water pump impeller replacement

[jwilkey84]

Well, since I replaced the tstat on my 50 hp J50BELCTA, and am still having cooling problems I removed the lower unit and inspected the impellor again. I say it still looks pretty good, though ther is some minor visible cracking if you bend the flaps over pretty hard. But since I have it apart and the motor is new to me, I am going to take your guys' advice and get a new one. The problem was I was not getting water coming out of the pee hole. Well I looked at the depth of my water tank and the height of the lower unit water pump and I have come to the conclusion the the main problem may be that my water tank is not deep enough. With the lower unit sitting on the ground next to the water tank I have been using the very top of the tank is flush with the very top of the impeller. This makes me think that withe the motor runnig and with the waves being caused by the exhaust in the water, that there isn't enough water getting to the pump housing, thus not pumping much water up the tube. Does this sound like a good theory to anyone else? The impellor DOES have to be completely submerged at all times to pump water, right?
One more thing, I heard of a guy shooting water up the water tube with a garden hose and watching for water coming out of the pee hold to see if there was blockage there, is that a good test method. The reason I ask is that I did try that tonnight and no water came out the pee hole, it all just came back down the water tube, is that normal?

 

[1730V]

Re: water pump impeller replacement

Just because no water is coming out of the telltale, that does not mean it is not cooling. Telltales get clogeed all the time. The quickest way to clear them is with a straightened out paper clip. You can also remove the hose from both ends and blow through it. They usually clog at the fitting in the lower cowl.

Your water pick ups are below the cavitation plate.

 

[HighTrim]

Re: water pump impeller replacement

I believe it is a good idea to change that impeller. What that guy was probably referring to was running the garden hose , or a compressed air line, up the water line, where it slides into the impeller housing, to ensure that it exits at the t stat housing. This is done by removing the t stat, and running the water/air up the water line, to ensure it is not blocked. Also make sure the water intake area is clean of debris, and the tell tale nipple is not blocked with any spider webs or dirt. Use some water and weed eater line to clean it out, as well as the tell tale water line. And yes, make sure that the lu is fully submerged.

Typing at same time, sorry.

 

[jwilkey84]

Re: water pump impeller replacement

the tell tale hose is not clogged, as I have seen water come out of it before. The thing is that water does not come out until the motor has ran for 10-15 seconds and I usually have to rev it up just a little bit to get water to come out, and even then I don't beleive it is coming out like it should. So let me get one thing straight, does the impeller have to be completely submerged to work? I have taken the tell tale hose off and blew air through it so I don't beleive the hose has anyting to do with it. Do you think that it could be that my water tub just isn't deep enough? Nevertheless, I am still ordering a new impeller and owners manual tonight, I am just trying to figure out if I may need anything else before I place the order. By the way, thanks to all of you who actually reply to other's posts. It really helps and it is good to know that ther are still people who will take a few seconds of their time and knowledge to help someone else who wants to learn.

 

[1730V]

Re: water pump impeller replacement

The fact that you have to rev it up indicates a weak impeller. It does take a second, normally, for the block to fill up.

The only other problem area, in that system, is the thermostat. They are small and clog easily. The stat is located under the head COVER. You do NOT have to remove the head, just the cover.

 

[HighTrim]

Re: water pump impeller replacement

It sounds to me like your water pump/impeller needs attention. Check the water pump walls for scores or scratches, and if there are some, replace that as well as the impeller.

You type quick, but at least we're on the same page!

 

[jwilkey84]

Re: water pump impeller replacement

I know it takes a few seconds for the block to fill, but should it take 10-15 seconds? I did inspect the walls that the impellor brushes against and there is no wear at all on it. However there is a groove wore in the bottom plate, but I really hate to purchase the whole water pump repair kit; I would rather just replace the impeller. It's not that big of a groove and it certainly isn't going to wear clear through any time soon, so do you think I would be ok by just getting a new impeller? And if the new impeller doesn't fix things, what should I do next?

 

[1730V]

Re: water pump impeller replacement

That plate is the wear surface. Water can and will get by there.

Put an impeller in it and see if it works. If it doesn't, you know what your next step is.

 

[guy74]

Re: water pump impeller replacement

I would put in the whole pump kit if it were mine. I like doing it right the first time. My 2c

 

[jwilkey84]

Re: water pump impeller replacement

oK i got the new impeller installed, but I have one question. I read in my manual that I should spin the drive shaft as I am tightening the water pump housing to prevent the impeller gettig hung up on something. Well I was turning the drive shaft while tightening the screws and it became pretty hard to turn the shaft by hand. i have to grab the splines for some grip and then it is still kinda hard to turn by hand, is this normal? Maybe it fits tight since it is new.

 

[HighTrim]

Re: water pump impeller replacement

You should be spinning the driveshaft clockwise while lowering the impeller housing over the impeller. How hard are we talking? It is a little stiff, since the fins are new. A little oil on the fins of the impeller is good on a brand new impeller.

 

[jwilkey84]

Re: water pump impeller replacement

Yeah I did put some oil on the fins so I could get it into the housing easier. I just noticed that while tightening the housing screws that it got progressively harder to turn the driveshaft by hand. I think it is just because it is a new impeller, and I put a new wear plate in too, so that may be a tight fit. I'll fire it up this weekend and see how it works!

 

[jwilkey84]

Re: water pump impeller replacement

took the boat out yesterday, it ran fine but no water came out of the tell tale. I let it run till the alarm sounded, then brought it home. A friend and I took the motor off and tore the lower unit off again, frustrated. We shot water up the water tube and tried the weed eater string thing, and then we hooked up the aircompressor to the end of the tell tale hose and gave it some air, and wallah, a huge pile of leaves and stuff came crashing out. Hmmm, we thing we found the problem. Put it back together and we are off to the water again to try it out. I forgot that before I got this motor that it sat outside with the lower unit off, and some wasps or something must have got in the water tube. Why didn't I think of that earlier? I guess I didn't need a new thermostat or impeller afterall. Oh well, at least now that maintenenece is done, right?

 

[HighTrim]

Re: water pump impeller replacement

Good job, u gotta watch those pesky little critters! Blow the air both ways through the water line. Be sure though that if it is still not pumping water that you shut it down before the alarm goes off. When all is said and done, check compression and might want to take the torque wrench to all bolts on the motor, be sure to check your manual for the specs. Changing the impellor is never a waste of money. It will give you peace of mind.

 

[jwilkey84]

Re: water pump impeller replacement

took the boat out tonight with confidence. It started right up and begane to **** water pretty good, so we took it for a spin. I watched it carefully and it was peeing good and then after about three minutes of running I looked back and it wasn't peeing, so we headed it back to the dock. The alarm never sounded, so I guess that is good. But why did it quit pumping? Do you think there could have still been some stuff in there that has moved and is now blocking the passage again? If I understand correctly, the water should always be coming out of the tell tale, correct? should I remove lower unit and dusch it out again??

 

[HighTrim]

Re: water pump impeller replacement

very possible that is what happened. Make sure you flush it , and back flush it back and forth several times to ensure 100 percent cleanliness.

 

[jwilkey84]

Re: water pump impeller replacement

is it ever recommended to use anything other than water to clean out this system? Say like dranon or something of this nature? Just a thought.