3126 Priming Pump

dtfeld

dtfeld

Water Contrails
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Jun 5, 2016
5,571
Milton, GA
Boat Info
410 Sundancer
2001
12" Axiom and 9" Axiom+ MFD
Engines
Cat 3126 V-Drives
Priming Pump on my port engine is leaking. I did a quick look today and does'nt seem to be any items to tighten. Looking at the online parts, looks like a lots o-rings and such.

I've circled were I suspect the leak is coming from. Is this thing rebuild able??

Capture_LI.jpg
 
I would call Cat they can tell you. Also they would have the rebuild kit if they are available.
Just assumed it was the boat u have on your info.
 
Never had a Deisel boat , but have had several Cat and Cummins motors in Trks.
 
Your local Cat dealer should have a replacement pump. You will probably find it to be less expensive to simply replace the primer pump as a unit in the long run. Most of these type things have so much plastic in them that your better off with a replacement unit.
 
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I recall Frank talking about how those things can leak if the valve isn't indexed quite right. You may want to search around here a bit before ordering anything. Or maybe you already have checked that?
 
Replaced both of my priming pumps in June of 2017 after what seemed like forever to prime both engines after changing Racor filters. I was told by Michigan CAT they weren't rebuildable. Total price for the pump, seal, and gasket was about $275 for each engine.
 
I replaced one because it dripped a little when the other one started the same thing I wrapped it in a paper towel and put a wire tie around it. It gets changed once a year when I have to use the pump.
 
The Bill Collector said:
I replaced one because it dripped a little when the other one started the same thing I wrapped it in a paper towel and put a wire tie around it. It gets changed once a year when I have to use the pump.
Click to expand...

It’s dripping a little too much for just a towel.
 
David - If it's not leaking when the knob is locked and the selector valve is off then leave it and don't use it.
If you are still using the priming pump to get the engine started here is a better way -
  • Fill the racor after changing the filter as full as possible.
  • Set the throttle to wide open.
  • Crank the engine
  • Soon it will start to sputter then clean up and run normally; slowly back the throttle to idle as the engine comes up on the revs.
  • Done
 
ttmott said:
David - If it's not leaking when the knob is locked and the selector valve is off then leave it and don't use it.
If you are still using the priming pump to get the engine started here is a better way -
  • Fill the racor after changing the filter as full as possible.
  • Set the throttle to wide open.
  • Crank the engine
  • Soon it will start to sputter then clean up and run normally; slowly back the throttle to idle as the engine comes up on the revs.
  • Done
Click to expand...

I’ve had issues with this engines pump since I changed the filters a couple months ago. I looked at the pump yesterday and all seemed normal except it’s leaking. It’s not bad, but any fuel leak to me is unacceptable. I’ll take another look next time up, but I think this pump needs to be retired.

I do fill the racor, but the on engine filter is the one that I hate to fill during the filter change. I used the pump for that. PITA for sure, but I’d rather do a pump change than an injector or injector pump replacement.
 
dtfeld said:
I do fill the racor, but the on engine filter is the one that I hate to fill during the filter change. I used the pump for that. PITA for sure, but I’d rather do a pump change that an injector or injector pump replacement.
Click to expand...

You’re very wise. Filling the secondaries from a jug is a risk not worth taking. Unless your eyes are sharp enough to see particulates the size of talcum powder in the fuel source, you’re just dumping them in on the output (non-filtered) side of the filter, in which case why bother using the filter at all?
 
Last edited:
The final (secondary) CAT filters are 2 micron, not 10. I cannot find on the Mr. Funnel website where it indicates what spec it filters to. 2 micron? Doubt it.

Glad those of you that mention taking this risk haven’t had any issues. Yet.

Personally, I wouldn’t (and don’t) play the odds when manufacturers don’t recommend this and also provide you with priming pumps to safely fill the filters. I guess I don’t trust my $50k + engines to “Mr. Funnel.”
 
dtfeld said:
I’ve had issues with this engines pump since I changed the filters a couple months ago. I looked at the pump yesterday and all seemed normal except it’s leaking. It’s not bad, but any fuel leak to me is unacceptable. I’ll take another look next time up, but I think this pump needs to be retired.

I do fill the racor, but the on engine filter is the one that I hate to fill during the filter change. I used the pump for that. PITA for sure, but I’d rather do a pump change than an injector or injector pump replacement.
Click to expand...

I do the same things you do. Racor gets filled with fresh diesel and the secondary on the engine gets filled by using the hand pump. It takes a lot of pumps, but it works.
Dreading the day the hand pumps start to leak though.
Especially the starboard one.
 
I’m going to have to dig into a new pump, leaking pretty badly.

In looking at the filters, I think it you fill from the outer holes (as opposed to the center threaded hole) the fuel added should be filtered. Correct me if wrong. But if I can fill the filter almost full, that should cut down on future pump wear and tear.

Replacing the pump looks like a smelly stinky PITA. Better buy another big box of rubber gloves.
 
Check this place for the best price...
Hoover Truck Centers
973-347-4210
732-341-2128
856-773-4600
For your primer pump
 
dtfeld said:
In looking at the filters, I think it you fill from the outer holes (as opposed to the center threaded hole) the fuel added should be filtered. Correct me if wrong....
Click to expand...

You are correct. But, best of luck doing it that way without getting fuel everywhere, hence manufacturers putting the priming pumps on the engines for just this purpose.
 
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