Harbor Freight air compressor not starting fix

I will be posting more videos about these air compressors.
COME ON PEOPLE SUBSCRIBE!!!

[@mechanicalking]

kzbin.info/www/bejne/oH29p4VtZpt7p7s

[@embie5119]

Thank you! You have no idea how long I've been dealing with this issue on my Husky compressor. It would turn on just fine when the tank was empty, but once there was pressure in the tank it would just hum that 60Hz tune we all love. I checked the check valve, I checked the unloader, I replaced the capacitor, and I have read everything I could find and watched every KZbin video I could find. I was starting to give up hope and go buy another compressor. Instead, because of your video I just pushed that little pin in with the tip of a screwdriver, turned it on, and BAM it worked. And as an added bonus somehow by doing that I dislodged whatever it was that was preventing it from working properly and now it's good as new. You rock.

[@mechanicalking]

Awesome

[@BLOWbamasux]

Fixed mine just by pushing the brass pin down with a screwdriver!! Thank You for this video!! Mine is just over 15 months old & I REALLY like my 20g McGraw!!

[@andyd_9]

Thanks for posting! I just bought a small 20g compressor from HF and this fixed my issue...I just replaced the cold start valve with a better one and voila, cold start issue not an issue anymore. Saved me the hassle of returning it and having the same issue with another one!

[@jeffmatthews9125]

Thanks Dude! You are the only one after searching all over KZbin that fixed my no start problem.

[@mechanicalking]

Glad I could help! If it starts doing it again, you can put your hand over the intake in it creates enough vacuum to get it started.

[@sheriaken5144]

Great Video!! I was about too buy a new compressor and now its working - thanks to you. Keep the videos coming.

[@mechanicalking]

Glad I could help!

[@760Evan]

I just took the o-ring out of that valve and now it starts up every time.. no drilling, no grinding, no unnecessary modifications. Take the o-ring out, that simple

[@adamc3360]

I took mine out. Didn't help

[@evackesvidsandstuff1553]

Yep, that fixed it. This man is the real hero.

[@daveladd7046]

Nice job - exactly the steps that anyone who wanted to investigate would go through. Thank you..

[@chrismechanic6164]

Glad I saw this. Been having that trouble with mine since the day I bought it.

[@enriquemendoza8209]

This is the best idea ever. I have been thinking of selling off my compressor but now, I'm gonna try this fix. Thank you so moch.

[@bill4639]

No dude. This video will destroy your air compressor. Not a joke

[@p.chuckmoralesesquire3965]

thanks for the upload, great video

[@drodriguez3935]

Yeah, I agree. I recommend them as a mobile burn pit. I cut the top off of that same one.😂 after a long day at the range, and hitting it with double ought buck for ventilation holes. I love it🇺🇸

[@pengkha7576]

I bought the Mcgraw compressor at harbor freight as a return refurbished unit for $125. It would charge all the way up then trip the breaker. I flipped the breaker back on and let the air out to 90lbs and the motor struggled to automatically turn on and b it would trip the breaker again. I figured out that if I pressed and hold that starting valve it would fire right up. When I tried to loosen the valve it was on incredibly tight. I know it has goop on it but it shouldn't be that tight. I took it off and inspected it. Put tape on it and tightened it to just snug then a 1/4 turn. Ran it for a while and it worked just fine. Im thinking they are being over tighen causing them to bind? But that worked for me and b I got a nice compressor for an excellent deal!.

[@davidpage1692]

I fixed mine by removing the valve, verifying it came on without it, then when I reinstalled it, I went 1/3 of a turn past finger tight instead of cranking it all the way down. Works great now, no other mods needed. If it loosens up, I'll probably use some thread locker.

[@mechanicalking]

Cool

[@oggwop6724]

You are right, I use your method to test if the value was the issue. It cranked up like it was brand new. I'm going to replace the value and the air filter now, omw to HF

[@VentureWelding]

This guy's awesome! He included all his failed ideas, love it!

[@bill4639]

No, this is NOT a good video.

[@AllLiveRounds]

Thanks so much! Was thinking it was electrical. Rigged a valve with a handle on mine, I would not suggest that it gets extremely hot, but it will do until replacement gets here

[@mechanicalking]

Cool!

[@eddie577]

Nice job. Every tool I have bought from Harbor Freight to just use around the house I either had to fix or throw out. Compressor, Nail Gun, Heat Gun, Oscillating Tool, Drill, and more. I'm done with Harbor Freight.

[@TheButterflyGirl7]

I just bought at Christmas. The 20 gallon oil lube McGraw vertical air compressor only used it once. I went out there to use it today and it will not start! It is not the outlet which is a 20 amp and I double-checked it. This video shows an older unit. Do you still think it could be the butt connectors even in a newer unit? So upset. Thank you!

[@arlothudpucker7960]

Another cold start valve for this compressor is: Interstate Pneumatic Manufacturing 1/4" NPT 1.7 bar / 25 psi CVS7045 about $7

[@mechanicalking]

Ok thanks

[@israelquintero3118]

Where can be bought ?

[@markschuh2536]

Harbor Freight 8 gallon compressor. I read that you can replace a faulty check valve with the following; DeWalt D55168 Compressor Drain Valve # N000986 My valve just needed some lube and it worked fine. If you use the replacement part, you will have to open the valve to start and close to build pressure. I also had a SECOND issue. Compressor would not build past 55 PSI. Would kick the compressor off and/or trip the breaker. After much research, I read that these compressors do not do well with an extension cord. I plugged directly into an outside GFCI outlet and it built pressure up to my 120 PSI setting. Booyah! I had two separate issues and both are fixed. I may try another extension cord but a much much better gauge wire and shorter length cord. That may do the trick. Having the unit near an outlet is not always something you can do for your compressor needs.

[@bill4639]

Thank you for the part number

[@imetr8r]

I had a problem where my 21 gallon HF compressor would only run about 30 sec. before tripping the on-board breaker never going above 50 PSI. I had replaced the original oil and put in the correct amount of new oil. It look like it was just to the fill line, but apparently, its difficult to get all of the old oil out and the fill line is not very accurate to the eyeball. I solved this problem by draining about 2 ounces of oil from the case. On the next start it went directly to 125 PSI.

[@DADSGETNDOWN]

No down side to not using an air filter. Lol. I seen your 4bbl spacer, you should know the damage it will cause to the Cylinder.

[@gordonwilloughby8793]

I came up with an idea to automatically drain the water from the air tank that should work to replace the pressure relief valve you are fixing if the valve is beyond repair.. i used a solenoid valve and delay shut off timer I got from E-bay. i connected the valve to the output of the delay timer. Then I connected the timer input to the pressure switch so it would open the valve as soon as the compressor started. I set the delay time on the timer for 3 seconds. It works great to drain the moisture from the tank. When the compressor starts it opens the valve for the amount of time the timer is set for then closes until the compressor starts again. You might want to set the shutoff delay a little longer for the startup pressure relief on the timer.

[@VADLRO08131985]

Could you post a link from the valve you got. Thanks.

[@gordonwilloughby8793]

@@VADLRO08131985 It has been quite a while since I set this up. I am not sure where I got the valve or which one it was. I believe it was a 1/2 inch solenoid valve. You will need a timer to shut off the valve after a few seconds. Make sure the valve is the same voltage as your compressor runs on. I think this one would work if the compressor runs on 12o volts and the valve is the right size to fit the pipe on the compressor. Easiest way is to match the valve voltage and size to the voltage and pipe size of the compressor. Also use a valve designed for air for the pressure you are using. Don't get a low voltage dc valve or you will need to use a power supply to run the valve. Let me know if you have any questions. This valve is 1/4 inch but gives an idea of what you might need if it isn't the right size. www.ebay.c/itm/272758667081?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20131231084308%26meid%3D763f2ad0da804631a54c1acbba07b030%26pid%3D100010%26rk%3D1%26rkt%3D12%26mehot%3Dpp%26sd%3D292304810387%26itm%3D272758667081%26pmt%3D1%26noa%3D1%26pg%3D2047675%26algv%3DDefaultOrganicWithAblationExplorer&_trksid=p2047675.c100010.m2109

[@DukeLaCrosse20]

Before anyone goes through all this, I HIGHLY recommend trying a different electrical socket on your house, or if you're using an extension cord, try without it. In my case, my brand new unit works fine with a nice heavy extension cord, but will NOT start with a longer, skimpier extension cord. Of course, it starts even better when plugged directly into a wall outlet. I suspect that the capacitor under the fan cowling is under-designed. Perhaps someone with an EE degree can tell us if replacing the capacitor under the cowling with more farads would help, but for now I am happy to use a heavier extension cord. I can also imagine that if your capacitor is getting a little old, perhaps its lost some oomph? I really think addressing this issue from the electrical side is better than grinding away on brass parts.

[@StndbyHD1]

10/10 can confirm this instantly solved my sluggish no start motor literally just unplugged it from extension and rolled it over to the wall plug fired right up. Why has this worked all summer since moving into this new house but as of Tuesday I discovered it wasn't firing up?

[@cslloyd1]

Maybe the viscosity of the oil is higher in cold weather. Other comments in this thread do mention oil levels and viscosity as contributing to starting problems.

[@rebecaroman140]

hey king. The pressure relief valve (the pfffft sound when the motor shuts off) is broken, a friend tried to repair it, but failed. It's inside the little black control box. He may or may not have messed up the control box as well, while getting the valve out. can you made a visi video to help fix it!

[@rebecaroman140]

my email is [e-mail]

[@mechanicalking]

That noise comes from this valve the air comes from the compressor pump straight into the tank with no connection to the gauge cluster (stop/start psi control box) it may sound like it's coming from there but it's actually coming from the valve because there is a check valve on the fitting that connects the metal pump hose to the tank and when it shuts the pressure in the metal hose has to go somewhere so that's where it goes. And yeah here's a video! ;)

[@buster612003]

look at the engraving on it. says 1.7 bar? @ 1.7 bar that valve closes. its a pressure compensated valve, kind of like a pneumatic soft start here. once it builds up 1.7 bar that valve closes, and stays closed. it takes 1.7 bar of pressure to overcome the spring, and once it hits pressure, that piston overcomes the spring and seats against that o'ring. before it hits 1.7 bar the valve is open and venting to atmosphere allowing the compressor to get up to speed before it starts seeing a load.

[@mechanicalking]

Yes I know the one on the other compressor sealed too easily.

[@buster612003]

sorry, was just throwing out some pneumatics theory lol. glad you filled in the holes ;-) actually it is more a check valve since it only has 2 directions, just doesnt let anything higher than 1.7 through

[@ajbrown2013]

Thanks Ed c I didn’t know how these worked I started mine up and noticed it leaking and thought mine was broke that’s why I searched for this video to begin with lol guess it’s working as it should

[@danielweese2085]

My valve thingy is sticking out and when I turn the compressor on I only get humming for 3 seconds then it shuts off. The valve is sticking out, it can be pulled out further by hand and is springy but it doesn't move when the compressor tries to come on. I'm not sure what to do.

[@mechanicalking]

Step 1: Unscrew it all the way Step 2: thread it in 1/2 turn Step 3: turn it on Step 4: hand tighten it quickly while its running and repeat when its cold again

[@mechanicalking]

It lets the air out until it gains momentum

[@danielweese2085]

Thankyou. I went back and took off the plastic cover. Instantly I saw that one of the wires had come loose from the silver cylinder. Tightened it up and she's running fine again!

[@mechanicalking]

Cool!

[@llcoolg7028]

I can see the engineers at (insert harbor freights labels) taking notes lol

[@samwilloughby5512]

Thanks

[@mechanicalking]

No problem! Hope it works out

[@MrsBuddevil]

What's the extra set up you have an your tank? Filter?

[@mechanicalking]

I believe it was just a extra 11 gallon tank and no filters

[@billmadle1235]

You can buy one for eight dollars online.called cold weather start valve.

[@1512romeo]

My circuit breaker was tripped on the compressor itself. Easy fix 👍

[@bill4639]

The compressor has an electrical circuit breaker? Where?

[@1512romeo]

@@bill4639 mine is on the right side if your facing the compressor. Under the air filter

[@core251]

Thanks for this video. Call me an idiot but I couldn't find that red reset button (my garage is dark in the corner). Silly me!

[@mechanicalking]

It should be to the left of the plastic Perpendicular to you when you're looking at it from the front. It's mounted to aluminum. It's not easy to see unless you look at it from the compressor side.

[@core251]

@@mechanicalking Yeah I did find it right after watching your video. In my case though my problem is almost certainly mouse damage (I'm on a farm). The mice like to make nests under that plastic shroud on top and every time I turn it on, mice bedding (and sometimes mice) come flying out everywhere. I'll be pulling it apart today.

[@carlfalk7251]

That's not a drain plug: it's a sight glass to see the oil level in the crank case. It should never be removed. Looks like your plug is directly under it. My plug is on the right side, with sight glass facing forward. Also, what is that gray tubing that goes under the case to the other side of the head? Did the compressor come with that? And with the pressure relief valve too?

[@mechanicalking]

The pipe that goes the the cylinder head is where the air goes into the tank. Yes Most air compressors come with a pipe coming off of the compressor so that way they can supply your air tools with air. The other tube goes to the pressure sensor. If you're talking about the blow off valve, that is on every air compressor. Yes, It did come with it. It is required to prevent an explosion. If you mean the cold start valve, yes it did come with that, or else it wouldn't start.

[@otoniel780]

I have question my compresor runs good when is empti to fill up but when I use the air cam down and the compresor try to start the swich from my home or box switch shut down and the compresor have to empty to runs again thanks

[@mechanicalking]

Try a different plug/outlet

[@bill4639]

@@mechanicalking you are absolutely an !d!0+.

[@bill4639]

You have to replace the COLD START VALVE on your compressor. Buy one on Amazon in 1/4 inch NPT size. If that’s not it, replace the REED VALVES inside the cylinder head. Last, it may need a new capacitor. The microfarad rating for the capacitor is written directly on the old one.

[@T_2_the_ravis]

My problem is I go to fired up in the morning and it keeps blowing the breaker. It'll start compressing really slow and blowing the breaker each time. I try.

[@mechanicalking]

Take the air cleaner off and hold your hand over it it will create a vacuum that will allow it to start and then take your hand off of it once it starts it has to be a tight seal on your palm. The air filter is not necessary unless you are working in a Dusty area

[@rascosgoldenlife4921]

Mine turns on and gets about to 50 psi then shuts off or the red fuse jumps and shuts off and won’t turn back on so I have to open the valve on the bottom and release all the air and then it will turn on again. Any suggestions on what’s wrong with it.

[@mechanicalking]

It sounds like your on/off psi is out of whack if it shuts down at the same pressure every time. There's videos on how to adjust it

[@Thumper68]

Took out fuse on mine it’s cheap also little lighter weight oil helps start up especially in cold. Also you showed a female spade connector a butt connector is open ended barrel shape.

[@ajbrown2013]

Thanks for that too been doing diy electrical work adding light bars and building robots and what and I was not aware of the correct term for that lol it’s funny I just say I need one of them thangsmagiggers usually when my sons helping me do projects thank you I learned something

[@Thumper68]

@@ajbrown2013 lol well when we working with our old man we all know what thingymigerrs are lmao! After awhile it just is a grunt then nothing cause the other persons waiting already knowing what you will need! :)

[@mattunknown7070]

Have the same one and I have a problem. It will fire up and start pumping and sometimes it will work and most the time it won’t. But it will start pumping and when it acts up it will shut off pre mature. Then I have to reset the control and hit the reset button and it may pump for 10 seconds and sometimes it will pump for 5 seconds then do the same thing. What do you think it could be. Do you think my trip switch is bad

[@mechanicalking]

Yep it sounds like it needs to be returned to be honest. First try a different outlet plug in. If it still does it then get a new one.

[@mechanicalking]

It's either a cheap breaker switch issue or the motor is not right and it's pulling to many amps

[@kaneetsate1662]

Did you ever find out what was wrong with it? i have the same problem

[@mechanicalking]

If its pulsating up and down before it shuts off then its not the breaker, it's your cold start valve which is basically a flow activated valve that engages when the compressor gets to speed, you need to keep it from popping up by holding your finger on it and once it spins up to speed let go. You'll see it move when its trying to start, also make sure that your cord is plugged directly into an outlet.

[@RoloisRight]

Good tips about checking the capacitor connections and the valve. It's called a cold start valve and sometimes you can fix it without removing it by simply hitting it with some WD-40. If that doesn't fix it or if you live in really cold temps, amazon has one that's confirmed to work on the hf 21 gallon, search 65234R3FA729674 (but I'm sure any brand works).

[@mechanicalking]

Cold start??? Really??? Hahahaha It was 72°F.. lol I'm pretty sure they're called a compression release valve. I just wanted to show my way of getting it to work. There are hundreds of ways to do it another way is just to push on the top of it with a screwdriver.;) Thank's for watching!

[@RoloisRight]

mechanical king Compression release valves are on engines, this valve is a start valve. "Cold" is just something that became common to the name and doesn't mean it's solely for cold temperatures. Yep, I agree, there's many ways to remedy the problem. I just thought your example might not be easily reproducible by everyone having this problem so I figured I'd suggest spraying some WD-40 or ordering a $6 part (also seen on ebay as cheap as $4) as alternatives which may be more practical for some.

[@mechanicalking]

I'm surprise that's what it's called. Thanks for the comment!

[@mechanicalking]

I will try the WD-40 on the next one if it happens again, thanks.

[@troy9864]

WD40 did the trick for me.

[@johnysilver1853]

My compressor starts working and builds pressure up to 150psi but sometimes during work it will not start and won't keep tank charged. Sometimes it turns on only for a few seconds then goes quiet. Sometimes I hears something that it wants to start like air going somewhere through the pipe for about 2 second and then quiets and stays like that. Fails to keep up pressure in tank when I use it. Pressure goes low as 50psi but compressor doesn't start. Then I had to open drain valve to release remaining air pressure in the tank. Disconnect it from AC power for few minutes and it starts working again build up to 150psi again. I don't hear any air leaks. What could be wrong?

[@mechanicalking]

What model compressor?

[@johnysilver1853]

@@mechanicalking Husky 20 gal 150 psi. Model 947265

[@mikedeiana1504]

It’s a shame to still having a problem with the same little release thing that’s been a problem for like six years

[@hectorcastilla5913]

Hi, I am having the same issue with my compressor, it is exactly like this one, I ordered a 1/4" npt cold start valve from ebay, but when I try to thread it it, it seems to fit tighter than the original CSV and I am afraid to cause damage to the threads on the head of the compressor, should I just continue to tighten it or do I have the wrong size valve? Thanks...

[@mechanicalking]

Hector Castilla does the valve you ordered have tapered threads that get thicker the farther in you thread it. If so just threat it in until it's tight enough to not leak but don't crack the compressor. If your thread count isn't right then it will be a very tight fit. Just eyeball what the threads look like on the inside and compare it to the valve you bought and see if they're similar.

[@mechanicalking]

But no matter what you need some Teflon tape

[@hectorcastilla5913]

mechanical king. Thanks last night I went ahead and used a male to male coupler to put in the compressor head and then used a female to female coupler to put the csv in and it worked out pretty well, i was able to tightened everything out turned on the compressor and went through several cycles of restarting it by using air and the thing started right up everytime, it seems the new valve did the trick, thanks

[@hcastilla2010]

Hi, I replaced the cold start valve and now it starts everytime like a charm, but I have another problem, when I installed the new valve, i accidently overtightened the valve and one of the edges of the head cover cracked about a half a centimeter, it worked well, no air leak at all, the new valve is set almost all the way in, I went ahead and covered the area with jb weld and some liquid steel putty, it dried hard as a rock. I really dont know how much pressure builds up on the head cover in this section where the cold start vakve seats, do you think I will be ok?

[@mechanicalking]

@@hcastilla2010 if it doesn't leak and as long as the J-B Weld doesn't get extremely cold or exposed to Sun then it will be fine

[@houseoffire72]

I have a HF Fortress ultra quiet 175 psi compressor used maybe a dozen times. Fills to 120 psi then motor shuts down. Unplug wait five mins plug back in and fires up building pressure to 130psi then shuts off again. Wait fives minutes builds pressure to 140psi... Etc... Cold start valve is working each time...

[@mechanicalking]

Seems like a thermal breaker is getting tripped if your outlet is working right. I just got the fortress 200 psi and I noticed that they may not be fast but they sure are more efficient with the energy they use

[@houseoffire72]

@@mechanicalking I have new service to the shop. Plenty of power. That's exactly what seems to happen, the thermal reset is kicking in but why is my question... I played around with the cold start valve seems fine, also checked the pressure switch. Tested by turning the screw to increase pressure cut off. I did kick in but then the thermal breaker tripped... I will order a new cold start valve & pressure switch.

[@mechanicalking]

It might need a new breaker

[@houseoffire72]

@@mechanicalking Cant see one located anywhere. Must be internal ?

[@mechanicalking]

@@houseoffire72 yes most likely an auto reseting one somewhere

[@fordguyaj5581]

Is it normal for some air to blow out of that valve the whole time the compressor is running? Or should there be no air coming out of that valve after it gets going?

[@mechanicalking]

FordGuyAJ no if its working properly there should be no air coming out when the compressor is on

[@fordguyaj5581]

mechanical king ok I didnt think so , mine must have something wrong with it cuz it blows air .. thanks for the reply

[@Avalanche2]

Mine does the same - these are junk for the most part, very disappointed in it.

[@phillipwheeler809]

New cold start valve $5.99 from Wally world.

[@ronaldbertin9455]

That valve is about 10.00 to replace

[@mechanicalking]

Thats great

[@Lilmiket1000]

lol, the screw below the oil window is the drain plug. not the actual window!

[@Lilmiket1000]

Be careful with these things. if they get too hot they will catch fire! wouldn't bother with an extension cord and use a 20amp circuit.

[@mechanicalking]

Yeah

[@mechanicalking]

Thats accually kind of funny that I didn't realize that until now. Lol

[@cslloyd1]

I actually called Harbor freight tech-support and they said you could use either the window or the screw. I think this is WRONG. You shot NOT remove that window.

[@chuckfischer7202]

Unloader, it's called an unloader.

[@craigchiddo2794]

I have a kobalt quiet compressor that does the same thing

[@Avalanche2]

Bought one of these a few weeks ago - they are junk, very disappointed in it. I should have bought the next model up with the real piston engine. This is an odd oil-less/oiled hybrid, very loud and very weak.

[@mechanicalking]

The compressor in the video has a piston in it and I've seen it in person and it seems very real to me. These compressors use an oil dipper set-up... If you are talking about a stand alone gasoline powered compressor, obviously a cheap indoor shop compressor isn't going to match an outdoor compressors performance. I personally am not disappointed because my air is compressed very nicely and at high pressure. :D

[@dudleydorite7678]

I fixed mine by switching to geico

[@MrPatkline]

How to fix reed valves in your Harbor freight compressor kzbin.info/www/bejne/roLVaH-Fjc2Sn8U

[@camboss1371]

omg this is what not to do. small grind or big grind WTF

[@AXNJXN1]

12 minutes worth of 'research'... And you could've bought this for less than $8.00 on Amazon...

[@facereader99]

Is there a more pure time-wasting video on this compressor on KZbin? Probably not.

[@DapperCut]

You confusing and hard to follow what you are doing or saying.