little giant 4-MDQX-SC troubleshooting

extreme5450 · 08/26/2008, 05:27 PM

I just aquired a little giant 4-MDQX-SC and it does not work. I was told that it had not been used for about 3 years and is a little rusty. When I turn it on I can tell that it is getting power but it just won't spin. Does anyone have any ideas of how I could get this pump working because it is a great pump and I would love to add it to my system. Any help would be appreciated.

Creetin · 08/26/2008, 05:40 PM

I never used these pumps. But i would check the bearings first. JMO

turbonut · 08/26/2008, 06:12 PM

yep most lil giant pumps require them to be oiled every 6 months the bearings are probly siezed

extreme5450 · 08/26/2008, 08:04 PM

I saw something about that but im not sure how to get to the bearing to oil

turbonut · 08/26/2008, 08:53 PM

Quote:

Originally posted by extreme5450
I saw something about that but im not sure how to get to the bearing to oil

if u look on the top of the motor u will see these lil cutouts and on the sticker it will say oil with an arrow pointing to each cutout use a dropper or a small syringe and use 20wt oil to lube however if the motor is already seized do to bearing failure then its already to late to oil and even if u were able to get the motor free it will only seize again

extreme5450 · 08/26/2008, 09:23 PM

can I get the oil at a auto parts store

Insainoreefer · 08/26/2008, 09:32 PM

My experience with the pump is that you have to remove the yellow plugs on the top of the pump on either end. Then use a light weight oil to lube with. The yellow cap on the top is there just as a protector to keep salt and dust out to ensure a longer life to the pump.

(BE CAREFUL WITH THIS NEXT STEP!!!!)
If the pump still won't run after the oil is applied, take off the fan cover (if it has one,.....some don't) and gently without bending the fan blades wiggle it to see if there is any play between the shaft and bearing. If there is and it's more than say 1/8", the bearing is bad and probably won't stay running long. Best just to buy another pump.

If not, then try plugging in the pump and start manually by spinning the fan blades, it should start at this point. Now add more oil to the oil ports and allow it to run for at least an hour. Unplug and allow it to cool. Once it is at room temp, plug it in again, it should start right away.

Never run this pump dry!!!!! It will ruin the shaft and/or impeller!

The key to this pump is the yellow plugs that cover the oil ports. If you take them out and blow into them, you'll see that it does not have a hole in them to allow oil through. Always remove them before oiling this pump.

I have some of these pumps running for 10+ years and still running strong! Though the 4-MDQX-SC is loud though!

3-MDQ
3-MDQX-SC
4-MDQ
4-MDQX-SC

extreme5450 · 08/27/2008, 04:05 PM

how do i get the fan cover off

extreme5450 · 08/27/2008, 07:46 PM

anybody?

turbonut · 08/27/2008, 09:16 PM

Quote:

Originally posted by extreme5450
how do i get the fan cover off

i dont believe they are removeable

extreme5450 · 08/27/2008, 10:10 PM

[QUOTE]Originally posted by Insainoreefer

(BE CAREFUL WITH THIS NEXT STEP!!!!)
If the pump still won't run after the oil is applied, take off the fan cover (if it has one,.....some don't) and gently without bending the fan blades wiggle it to see if there is any play between the shaft and bearing. If there is and it's more than say 1/8", the bearing is bad and probably won't stay running long. Best just to buy another pump.

how do i get to the fan then?

Insainoreefer · 08/27/2008, 11:07 PM

Quote:

Originally posted by extreme5450
how do i get to the fan then?

Does your pump look like the one below? If so, look at the instructions below. If not, post a pic of your model and we'll see what can be done.

Quote:

Originally posted by turbonut
i dont believe they are removeable

Actually it is.......

You should see a bell housing on the end opposite the pump intake. There you will find 2 or 3 screws, I don't remember, one on the bottom and 2 on the sides I think. Take them out and gently tap off the housing with a hammer. DO NOT BEND THE BELL HOUSING. Just light taps to set it free if its rusty. I usually will tap the foot that the pump stands on, then the opposite side, to walk it off. Be very careful not to bend the fan blades. If you do, it will cause the pump to become noisy and/or out of balance.

08/26/2008, 05:27 PM	#1
extreme5450 Registered Member Join Date: Aug 2008 Location: Midwest Posts: 388	little giant 4-MDQX-SC troubleshooting I just aquired a little giant 4-MDQX-SC and it does not work. I was told that it had not been used for about 3 years and is a little rusty. When I turn it on I can tell that it is getting power but it just won't spin. Does anyone have any ideas of how I could get this pump working because it is a great pump and I would love to add it to my system. Any help would be appreciated.

08/26/2008, 05:40 PM	#2
Creetin Limestone Cowboy. Join Date: Jan 2004 Location: In a little place i like to call a little place. Posts: 4,552	I never used these pumps. But i would check the bearings first. JMO __________________ If only common sense was common. Current Tank Info: 300 gal marineland deep

08/26/2008, 09:32 PM	#7
Insainoreefer Registered Member Join Date: Apr 2008 Location: Florida Posts: 96	My experience with the pump is that you have to remove the yellow plugs on the top of the pump on either end. Then use a light weight oil to lube with. The yellow cap on the top is there just as a protector to keep salt and dust out to ensure a longer life to the pump. (BE CAREFUL WITH THIS NEXT STEP!!!!) If the pump still won't run after the oil is applied, take off the fan cover (if it has one,.....some don't) and gently without bending the fan blades wiggle it to see if there is any play between the shaft and bearing. If there is and it's more than say 1/8", the bearing is bad and probably won't stay running long. Best just to buy another pump. If not, then try plugging in the pump and start manually by spinning the fan blades, it should start at this point. Now add more oil to the oil ports and allow it to run for at least an hour. Unplug and allow it to cool. Once it is at room temp, plug it in again, it should start right away. Never run this pump dry!!!!! It will ruin the shaft and/or impeller! The key to this pump is the yellow plugs that cover the oil ports. If you take them out and blow into them, you'll see that it does not have a hole in them to allow oil through. Always remove them before oiling this pump. I have some of these pumps running for 10+ years and still running strong! Though the 4-MDQX-SC is loud though! 3-MDQ 3-MDQX-SC 4-MDQ 4-MDQX-SC __________________ 210gal sps w/ 400wRadium20k on Galaxy Ballast , Closed loop run by a Dart to 1.5" x 2 through bottom, Blueline hd 20 running A.L. - Delta Star chiller on 2nd closed loop,LG4mdqx-sc main sump pump on custom fuge,E.T.S.S.1800xr

08/26/2008, 06:12 PM	#3
turbonut Moved On Join Date: Jul 2004 Location: moreno valley ca Posts: 578	yep most lil giant pumps require them to be oiled every 6 months the bearings are probly siezed

08/26/2008, 08:04 PM	#4
extreme5450 Registered Member Join Date: Aug 2008 Location: Midwest Posts: 388	I saw something about that but im not sure how to get to the bearing to oil

08/26/2008, 09:23 PM	#6
extreme5450 Registered Member Join Date: Aug 2008 Location: Midwest Posts: 388	can I get the oil at a auto parts store

08/27/2008, 04:05 PM	#8
extreme5450 Registered Member Join Date: Aug 2008 Location: Midwest Posts: 388	how do i get the fan cover off

08/27/2008, 07:46 PM	#9
extreme5450 Registered Member Join Date: Aug 2008 Location: Midwest Posts: 388	anybody?

08/27/2008, 10:10 PM	#11
extreme5450 Registered Member Join Date: Aug 2008 Location: Midwest Posts: 388	[QUOTE]Originally posted by Insainoreefer (BE CAREFUL WITH THIS NEXT STEP!!!!) If the pump still won't run after the oil is applied, take off the fan cover (if it has one,.....some don't) and gently without bending the fan blades wiggle it to see if there is any play between the shaft and bearing. If there is and it's more than say 1/8", the bearing is bad and probably won't stay running long. Best just to buy another pump. how do i get to the fan then?