that very problem

[@TheRustyRooster]

Thank you sir I always struggle wither or not the tank is venting properly always 2nd guessing myself on hand held equipment over this.

[@RaleysSmallEngines]

Get back to work Rooster Lol

[@dfu1685]

Soo I am a little confused because it is not clear what the overall function of this part is supposed to do when it is working? Allow air IN or OUT?

[@exinanition2307]

What pressure/vacuum pump do you use? Could you post a link to it and where to get one, please? Thank you!!

[@myke_bota7590]

I just picked up a new Stihl tank vent and when applying vacuum, it only holds momentarily the starts slowly dropping pressure???

[@jonathanechols9985]

How do you determine of it is the vent or the fuel cap?

[@willssmallenginerepairllc5060]

Had a faulty tank vent on a BR340, replaced it with an OEM one but was still having fuel starvation issues, installed an Echo one and it hasn't given him any trouble since

[@LostPlanetLuvr]

My echo srm 210 is having same issue. Starving for air, replaced check valve 3 Times. Still bogs down unless I open gas cap.

[@davidgunter7162]

I got brand new FS 91 stihel with a bad vent, back to shop 4 times before they figured it out.

[@barneymm2204]

You seriously need to do a Dr. Evil.

[@curby01]

So would it cause my engine to shut off after running for about 10 minutes? Then also make it hard to restart I have to let it sit for a few minutes before I can restart.

[@johnclarke6647]

I pressure test the tanks and fuel lines in chainsaws the same way. I plug my Mighty Vac into the fuel line going to the carb and pump it up to 7#. It better hold. If it holds, I switch it to vacuum and pump it up. It should gradually release. If it does not hold pressure, there could be a leak in the fuel line, tank, tank cap or a bad tank vent. I start looking for the leak with spray soapy water.

[@nevinkuser9892]

smart

[@RyGuy1784]

so i’m have a problem with some stihl weed eaters the vents keep going bad, I put a new on on it runs for a few weeks then the vent fails. what might cause that?

[@grandmasterchody]

I've been searching everywhere for this information my 03 tahoe had a evap hose break on it and I couldn't find any information about evaps

[@johnclarke6647]

I test my gas tank with my Mighty Vac. I plug it into the fuel line going into the tank. It should pressure up to 7# and hold at that pressure. If it does not pressure up, there is a leak, somewhere. I will use a spray soapy water mixture to find the leak. If a tank does not hold pressure when the gas gets hot it will boil in the tank and cause a lean condition in the saw. After it passes the pressure test, I switch to vacuum and pump it up to 7-10 inches of vacuum. It should gradually reduce to zero inches of vacuum as the tank vent allows outside air in. If the tank vent does not work correctly, the carburator will not be able to pump gas against the vacuum in the tank. You will also hear a “who’s” when you open the gas tank.

[@THEMOWERMEDIC1]

I know 👍

[@donkeydiehard879]

So via the stihl technical it says ti check the valve with gas cap on and the inlet plugged and vacuum pump hooked to return. It says there should be no vacuum build up and should hold pressure. Thats the opposite of what you say in the beginning. Im a little confused.

[@patcassidy2019]

I have a John Deere 345 r zero turn . I can’t get fuel into the tank . I have to sit for a min and keep adding gas . It always acts full but I have to keep adding fuel . Do you know why that would occur ? I’ve watched 80 videos and nothing addresses this problem . The mower is off and I have to keep adding gas ? Help , please

[@TheGameBoy56]

What name of that tool I can find brake bleed but not a pump Is there model number for that tool

[@691lucian]

Or if it dies after a carb rebuild or replacement you can always just unscrew the cap, re prime and try it with the cap off, if it runs fine without the cap then its a vent issue

[@ShainAndrews]

Yes. KISS method.

[@marshallborder9089]

Had to replace one of these STIHL tank vents , wows expensive. ( EBay )

[@noejunior-nocode]

Anyone know how to test it for folks who don’t have one of those pump gauge dohickies?

[@roadsidecamper]

Gas is coming out my carb like the bellagio fountains in vegas.

[@joeclark9042]

where do i get one of these black vents can any one help me please thank you

[@timnels8638]

pardon my question here, sometimes I'm a little slow. So i'm having issues with my Stihl FS91R like it is starving for gas, at 1st it only did this when the motor got hot, now it will not run longer then 30 seconds. When I remove the gas cap I get woosh of air, believe it is vacuum lock. Don't have compression tester but would this be a sign of tank vent needing replacement. Thanks for your teaching work. Tim N

[@kellismith4329]

Easy test is to disconnect the vent and try restart

[@ondago2]

Was just riding my 1996 GL1500 GoldWing. Late night, heading home through a wooded desolate park. Motor was fine and always has been . Just criusing along and withno warning, motor bogged and then died. I pulled over and thought what to do. (Tank was full and I knew it for sure, because I'd filled out last night before garaging. I cranked and wouldn't start but did try Then set full come and it did eventually start. Futzed with throttle and come and got it running again. Staked 5min later. Starting was getting battery drained but got it, drove out of woods. Still thinking "what the hell"? Rinse repeat a few more times. Few miles/ stalls later, I got to gas station. Got carb cleaner and a half gallon of gas to confirm and get fresh. I had begun to think, "what changed and what could I have done when I fuels last night?". "Gas cap? Fuel line? Vent line?". Sure uff, opened fuel door and I had thought looked the vent line. So finished riding home. WOT, anything, didn't have problem going last 8 miles. So, I figured, KZbin up some vids on the vent line and stallinng. 3rd vid was this and near the end, you confirmed not only the effect of vent line "clogging" but also, that is gotten my 30 miles ok riding since filling track last night.

[@M1keplaysgames]

if somone could tell me what valve that is i realy need it please and thank you

[@Draega007]

My gravely pro turn 152 gas tanks make a intermittent whistling sound throughout the day when it's hot. Is it the gas caps causing this or is it normal for it to do this?

[@THEMOWERMEDIC1]

Normal. Might make Sure the tank vent in the cap is not partially plugged

[@Draega007]

@@THEMOWERMEDIC1 ok thanks I'll check that out this evening.

[@johnclarke6647]

I pressure cheviot my complete fuel system to 7# and 7inches of vacuum. I pressure check carbs to 5# and 5 inches of vacuum. I check engines to 7# and 7 inches vacuum. The Stihl service manual says they can drop one pound per minute but cannot drop below 4#.

[@THEMOWERMEDIC1]

I don’t care with a manual says I want zero leakage

[@johnclarke6647]

@@THEMOWERMEDIC1 you won’t get it on an ms 440 or 360. You get a gradual leak down to 4#. This is because the oil pump spacer plugs into the pto side seal. Husqvarna has a recess on the 372 where they install a small O ring but Stihl does not and you will get a little pressure loss. I talked with my local Stihl tech and he told me the spec and my 440 passed that spec. He told me not to worry about it. On the 440 the pressure loss is between the spacer’s inside dimension and the crank It does not leak around the seal. I sprayed it good with soapy water and got no leaks. As the saw warms up and the clutch and oil pump are screwed down this little leak probably also stops.

[@SuperMulletguy]

Is a symptom of a bad valve a LOT of vacuum release when I remove the gas cap? I'm having runnability issues on my FS131 Stihl trimmer and it bogs out, loses power, then its hard to keep running. Opening the gas cap and WHOOSH, TF is that?.. I replaced the spark plug, fuel filter, air filter and just run MotoMix. Should I just replace the valve? I don't have the fancy pressure gauge testy.

[@THEMOWERMEDIC1]

Absolutely you are on the right track

[@SuperMulletguy]

@@THEMOWERMEDIC1 dude it worked. That valve was shot and the replacement got it running like a champ.!!.👍🏻🔥🔥

[@brentkelly5445]

Do you know this issue of a Stihl not wanting to start especially after running for awhile and being stopped for a bit. or when the temperature goes up into the 30's or machine is sitting in the sun. Is this something to do with the vent of fuel circuit? Has something to do with heat and fuel/vapour. usually have to prime it then but that isn't enough. Something that helps is I have to hold throttle while starting.

[@THEMOWERMEDIC1]

Yes it’s called static flooding

[@brentkelly5445]

@@THEMOWERMEDIC1 is it one faulty vent. or does the fuel port need to be changed as well

[@THEMOWERMEDIC1]

@@brentkelly5445 check vent. If Good Replace carb

[@mowtoegee7049]

All my Stihl machines do this. Every single one. The 4 mix ones (KM131R) are the worst for this. Yes throttle fully open helps. Sometimes I have to remove the spark plug and manually deflood it. I also keep them in the shade when on site so they stay cool and also, NEVER store upside down! always upright :)

[@shermankearns200]

AHHHHHHH! I got it!

[@THEMOWERMEDIC1]

That’s what I like to hear

[@joeortiz3455]

Well how about that it works like a diode kinda !

[@THEMOWERMEDIC1]

No not quite, a diode requires a minimum of .0127 amps to operate. This is not an electrical part

[@joeortiz3455]

Thank you for explaining that ,with that learned it is meant to keep atmospheric pressure out of the fuel cell?

[@ralphcampbell7180]

Gas tank don’t have one

[@nashguy207]

Would this also work for 2 cycles that vent through gas cap?

[@THEMOWERMEDIC1]

Yes same procedure Air in but not out