Yanmar 3GM30F-YEU, raw water pump query

[jrevkin]

I did the raw water pump reorientation described by Joker460, to enhance the ability to get at the impeller for assessment/replacement.

http://forums.sbo.sailboatowners.com/showthread.php?t=148014

and added speed-seal life, and replaced the existing belt with a 3L180 belt. It's actually good that I replaced the belt, because examination revealed to tears in the previous belt.

I replaced the old tubing going from the raw water filter to the pump, and from the pump outflow to the heat exchanger, with 3/4" ID Shieldsflex, because I needed longer length hose> I re-routed the hose from the pump outflow to the heat exchanger, so it's now in front of, and not behind the V belts. I replaced the impeller and gasket, when I installed the Spead Seal life.

After connecting the new host to the pump intake and exhaust, and before tightening up the belts, I tried to manually rotate the pump, clockwise, hoping to prime it.

After starting up the engine there was only a dribble of fluid out the exhaust. I shut the engine off after 5 to 10 minutes, not wanting to overheat anything. The pump specs are
Johnson Pump F4B-903, 10-24509-01. Impeller Johnson 810B-1

Questions.

How long after starting the engine, should I see water coming out the exhaust.?
Could there be air in the hose between the raw water strainger and the raw water pump intake, causing an air block.
I prefilled the hose from the pump outflow to the heat exchanger to try to avoid an air block.
Any thoughts on next steps?

 

[Bill Roosa]

Not at all sure that rotating the housing and leaving leaving the hoses in the same (physical) location (the inlet hose is now on what was the old outlet port) will work. Impeller pumps have an inlet and outlet and rotating them 180 degrees does not change that unless you also reverse the direction of rotation. I'm not familiar with the re-orientation and old plumbing configuration so perhaps I'm not understanding fully.

 

[Bill Roosa]

NO, the impeller housing has a high spot inside the pump chamber that would get rotated with the housing rotation. The inlet is the inlet unless you move the high spot 180 also or reverse the rotation. Kinda like standing on your head rotates the housing also but the inlet is still the inlet (and) you don't have water flow and you changed the pump configuration.......... this is a no brainer. you did something incorrectly.

 

[Bill Roosa]

You can actually check if she is pumping backward as impeller pumps pump air pretty good. Start the engine and look over the side on the side the raw water intake is located. If you see bubbles then it is clearly pumping air from the exhaust to the intake thruhull. FWIW

 

[jrevkin]

not sure but i think you have the hoses on the wrong side of the pump intake and output barbs the motor turns in the clock wise direction looking at the front ...so the impeller also turns clock wise since you have reversed the pump which means that the heat ex changer hose should be on the top barb and raw water hose should be on the bottom barb some one correct me if i am wrong

Joker 460 pointed out that by reversing the pump, the old intake becomes the output and the old pump exhaust simply becomes the intake. He got the idea from the 3YM30.

Attached are pictures of the 3YM30 and how the rotation is supposed to work.

Do I need to prime the pump from the seacock side?

 

[Bill Roosa]

impeller pump 101. and I clearly do not understand what turning the pump "end for end AND rotating it 180" accomplishes.
there is a impeller that spins inside a circular housing. located to one side of this circular chamber are both the inlet and outlet ports. between the two ports is an insert that causes the pump vanes to bend. If you leave direction of rotation constant (think that is the case here) then if you rotate the housing 180 (axis of impeller rotation) the inlet port will be on the "other" side and you would have to re-plumb to move the inlet hose to the other side also.
I am completely confused by you terminology guys. What is the difference between "rotating the pump end for end" and rotating the housing 180 degrees"?

 

[Bill Roosa]

After taking a closer look at the pictures. if rotation is clockwise then the hose on top is the inlet. I can's see where the hoses go so I can't tell if its right or not.

 

[Bill Roosa]

thanks, I was wondering what rotating the housing 180 would actually accomplish, access to the pump wise. makes sense now. In any case the inlet is the top hose after looking at the pics

 

[jrevkin]

The purpose of moving the pump forward, is to enhance access for impeller replacement.

Jim

 

[joker460]

The orientation you have looks correct.
The top of the pump is the inlet and the bottom is the discharge.
Rotation is clockwise.
Water should flow in less than 30 seconds.

I think it may be a priming issue.

 

[woodster]

By the way I like what you are trying to accomplish in making better access to the impeller

 

[kloudie1]

My apologies!! I am the one looking backwards .. he said as he took a bite of crow..

If rotation is clockwise and pump and hoses are oriented as in the pictures attached to original post, intake is top hose and output is bottom blue stripe hose.. Looks correct.. No water flow is a result of an air leak or too much clearance around impeller sides or tips. Impeller should be carefully lubricated so that it primes itself. You can apply prime by loosening the hose on the intake side (which should be below waterline) and getting water to flow before putting it back on and tightening the clamps.

 

[jrevkin]

My apologies!! I am the one looking backwards .. he said as he took a bite of crow..

If rotation is clockwise and pump and hoses are oriented as in the pictures attached to original post, intake is top hose and output is bottom blue stripe hose.. Looks correct.. No water flow is a result of an air leak or too much clearance around impeller sides or tips. Impeller should be carefully lubricated so that it primes itself. You can apply prime by loosening the hose on the intake side (which should be below waterline) and getting water to flow before putting it back on and tightening the clamps.

This will be the next step. Thanks.
Jim

 

[badsanta]

After you figure out the right way. I would check the impeller. 10 minutes of pumping air should have ruined it.

 

[jrevkin]

After you figure out the right way. I would check the impeller. 10 minutes of pumping air should have ruined it.

will do

 

[woodster]

My apologies!! I am the one looking backwards .. he said as he took a bite of crow..

If rotation is clockwise and pump and hoses are oriented as in the pictures attached to original post, intake is top hose and output is bottom blue stripe hose.. Looks correct.. No water flow is a result of an air leak or too much clearance around impeller sides or tips. Impeller should be carefully lubricated so that it primes itself. You can apply prime by loosening the hose on the intake side (which should be below waterline) and getting water to flow before putting it back on and tightening the clamps.

OK after going down to the boat and getting my spare pump and bracket and marking the rotation on the normal set up and then flipping it over to have it like you have it and marking everything again it seems to me that i am incorrect in my assessment....it will indeed when flipped over not only change the rotation of the pump shaft it will also change the inlet and outlet ports as well so having said that disregard my persistence in the port location on the pump.......now Claude don't eat all that crow by your self as i have developed an appetite for the same bird....now to go delete the incorrect info from this thread

 

[kloudie1]

laughing, Woody.. I have a good Cajun recipe for it.. saute some onions and make a little dark roux... Bill, I owe ya a beer or maybe two. You were trying to get my orientation corrected!
Jim, Sorry for the confusion.. I hope you can get it going .. check that the cover is fully seating on the case so that there is no clearance between the impeller and the cover. Make sure the rubber is still connected to the hub.. there have been instances of the little hub being unglued from the rubber in brand new Yanmar impellers.

 

[petersea]

OK here is my suggestion.........follow the water flow....is the sea-cock open and water flowing...is there water in the strainer in and out ...water at the inlet side of the pump........ you get the idea some where you have a restriction or blockage that you need to trace down and eliminate.
You are working on the wrong side of the pump when you fill the hose from the heat exchanger to the pump you need to be checking that you have water flow to the pump. If you really are questioning the pump directional flow simply disconnect current hoses and reverse or test the pump with a 5 gallon bucket of water gravity flow to the inlet side. The answer to your original question is you should have exhaust water flow in less then 10 seconds even less as your muffler presumable already had water in it. As someone else has already suggested check the impeller as if you have run it dry most likely it is shot now. Another good suggestion about checking the impeller hub. If I remember correctly that pump should push 6 gallons a minute at 2500 rpm. If I am wrong someone will correct the pump spec I'm sure. Good Luck and keep us updated on what the fix was.

 

[Bill Roosa]

Did someone say beer? I always have to go through the mental picture of water flow with impeller pumps, every single time.

 

[woodster]

Did someone say beer?

yea i own you a couple two lol


I always have to go through the mental picture of water flow with impeller pumps, every single time.

i have to do that too but today my minds eye was suffering from acute dyslexia...or maybe CRS syndrome (cant remember s##t)

.