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-   -   502 mag mpi not priming oil?? (https://www.offshoreonly.com/forums/general-q/321395-502-mag-mpi-not-priming-oil.html)

502formula 12-24-2014 08:49 PM

Ok, I'll give those a try tommarrow when I get home! Thanks guys

sutphen 30 12-24-2014 08:51 PM

also,I've turned the priming tool by hand,just to make sure plumbing was right and oil would come out pretty easily from the line.when all hooked up,it will load a cordless drill pretty good.

Movie muscle 12-24-2014 09:03 PM


Originally Posted by 502formula (Post 4239802)
How much pressure should be on the shaft if you where spinning it by hand using the priming tool?

Not sure if you mean back pressure once the pump is primed or the amount of pressure you are pushing down on the shaft as you attempt to prime? I have addressed both below.

As mentioned in an above members post, drill speed can definitely be a factor, primed or not. Have seen guys spin away with battery powered or slower drills to no avail. Then pop on a good high speed hand power-drill and have it kick quickly.

As far as pressure on the shaft. You won't have to ask, you will know as soon as it catches oils and starts to build pressure. The drill will bog very noticeably. If you mean down pressure on the drill, a comfortable amount to steady it and keep it engaged in the slot but do not drive it home with a ton of force or body weight behind it.

I have heard from others that by overfilling the crankcase you can solve a dry pump issue but have not done this myself.

If you end up lacking success..... besides some of the possible issues mentioned above, there is the possibility of a dropped pick up?.....Can be verified with a little flex shaft inspection cam via drain plug vs. removing engine.

Good luck.

Black Baja 12-24-2014 09:18 PM

I have never had to prime a melling pump. I've never had to prime a motor more than a minute maybe two max. Try to turn the motor over and prime it. Do this a couple times if your then not getting oil something is seriously wrong. If you have the lines hooked up backwards the engine will still prime it's just not going to filter the oil the right way.

Quick2500 12-24-2014 09:44 PM


Originally Posted by Black Baja (Post 4239873)
I have never had to prime a melling pump. I've never had to prime a motor more than a minute maybe two max. Try to turn the motor over and prime it. Do this a couple times if your then not getting oil something is seriously wrong. If you have the lines hooked up backwards the engine will still prime it's just not going to filter the oil the right way.

Pull the plugs if you decide to do that to keep the load on the bearings as little as possible.

BUP 12-24-2014 09:44 PM

Pull out the oil sending unit and oil prime the motor thru that port with oil from an air operated unit or pump it with an heavy duty oil pump. Then I would make sure your oil level in the pan is correct and your oil filter is 100 % completely full of motor oil.

NOTE : Also make sure your oil filter is 100 % full as well if you continue with the drill / priming tool method. Take the oil filter off to check and fill it 100 % then see if that helps.

Next turn the motor over at the key switch with the spark plugs out and see if you get oil pressure at the gauge. While still cranking the motor over watch for oil moving in your valve train area.

For all 496's we oil prime thru the oil sending port with a CDI gear oil pump that is air actuated and of course its motor oil in the CDI gear oil pump not gear oil.

BUP 12-24-2014 10:07 PM

Here is the Melling vid - notice the drill size / speed and the priming tool used. Then watch for the oil priming for LS engines in vid as to what I mentioned to do at the oil sender port. . I talked to Melling about 4 years ago and asked do you really need to oil prime check the oil pump before installing it - they said yes for 2 reasons to make sure it pumps oil and it sure will help for oil priming the engine with the tool / drill method.

https://www.youtube.com/watch?v=tOYLlr8uQ8k

activator40 12-25-2014 02:42 AM

Sounds like the oil pump pickup fell out or is at the wrong angle..did you weld it into the pump??

502formula 12-25-2014 08:44 AM

How much oil should I put into the pan to sumerge the pump you guys think??

ezstriper 12-25-2014 08:44 AM

as mentioned before be sure oil lines are not crossed...did that once and would not prime, if still won't something is wrong, missing galley plug(s) had that happen before as well...you should see oil pressure on gauge within 30 seconds or so, never had to prime a oil pump either...good luck


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