Air compressor troublee shoot question

[MasseyWV]

You got me..Capacitor? where? At the start switch? Ill try all the suggestions tomorrow am.

Most air compressor motors have a start/run capacitor to help the motor start spinning. The description you provided leads me to believe the start capacitor is bad. I've encountered and repaired this problem many times. Judging by the pictures you provided, the start capacitor appears to be the long black cylinder located under the compressor motor, the one with the yellow wires coming out of it.

When replacing the start/run capacitor, it's important to replace it with one of the exact same type and rating. In most cases it's ok to go a little over on the microfarad (uF) rating but never go below it or the voltage (V) and temperature ratings.

Lastly, I second the advice about not running an air compressor using a long extension cord. The resulting voltage and current drop is simply too much for most air compressors to start and/or run properly.

 

[kenmac]

You got me..Capacitor? where? At the start switch? Ill try all the suggestions tomorrow am.

The black round thing under the motor with 2 yellow wires

 

[alchemysa]

The capacitor usually just helps the thing get started. If you give the fan a spin it should run even with a faulty capacitor. If it starts with a nudge then yes the capacitor is probably faulty. Could also be seized bearings or gunk in the motor. Or a seized pumping piston. It looks just like mine. They do require oil for lubrication, it goes in that red capped plug hole behind the black switch box. Have you checked the level? They usually have a sight glass.

 

[Grumpy Old Man]

Thats a harbor freight compressor ,I've fixed and sold hundreds of them ,and yes it has a sight glass for the oil level and since these are "splash lubricated " pumps you should keep the oil level high (I recommend keeping the sight glass full with straight 30 non detergent oil ) The problem with yours is the pump is frozen and can easily be fixed by removing the fan blade and rotating the shaft forward and backwards with a set of vise grips , taking care not to scar the shaft or groove for the retaining clip .these aren't bad little compressors for lite duty /tires and can be repaired very easily most times ! when they stop building pressure all you have to do is remove the compressor head and replace the gasket there are 2 ,don't bother trying to buy a new gasket (you have to order them from china ) just go to the local parts store and buy some sheet gasket material and cut a new one .also if the pump has been laid down on it's side the oil will run into the pump cylinder and it will be hydro locked and have the same symptoms you describe leave it standing uprite and it will fix itself in a few days . I have one of these with a 21 gallon tank and have used it for years ,If you need parts or pictures I have a boxes full of parts for these compressors . I have never had to replace a capacitor and have repaired hundreds of these . I used to buy tractor trailer loads of store returns from harbor freight /home depot/ w w grainger /sears /kmart etc etc etc you can buy a trailer load 22-24 pallets of harbor freight store return tools for around $9,000.00 delivered on average they contain $40,000.00 worth of tools many in brand new condition ( a lot of people buy them take them home and use them and then return them saying they don't work ) harbor freight has a 30 day no questions return policy ! I have sold hundreds of generators that only needed gas and oil ! average profit from 1 of these trucks is $ 18,000.00 try doing that with any other investment in a weeks time ! You must be able to fix minor things with some like pull cords or clogged carbs ====easy money for the handy person !

 

[PalmSprings]

I spun the fan blade and the shaft moves freely, at he same time I pulled on switch of course, and it started to start,but tripped off.
So i guess its the capacitor that is bad, from what Ive gathered.

Oh btw,The capacitor says: CBB 60 125uF+/- 5% 2?0 Vac 50/60 Hz 17A 2.5hp 3400rpm
RE: 2?0. i cant read the middle number where I placed the ?

 

[RandyT]

Most likely the 2?0 is 240

 

[PalmSprings]

Oh I assumed it was just 110. Im guessing 220 or 240 is to start up and 110 is when it up and running.

 

[alchemysa]

I spun the fan blade, at he same time I pulled on switch of course, and it started to start,but tripped off.
So i guess its the capacitor that is bad, from what Ive gathered.

Oh btw,The capacitor says: CBB 60 125uF+/- 5% 2?0 Vac 50/60 Hz 17A 2.5hp 3400rpm
RE: 2?0. i cant read the middle number where I placed the ?

Dunno, but I'd suggest its not simply the capacitor. The capacitor just helps it to get started. If it started then tripped out it sounds like you have other problems too.

 

[Grumpy Old Man]

I spun the fan blade, at he same time I pulled on switch of course, and it started to start,but tripped off.
So i guess its the capacitor that is bad, from what Ive gathered.

Oh btw,The capacitor says: CBB 60 125uF+/- 5% 2?0 Vac 50/60 Hz 17A 2.5hp 3400rpm
RE: 2?0. i cant read the middle number where I placed the ?

I tried to tell you how to fix it ,it is not the capacitor these small compressors run hot and can seize easily take the fan off and work the shaft in both directions until it moves freely , You can not buy that capacitor with out ordering it from china even if it was the problem make sure it's full of 30 weight non detergent oil

 

[uglyboywith11fingers]

Oh I assumed it was just 110. Im guessing 220 or 240 is to start up and 110 is when it up and running.

the 220 or 240 is just the voltage rating of the capacitor. The motor voltage(110/120) will be on the motor plate.
If the motor spun freely, then I'd try a new cap.

Pete



Pete