new water pump isnt pumping good!

this is the second time i have done a water pump on this motor. the first time everything went well. and I was pumping at least 10 psi at idle and up past 25 psi at WOT.

lately the waterpump has been fluctuating...and never went past 15 at 3500 rpm...

so i had an extra lower unti i rebuilt sitting by and i installed that...I had put a brand new water pyump kit in it..well after installing it will only give me 5 psi at idle and maybe 7 at 2000 rpm....


what could i have likely messed up???

I am using rabbit ears to run the motor in the yard....does it not have a prime? the tell tale is OK...not strong like I like.....when running good the tell tale is a STRAIGHT line of water...now it archs down when in use at idle.

or did i justnot seal something???

is it possible i have ruined the impeller ...is there something i could reset if i took this unit off and removed the kit and re-install??

seemed so simple....and worked the first time .


bob

Re: new water pump isnt pumping good!

Hooked up to the muffs you are not even using your waterpump. The hose pressure is feeding the cooling circuit. Maybe that is all your hose can supply??

Maybe the grommet is pinched as well on the housing? What motor are we talking about here?

Re: new water pump isnt pumping good!

hey thanks...1995 60 degree looper ocean running 115 hp.

I have run the motor on muffs for three years now and have gotten 10 psi at idle, and have seen it run up when i reved it a little....now there is no response to reving...

everything seemed to go up easily...water is squirting out the tell tale!!! that means is coing through the motor...

but since I get no response when i rev...i think you maybe be right about the 5 psi is just hose pressure...maybe the key wasnt seated properly..and the impeller isnt turning at all.


I noticed once when i redid a water pump on a 15 hp four stroke last year that i had to stick the lower unit in a bucket of water to get the tell tale to peeee.

wondering if somehow...i am not primed....


bob

Re: new water pump isnt pumping good!

I think it is related to using the flush device. One question...when you first hook up the flusher, water is spraying out everywhere. Now when you start it, does it suck all the water in for a few seconds? it should. If it doesn't, I would question whether the plastic drive key is installed into the impeller correctly to lock in.

Re: new water pump isnt pumping good!

well, I would 99% rule out the flushing device....if it isnt a PRIMING issue...IE: the housing wasnt solid water to create a vacum to start pulling water...

it seems i used the first water pump install right in the yard on muffs.


i have been playing with this motor off and on for three weeks, dealing with a bad starter and a hot cylinder... and I have used the same muffs... and I always got noticable water pressure and i got water pressure response changes with rpm changes...

now with the new lower unit... i am not....so Id be looking somehwere other than the muffs for a solution...

probably the key...its a sliver of plastic that has to be held in with grease or it wont stay....maybe it DIDNT stay anyway.

bob

Re: new water pump isnt pumping good!

I just did my water pump and your right the key is a pain but you should be able to see if the key stays in place when lowering the impeller. The other prob as far as the pump goes could be oring around housing. that shouldn't affect pressure that much though.
Wouldnt hurt to redo water pump

Re: new water pump isnt pumping good!

Also a pinched water line along the way. I have done that before when raising up the gearcase by myself and didnt properly orientate the water line into the grommet. Check the water intake area for debris? Those are the only variables that could have changed that I can think of by simply installing a new gearcase.

Im not thinking the key is the issue, but maybe. Even without the impeller or key at all you would still get flow from the hose pressure feeding it.

Re: new water pump isnt pumping good!

toddschubert said:

I just did my water pump and your right the key is a pain but you should be able to see if the key stays in place when lowering the impeller. The other prob as far as the pump goes could be oring around housing. that shouldn't affect pressure that much though.
Wouldnt hurt to redo water pump

Click to expand...

the little things we learn along the way.... THINKING certain things are soooo important..case in point.

I twisted a prop shaft two years ago, thats why i rebuilt a lower unit and had the occassion to install a new water pump....

UP to that point of damage the water pump was pumping like a madhouse!! as much as 30 psi at times...and a STRONG stream at idle....when i took the lower unit off... and addressed starting to take the water pump housing off..... i noticed that i could see daylight under the housing all the way across!! the housing AND O-RING were NOT even touching the Stainless Steel plate they are supposed to make a seal with!!!!!!!!!!!!!!! I think the gap could have been up to 1/32nd of and inch!!!

soooo i thought then..SEALING cant be THAT important... but i tried to get a seal anyway and ended up applying sealant around the outside and under and all over the o-ring...

it worked only as good as the water pump with the gap all around under the housing!!!


so i doubt the o-ring could be the issue....

as with the previous water pump job...the one that isnt working now also got the sealant covering...

I think it has to be the impeller key....if the tube from the water pump housing didnt go into the right opening...i wouldnt even get the garden hose's PSI at the gauge!!!! theoretically i could NOT get any water pressure....how else could water get up into the motor...if one..the passage way was missed, or two, the pump is not pumping


hmmmmmm

no ones knows if it HAS TO BE PRIMED to start with?


bob

Re: new water pump isnt pumping good!

The pump is not self priming, that is why it must be submerged, beneath the water line, to function properly. Not an issue on muffs. Neither is a missing impeller key.

I still believe you have an issue with your cooling circuit. 2 seperate gearcases gave you issues, your problem is from the water line up.

Drop the gearcase and blast compressed air or the garden hose up the water line and ensure it is not restricted. Mud dauber nest in the tell tale?

Re: new water pump isnt pumping good!

My tell tail doesn't put out under (good) hose pressure only I've got the cross flow 90 (88spl) though. Can you rig a half drum or chest or something to submerge it?

Re: new water pump isnt pumping good!

I took the lower unit off...and i took the water pump housing off....this is what it looks like:



looks good to me.

this is the key. it was right where it belongs...



so i hooked the ears up to the lower unti while it sat on the ground...no water came up through the water pump housing tube....but water did come out of a side hole in the lower unit.

here is a picture of it:



when i hooked up the muffs to the lower unti I replaced...while on the ground..water didnt come out of the housing hole either...but no water came out of the little side hole in the lower unit case!!!!


could that be a clue?

after taking the lower unit off ands seeing the grease marks on the water pump hosuing tube ID, I can tell that the water tube in the lower unti case went inside where it belongs.


so i am dumbfounded...why this rebuilt unit wont pump water..

just came back in the house. tried sticking the garden hose up onto the tube in the mid section....it sealed pretty good and I got water coming out the tell tale under strong power! more power than when I had the lower unti on....
id bet the garden hose direct to the pressure guage would be at least 15-20 psi!!


so the passages must be clear...

the water just isnt making it through the water pump to the tube....

bob

Re: new water pump isnt pumping good!

Gee, Unscrew the water inlet gratings and see if the passage is clear?

Re: new water pump isnt pumping good!

Let it run on MUDs and watch the head temp w infrared thermometer. You could be having a normal thing going on. Head temp shouldn't exede around 150 deg

Re: new water pump isnt pumping good!

well took a LONG lunch in the rain today and did some tests. Checked the water pressure gauge hose...blew that out... reconnected and reinstalled the rebuilt LU. no change...very little pressure and temps running to 200 degrees in one head and 160 in the other. took the thermostat out of the hotter head and ran again. that head temp fell to 105 the other head ran at 170 ish and the tell tale barely spit( but i knew if have no pressure with an open T-stat hole! because i run with out t stats before)

tried another spare t stats and it got worse...but the old t stat back in and again temps ran to 200...

called my mechainc and talked a little... I pulled the hose of the water pressure fitting...and it didnt spray any water at all!!! the tell tale is spraying in a lazy arc to the ground only 4 feet away.

I said screwww this..and i pulled the LU and reinstalled the old LU...and sure enough the water pressure respoded...the tell tale spray 9-10 feet away and idle water pressure ran to 11 psi and would spike to 15 if i reved to 2000 rpms. both heads settled at 160 at idle... ran for 10 minutes.

previously when the head were runnign to 200 degrees i turned off the motor and quickly pulled the t-stats and sure enough they were open!


so now everything is running fine, with the exception that i thought I should be replacing my water pump, because even though it runs ok, it used to run a little more PSI last year!!

now to figure whats wrong with the water pump on the rebuilt LU.

in the end the starter replacement really helped, { i tried to address all the motor issues at once}.. the motor fires right off....and i backed the idle needles out one full turn...to hopefully alleviate the possible lean condition, that might have been running the one head hotter than the other...ill see this weekend if they both stay the same at WOT.

what could be wrong with the pump????

I have the o-ring on the SS plate...the gasket under the SS plate only goes one way!!!


hmmmmm


bob

Re: new water pump isnt pumping good!

did you replace the pump body as well as the impeller?..I ask because I had a 9.9 that had the hole in the stainless steel cup clogged with rubber and it wouldn't pump. I thought this might be an air bleed hole, but I don't know. It may have been merely coincidental. Anyway, with a new pump body it functioned normally.

Re: new water pump isnt pumping good!

AlTn said:

did you replace the pump body as well as the impeller?..I ask because I had a 9.9 that had the hole in the stainless steel cup clogged with rubber and it wouldn't pump. I thought this might be an air bleed hole, but I don't know. It may have been merely coincidental. Anyway, with a new pump body it functioned normally.

Click to expand...

yes i installed a complemetly new KIT...new housing.. new stainless steel plate, new stainless steel cup all the o rings and seals and gaskets..

and that lower unit housing was thoroughly cleaned and sand blasted and blown out and washed and dried and painted!!

bob

Re: new water pump isnt pumping good!

Assemble your pump, put the lower unit in a barrel/drum with water, put a 1 ft pipe in the water pump outlet, attach a pressure meter, spin the prop shaft with a power drill at 1000rpm - what is the pressure reading? Ought to be close to your 'normal' idle reading. If this works but not works when installed on engine, you probably has an exhaust leak into the pump.

Re: new water pump isnt pumping good!

Haffiman said:

Assemble your pump, put the lower unit in a barrel/drum with water, put a 1 ft pipe in the water pump outlet, attach a pressure meter, spin the prop shaft with a power drill at 1000rpm - what is the pressure reading? Ought to be close to your 'normal' idle reading. If this works but not works when installed on engine, you probably has an exhaust leak into the pump.

Click to expand...

that LU wont fit in a 30 gallon garbage can!!! and i have never seen a drill with a chuck that opens to more than 1"... I have an adapter that i machined at work, that i welded to a 1/2" drive socket that i used to attach to the drive shatf when i rebuilt the LU!! but I am not sure the drill I have has the torque to turn this newly rebuilt LU ast 1000 rpm!!


this isnt a little 6 hp outboard!!

bob

Re: new water pump isnt pumping good!

hmmmm...well my last dart at the dart board is this...from the diagram at marineengine.com it looks like there's an oring between the cup and the pump body where the d/s passes through...is it possible you left this out?

Re: new water pump isnt pumping good!

I am thinking it has to be something simple like that....it could be that because I have not take the impeller out of the SS cup . i took the housing off the D/S twice , examined the impeller, as it sat in the cup, which looks perfect still....checked for the o-ring on the SS plate..and the D/S key.....only other could be a close passge from the screen opening to the bottom of the pump.

I am wondering also if it could be a defect like the brass ring built into the ID of the impeller is spinning in place....the kicker is the pump, does pump some water.... just not near what it should be doing....which leads me to think a bad seal or gasket or....a missing o-ring...


bob