Cooling questions for perkins 6.354

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Pack Mule

TF Site Team
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Location
USA
Vessel Name
Slo-Poke
Vessel Make
Jorgensen custom 44
I have a perkins 6.354 and have a few cooling questions.I cleaned my strainer and the bowl on the intake side and now I can actually see what's in there . Should there be any air bubbles in strainer bowl while running? For the manicooler would you use 7# cap or 14# cap ? Which impeller 8 vein or 12 ? It had an 8 with a spare so that's what I used .
 
I just did the same and am having a priming problem... I wil follow your thread as well! Hope I learn the CURE !

ps.. same engine...
 
I have a perkins 6.354 and have a few cooling questions.I cleaned my strainer and the bowl on the intake side and now I can actually see what's in there . Should there be any air bubbles in strainer bowl while running? For the manicooler would you use 7# cap or 14# cap ? Which impeller 8 vein or 12 ? It had an 8 with a spare so that's what I used .

You want the 12 blades

JABSCO -| Mfg # 1210-0001-P

Yes Bubbles are okay at first if you just cleaned the strainer. Tighten your sea chest cap on both side wing nuts.

Pretty sure my Manicooler is #7
 
I just did the same and am having a priming problem... I wil follow your thread as well! Hope I learn the CURE !

ps.. same engine...

Engines are self priming. With the sea chest cap off open the sea cock and let the water overflow then put the cap on.

Easy.
 
Engines are self priming. With the sea chest cap off open the sea cock and let the water overflow then put the cap on.

Easy.


I tried that, but it doesnt over flow...

So i added water too it with the valve off so it wouldnt run back into the ocean, and had my buddy start the engine then as soon as it was running I turned the water back on...
 
Barnacles love it in there. Could be sea grass and mud also. I'd take the sea chest/strainer off the valve hose and open the valve you should get sea water at a good rate coming up the hose.

When was it hauled last?
 
Thats what I thought, so I removed the supply hose, covered the barbed tip with my hand and blew thru the top access (dont make fun of me here) and I could EASILY blow the water out of the strainer and thru the thru hull and it quickly filled back up...

Plus I just had it out of the water last week and I cleaned out the sea life...
 
Mine has a 3/16" key drive and it is 2 9/16 " od x 2 " long and they key way goes all the way thru .
 
Thats what I thought, so I removed the supply hose, covered the barbed tip with my hand and blew thru the top access (dont make fun of me here) and I could EASILY blow the water out of the strainer and thru the thru hull and it quickly filled back up...

Plus I just had it out of the water last week and I cleaned out the sea life...

Priming problems. . . When's the last time you rebuilt your raw water pump?? Besides just replacing the impeller? If the rub block and backing plate are worn out, your pump won't have much lift.
 
If water won't overflow the strainer container with the thru hull open then you have an issue at the supply side before it even gets to the pump. Must be an obstruction of some type. Sea grass or a Jelly?
 
Priming problems. . . When's the last time you rebuilt your raw water pump?? Besides just replacing the impeller? If the rub block and backing plate are worn out, your pump won't have much lift.


But it was working when i pulled a couple weeks ago and once I replaced the impeller and put new thru valve in it and put it back it, it hasnt got water since.. seems like too much of a coincidence to me...
 
If water won't overflow the strainer container with the thru hull open then you have an issue at the supply side before it even gets to the pump. Must be an obstruction of some type. Sea grass or a Jelly?


I can see clearly thru the strainer and the water goes in and out easily, i removed the supply tube and covered the barbed end with my hand and I can easily blow the water in and out of the strainer and thru hull.
 
Thats what I thought, so I removed the supply hose, covered the barbed tip with my hand and blew thru the top access (dont make fun of me here) and I could EASILY blow the water out of the strainer and thru the thru hull and it quickly filled back up...

Plus I just had it out of the water last week and I cleaned out the sea life...

Is the point at which you are expecting the water to overflow out of the pipe (at the barb tip) below the waterline? Water won't overflow out of a pipe if it's above the waterline level, the surrounding sea level while you're sitting still.

ps. New impeller is stiffer, unworn, and will fit the inside of the pump body differently than the old impeller. Doesn't take much wear to cause the pump to not self prime when it's above the waterline. Did you lube the vanes of the new impeller when you installed it?
 
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But it was working when i pulled a couple weeks ago and once I replaced the impeller and put new thru valve in it and put it back it, it hasnt got water since.. seems like too much of a coincidence to me...

Ahh - I'm thinking the installation of your new thru hull valve has raised the position of your strainer. The top of the strainer is now above the water line, causing it not to fill completely with the top off. Now there is an air pocket making it more difficult for the r/w pump to prime itself.

If this is the case, you may have to refit your pipework to lower your strainer.
Also - Ensure the gasket on your strainer cap is sealing 100%. It may be sucking air in.
 
Is the point at which you are expecting the water to overflow out of the pipe (at the barb tip) below the waterline? Water won't overflow out of a pipe if it's above the waterline level, the surrounding sea level while you're sitting still.

ps. New impeller is stiffer, unworn, and will fit the inside of the pump body differently than the old impeller. Doesn't take much wear to cause the pump to not self prime when it's above the waterline. Did you lube the vanes of the new impeller when you installed it?


I did lube the veins with the grease that came with the impeller.

As for the hieght of the thru hull, its the same as when before except that I replaced the gate valve with a ball valve.
 
Perkins w/ Manicooler 7lb cap (4lb if you can find one)

Water will rise in your pipe only to the static WL so don't expect it to overflow if opening is above WL. It doesn't take much for a no-prime situation, just a pinhole to draw air will do it if your pump is worn. Refinish your pump cover, make sure you didn't push the key out when you installed the impeller, check all connections, gaskets. Some Perkins have the intercooler between the intake and the pump, if this is your case, and it has a leaking tube, it will never prime, just suck air thru the bad tube.
 
Bottom line: your pump doesn't have enough lift, either because of an air leak between pump and water inlet or the pump itself.

I think I read on your other post you started, that when you replaced the impeller you installed a thicker gasket between the pump body and the backing plate. That is a "NO. . NO" and will also cause the lack of suction you are experiencing.

The correct gasket is paper thin and ensures that the impeller and backing plate are at the correct clearance. Anything more and the pump will not work properly.
 
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I have the same engine. Top of the strainers are just above the waterline. I did manage to suck air once by tightening the cover unevenly. On another engine once I got air in through a hose that wasn't tight. Sometimes you can find an air leak by pressurizing the system with a garden hose.
 
I got all my questions answered and more . Superdiver I agree with Brooksie if you have the key drive like mine . I just replaced my impeller and I can see where it could be easy to push the key out of it's slot .
 
I have a keyed type that runs the length of the impeller. I didn't think the key could move. Where does it go? How do I put it back in place if it moves?
 
I put grease on my key so it would stay put in the key slot when installing the impeller . It helps if the key slot in the pump shaft is at 12:00 then the key will nest in it and no worries about falling out when pushing impeller in .
 
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