replaced impeller, now difficulty priming

[mikeneal]

I replaced the impeller on SBC Volvo Penta and now the crank mounted raw water pump is having issues priming off the garden hose with the new impeller. If I squeeze the ear muffs really tightly to the drive it primes and pumps water thru the motor and then is OK. Or if I attach hose to the "T" I have in the inlet side so I can flush boat while in the water . But if I shut motor off, remove muffs to allow the drive to drain and try to flush again it has hard time priming unless I squeeze the muffs by hand to the drive. I triple checked the hoses (inlet and outlet) are right orientation and they are. Any thoughts?
The pump has some scoring to the housing at the thrust surfaces and I am going to check the price of a complete pump. I don't think that is it though because I replaced impeller simply as maintenance deal and was fine prior to that.

 

[Bondo]

Re: replaced impeller, now difficulty priming

The pump has some scoring to the housing at the thrust surfaces

As you can see,......
ANY Scoring of the Pump's Surfaces is a Bad Thing......
Merc. uses some replaceable faces,..... With a Volvo,... I Donno.....

But,... I believe the Scoring IS your Problem........

 

[mikeneal]

Re: replaced impeller, now difficulty priming

Yea I agree, scoring (even on the thrust surfaces) is less than ideal. Stinks VP does not use stainless wear plates, the bronze wears quickly I bet and the pump is almost $300. :-(

 

[DHPMARINE]

Re: replaced impeller, now difficulty priming

I just hate when that happens.You were replacing the impeller because it should be replaced.Now it won't pump.Can we assume (I know) that it worked on the hose before?And nothing changed

Well something did,and i don't think it's scoring,but you also have to fix that.If we are talking 1999 5.0 the housing is less than $100.

The 'ears' or hose connection doesn't go bad usually.Sqeeze the 'ears' together before sliding onto the drive.

Then pull the 'feed' hose from the pump that goes to the motor.Run the motor.No water? time to back track.One time (and it wasn't at band camp) I had a new impeller with a spun hub.You never know.

DHP

 

[mikeneal]

Re: replaced impeller, now difficulty priming

DHPmarine,

I agree, I will pull it back apart tonight after work and lookie around the pump and impeller. My local VP dealer wants $280+ for the housing, can you expand on the location where i can get one for <$100?
I tried a second set of muffs I had laying around and same issue, if I squeeze them really tightly to the drive the pump primes.

 

[cobra 3.0]

Re: replaced impeller, now difficulty priming

On my OMC Cobra I had to change the the whole housing kit, not just the rubber impeller. GLM and Sierra may make aftemarket pieces for your drive and at more "affordable" prices.

 

[Gary H NC]

Re: replaced impeller, now difficulty priming

Check on ebasicpower.com
i have bought parts from them and they usually beat everyones prices.super fast shipping too..

 

[muc]

Re: replaced impeller, now difficulty priming

Sounds like you might have a problem with the o-ring or gasket on the front plate.
good luck muc

 

[mikeneal]

Re: replaced impeller, now difficulty priming

As I think about it today while I am at work. When I re-installed the new water pump it seemed like the pump housing rotated easier than it did in the past (I have to turn it to install the last of the 3 bolts holding it to the front of the crankshaft) . I am going to pull it back apart, I wonder if the impeller is too small of a diameter.
I have replaced it several times since I have owned the boat and I am 100% sure the part number is right but maybe the part was boxed incorrectly?

 

[Don S]

Re: replaced impeller, now difficulty priming

DHPmarine,

I agree, I will pull it back apart tonight after work and lookie around the pump and impeller. My local VP dealer wants $280+ for the housing, can you expand on the location where i can get one for <$100?
I tried a second set of muffs I had laying around and same issue, if I squeeze them really tightly to the drive the pump primes.

It might help in find a new pump if we knew what year and model engine you have.
Also, when you put an impeller in a pump housing, The impeller should set proud of the pump housing so it makes good contact with the cover.

 

[DHPMARINE]

Re: replaced impeller, now difficulty priming

I went to dougrussell.com and looked up parts for a 1999 5.0 Volvo.$88.19. I think I got 1999/5.0 from an earlier post of yours.

DHP

 

[Albe24]

Re: replaced impeller, now difficulty priming

My '97 5.7GSI also has a hard time priming on the muffs. Someone had posted awhile back that it was better to not run your supply water from hose wide open but am not sure why. On my set up the suction hose goes thru the transom then up and over bellhousing then back down to the raw water pump. I'm not sure why that is either, i think it would make it easier to prime if the hose was routed alot lower so the pump wouldn't have to overcome the extra "lift". How is everyone elses set up?

 

[mikeneal]

Re: replaced impeller, now difficulty priming

I am sorry, I thought I said that but I see I didn't, guess to know what I was asking about would help huh. . It is 1999 VP 5.0GL.

I installed the old impeller tonight (the flaps semed thicker at the root on the old impeller and therefore it seems stiffer. I think I can recall the other times I replaced the impeller the shaft /impeller tunned quite stiffly in the housing by hand. Now the pump spins almost free, way easier to turn then in the past (I think) . I havea factroy manulal and was hoping for abore diameter wear limit but didn't see anyhting. Anyhow, new verse old impeller, same effect though, difficulty priming. I see Doug Russel has the housing for 88 dollars. When I looked at housing closly I can see some wear around the thrust surface and the bore. I would have ordered a new housing tonight, but I also see some wear on the opposite side thrust surface . (on the body) So I wonder if I should just get a entire pump assembly. What really bothers me is that it seems worst now the before I messed with it.

 

[Don S]

Re: replaced impeller, now difficulty priming

Is that a 5.0GL-A,B,C, or D....... or ? ? ? ?
Do you have a flush hose on the forward, starboard side of the engine?

 

[mikeneal]

Re: replaced impeller, now difficulty priming

I am actaly not sure what letter I have after the 5.0GL, how do I tell? I do have a factory flush hose on starboard side. It is a factory "T from a a newer VP, I added that "T" about a year ago to semi flush the boat the coupe weekends a year we leave it in the water. The raw water pump works great if I use that option to flush and prime it first using that.

 

[Don S]

Re: replaced impeller, now difficulty priming

I may have gotten some years screwed up also. They are beginning to all run together, and so quickly anymore.
Anyway, look at this Volvo service bulletin for ID info.

Volvo Engine ID

Also, just above where the oil filter would be on the block on the port side of the engine should be a metal tag with the Model number, and the serial number. The Serial number would be best (for me) it's 10 numbers long and start with 4012. Like 4012XXXXXXX.

The other thing, is your flush hose. I have had a couple of engines that wouldn't prime easily because the cap on that flush hose was loose. If it's a little loose, it can suck air and make it hard to prime. Not a big deal when the boat is in the water, but with less water and more air when on the muffs, that little extra kind of kills it.

 

[mikeneal]

Re: replaced impeller, now difficulty priming

Don,
I thought of that too. (the flush "T" leak.) I double checked it all and I think it is air tight.

I will call my local VP dealer to see what they want for the pump. Since the pump has scoring on both thrust surfaces I suppose it is not going to last forever anyhow. I just hate throwing parts at something and the fact the issue arrived when I replaced impeller bugs me. (I am a "need to know root cause" kinda guy)

 

[DHPMARINE]

Re: replaced impeller, now difficulty priming

One thing (among others) that is previlant here.

The pump turns easily by hand.

A used impeller might.

A new impeller won't.

A housing cannot wear enough for the impeller to turn esy by hand.It would no longer be a housing.

Obviously and strongly I feel your new impeller is the wrong part.

DHP

 

[mikeneal]

Re: replaced impeller, now difficulty priming

DHP, I agreed with you until I took it back apart and compared the impellers. I say impellers because I have two new impellers and one old one. All three turn pretty darn easily by hand. I wish I could get a bore diameter of a new pump and see if the housing is that worn. The pumps are out of stock everywhere and they say VP will not have any until mid January at the earliest. :-(

 

[DHPMARINE]

Re: replaced impeller, now difficulty priming

Could that mean VP is having a pump problem? At anyrate,new impellers are difficult to get into housings and turn.


To be easy to turn,a housing wiuld have to be more than1/4 inch worn,oversize.That can't happen.It would no longer be a housing.

DHP