New Air Dog Motor and Now No Suction!!

T

tgibbs

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Mar 19, 2010
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First post over here, been watching some but hopefully you guys can help me out.

The original motor was popping fuses after I cleaned it all up so called Air Dog and they sold me a new motor. Installed it and went to start it last night and nothing. The motor is running but doesn't appear to actually be doing anything. I pulled the fuel inlet line off and hooked up a clear hose that was in a bucket of diesel and the fuel didnt even begin to climb up the hose. I checked the viton ball was in the right location, no blackages under the fitting in the side of the aluminum block, but the motor is running like normal. I checked that the rotor is spinning the correct direction and also played with the spring and viton ball on the return side. Everything appears normal so does anybody have any suggestions?

I talked with Air Dog a few times but the last time I left a message and nobody called back and they are closed for the day :nail: I would love to get this thing going tomorrow.

I wouldn't expect the pump to be bad as even a bad pump I would think would pull some fuel. I'm not a rotor expert but it seems if the motor is spinning it should be sucking something.
 
Loosen the fuel filter to allow air to escape. You could also fill the water sep with fuel. They are made to pump fuel, not air.
 
Have you tried pouring diesel down the outlet hose to help prime the pump?

Also, treed.
 
Water fuel sep is full of diesel and the filter was loosened and tightened. I have tried so many things I'm forgetting them all! But on a side note supposedly they are made to dry prime itself or at least that's what the instructions say . . .

I haven't tried putting fuel into the lines themselves. I will do that shortly.
 
With the pump running, pull the one at the cp3 for 2 seconds. Just off, and then back on, quickly. It will purge the air between the airdog and the cp3.
 
I was gonna say check the ball position since I had the exact same thing going on with a new one I got a while back, but you said you already checked that. Curious to see what it ends up being.

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The line at the cp3 has been cracked and attempted to purge air that way but no luck. I isolated it down to the pump as I tried a clear hose over the inlet and these was no suction on that tube. I also tried pulling the water fuel sep and checking for suction at the bottom of nipple that pulls fuel from the water fuel sep and there was nothing. Not even a hint of suction.

I feel I'm pretty sharp at diagnosis but I'm really kind of lost and everything leads back to the motor . . . Maybe I will take apart the old one and see if I can figure out what is shorting it out and drawing too much amperage thereby popping the fuse
 
Imelmo - I played with the ball position and it appears that it can only fit in one position. How was the ball in a different position than desired?
 
LReiff said:
Is the motor wired properly? Spinning the proper direction?
Click to expand...

This. Sounds insulting but sometimes they change things, and the terminals may be reversed. Other than that, as long as the motor spins at its rated speed, it's fine. Could be worn rotors or a suction leak somewhere.
 
tgibbs said:
Imelmo - I played with the ball position and it appears that it can only fit in one position. How was the ball in a different position than desired?
Click to expand...

On mine there was a cutout like a figure 8 and the ball had to be in one particular side. It could fit in either on mine. I can't remember off hand which side though.

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TheBigNasty said:
This. Sounds insulting but sometimes they change things, and the terminals may be reversed. Other than that, as long as the motor spins at its rated speed, it's fine. Could be worn rotors or a suction leak somewhere.
Click to expand...

I was thinking more along the lines of one slipping through production with the wire internally connected reverse of how they should be. Chit happens.
 
LReiff said:
I was thinking more along the lines of one slipping through production with the wire internally connected reverse of how they should be. Chit happens.
Click to expand...

Talked with josh at air dog and he said it should spin clockwise which it was. I am going to go check it again just cause but even if it were backwards then I would think I would have air being pushed out of the ports that I was checking for suction. Maybe not though.

I was playing the ball position and it seems to only fit one way on my particular pump but maybe I will pull it all apart again and verify this as well.
 
I think I have an old one laying around here somewhere. I'll take a pic and post what I'm talking about tomorrow if I find it.

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Well I think I figured it out. The shear pin holes drilled into the motor base weren't centered by approximately an 1/8". This kept the viton ball from fully seating thereby never giving me an suction :bang

I have some pictures I emailed to the Air Dog guys so hopefully they can confirm it. In the mean time I am playing around with my old motor, been thinking about putting it back together and running a larger fuse, previously it was blowing 20 amp fuses. Anyone think a 30 would work for now?

Thanks for the help all!
 
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