new water pump isnt pumping good!

[toddschubert]

Re: new water pump isnt pumping good!

If the impeller hub was spinning I think it would be a lot easier to turn flywheel or prop if in gear than with water pump working. that would tell if thats the case. You seem to know what your doing but you don't think your missing the tube when installing the new lu hugh?

 

[bob johnson]

Re: new water pump isnt pumping good!

If the impeller hub was spinning I think it would be a lot easier to turn flywheel or prop if in gear than with water pump working. that would tell if thats the case. You seem to know what your doing but you don't think your missing the tube when installing the new lu hugh?

no not missing the tube...its pretty easy to align , it engages one in the other while i can still see it!!! the only difficult thing about installing the lower unit prior to turning the bolts in, is the exhaust spacer -tube gets knocked out of place when you wiggle the LU to align the splines....twice i have taken those tubes out and found the gaskets crushed... thats not really a big deal....if it is sealed you keep a cleaner area around the outside of the water pump housing...( ie , no exhaust dirt or carbon).

bob

 

[clanton]

Re: new water pump isnt pumping good!

More photos with impeller out of the cup. Cup and plate do not look new, you said new. You said gearcase off, muffs on, water on, water did not flow thru to pump housing, sounds like water passage in gear case blocked. All waterpump housings for the V4/6s are not the same, one has bleed hole in the plastic housing.
Model number and OEM kit will get the correct housing, unless the gearcase has been changed to different style.

 

[Chris1956]

Re: new water pump isnt pumping good!

Bob, Did you follow the Service manual when rebuilding the waterpump? I worked on a lot of Merc waterpumps, but the Johnny Pump is a bit more complicated.

There is an oring glued into the plastic upper pump housing, between the ss cup and the plastic housing, one D-shaped one glued into the lip of the upper housing, plus several gaskets. You said you replaced everything, however, I agree that the wearplate does not look new, and I was concerned that you questioned the need for the upper pump housing to seal to the stainless wearplate. I think that is very important.

 

[bob johnson]

Re: new water pump isnt pumping good!

yeah this is the second kit I have installed on this style motor... the one on the take off was installed by me and worked perfect..i used the same manual as i did last time. factory for my model and year!the rebuilt LU is from a 97, and i was installing it on a 95, but they are the same... I bought the all inclusive kit.... the picture was taken after to took the rebuilt LU back off the motor to diagnose. so it was running for a totaly of 20 minutes anyway...

all parts were brand new. it is a possibility i left the o-ring out UNDER the ss cup...because i have not torn it down that far to look...yeah i was just [passing on ifo i realize was fast when I started the thread....the take off 2 years ago was pumping great...I was just being pre emptive prior to my seasonal use...and when i saw the gap I realized that i was getting great pressure even thouigh there was a gap....but i wetn ahead and sealed all around... i did NOT leave the gap on anything I INSTALLED!!

both LU cases are identical.... I actually have three of these motors!! I have a 1995 a 1996 and a 1997 115 hp ocean runners and ocean pros( ones an evinrude).

I stripped that case 100%...is there anything I could have forgot to reinstall that could make the pump suffer? looking at the exploded diagrams...doesnt show anything obvious.

bob

 

[1946Zephyr]

Re: new water pump isnt pumping good!

How is the water flow above the impeller housing? From what I can see, everything in the waterpump looks good. I just wonder if you may have an obstruction above somewhere.

 

[bob johnson]

Re: new water pump isnt pumping good!

How is the water flow above the impeller housing? From what I can see, everything in the waterpump looks good. I just wonder if you may have an obstruction above somewhere.

well the original LU was pumping water....and after I took it off and replaced and then removed the rebuilt unit...I stuck a garden hose up to the opening of the tube in the midsection...and water was squirting out of the tell tale like never before!!!! blasting a crater in the ground 10 feet away!!!! NO blockage there. Futher more I RE installed the original lower unit and it pumps fine....so the nothing in the motor is at issue....the issue resides in the rebuilt LU 100%.

right now i have the original LU back on and will use it that way...the way pump is fine,....I just thought it was time for a new one...since my head was running on the high side..

one of the things to address that was a new water pump I figured, and since I had the rebuild sitting there waiting...i used it.

bob

 

[1946Zephyr]

Re: new water pump isnt pumping good!

Very odd. Yea, it sounds like something may be blocked before the pump.

 

[Haffiman]

Re: new water pump isnt pumping good!

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

You seem to look more for limitations and excuses than solutions.
A decent sized garden basket with duc-taped plastic bags will hold the water and the gear case.
A solid rubber hose clamped on the drive-shaft, inside a socket that fits with a 1/4" extension, cut off the top and the shaft will fit in most power drills. A 1000W power drill should be able to pull that rpm as it will only have to pull the impeller, no prop !

 

[bob johnson]

Re: new water pump isnt pumping good!

just being a realist.....I took the water pump off and the O-ring sealed inside the plastic housing under the SS cup WAS there..and it was still sealed. I checked the brass insert-id piece of ther water pump and it looks fine... I put it all back together and went to the resivoir last night with my head lamp and two high torque 18 volt cordless drills. i took the D/S spline tool i made and a piece of steel turn down and with three flats to go into the 1/2 drill chuck...there are two speeds on each drill low rpm -high torque, gives 350 rpm...high speed low torque gives 1400 rpm...

the low torque setting sould not turn the shaft....all new seals, and pump!!! the high torque setting spun it full speed...350 rpm...and water gushed out the top of the water pump tube....but barely. the opening is about 7/8" ID and the water came out and rose maybe 1/2" at bst..if i put my thumb on it like the end of a garden hose, I could squirt the water 20 feet!! the tube in the mid case housing appears to be about 1/2-9/16th" ID...so there is some necking, but at 350 rpm i cant see HOW the water would go verticle 2 feet( the mid section height).

I didnt pull the ss plate under the water pump, because it would probably ruin the gasket under it that is stuck to teh LU housing..

when i got home i stuck the muffs on and repeated the test with the drill just for reference and piece of mind that the muffs should give me as much water as i need...and the water flow was identical to that of a fully submerged LU.


at this point Ill just give the LU to the mechanic, and let him install a whole new kit...maybe something it out of whack in the KIT.

thanks for following along and trying to help....

 

[Haffiman]

Re: new water pump isnt pumping good!

To me that test would indicate that the pump is working.
Between the pump and the pee-outlet, it should be 0 resistance.
How much pressure do you need on a hose connected to the water tube in the leg before water comes to the pee-hose nipple?
Remove the thermostats - how much pressure to get the water to the thermostats?
Are you sure that none of the thermostats are partly open or leaking giving 'no/low' back pressure?
Is the 'nozzle' in the pee-nipple still there?

 

[bob johnson]

Re: new water pump isnt pumping good!

sure it is WORKING, but very poorly, I THINK.
previously i described how i put the opening of the garden hose up against the end of the tube in the mid section and i got a fantastc spray from the tell tale!! my mechaic told me the garden hose would always have more pressure than the water pump could supply!! just think of a spray nozzle letting you spray the garden hose 50-60 feet across the yard!

the next good test would be to see the working LU and water pump under the drill expercise.

at this point I feel I have 100% ruled out any thing related to the motor from the LU and up...

the previous LU had a working water pump, I took off the whole LU.... and installed a different LU with a new water pump and the new one didnt work
I put the old one back on and it works.

the common denominator is all of the motor OTHER THAN the LU!!

every aspect of the motors water passags work with one LU but not the other... that kinda defacto points AWAY from anything in the motor as a cause!!


hope i described that well enough.

 

[Haffiman]

Re: new water pump isnt pumping good!

At the drill test, you said that when blocking the tube, water would squirt 20 Ft, this at 350 rpm only. The pump is working!
Why does not the pee nozzle pee 20 Ft?

Water must be leaking between pump out-let and water tube.

 

[toddschubert]

Re: new water pump isnt pumping good!

Future posters need to read whole thread huh Bob lol I think your description was good from the get go. You just have a weird problem.
Perhaps the jenny plate is inverted and the johnny hose cant fit. Then the left handed jam nut wont work! And BAM! no flow (or very little in your case)

 

[bob johnson]

Re: new water pump isnt pumping good!

I would agree that if the opening of the water pump housing does not fit closely around the od of the tube in the mid section...i could lose pressure..... I had greased that well you facilitate it sliding into place if i missed the aligment slightly. but as i installed the unit it was easy to see that aligmnet is easy to make on the model.

they have several different pieces that can get screwed ontop of the WP housing...because the kits fits several different models... i used the one that looked like the previous water pumps part.....

at this point Id have to remove the LU thats on there now to check what OD it is.


but i do have the 1997 motor totally apart...I guess i could go check the tube from that mid section...

the next test Ill dois add a tube onto the top pf the water pump outlet and make sure it is sealed tight..and make it al least 3 feet long......if the water pump can push a colum of water inside the tube out the top at 350 rpms....then it might be working right...... I am thinking it wont be able to do that.

i also may borrow a buddies HIGH power electric 1/2 drill....to try and get at least 1000 rpms.


bob

 

[toddschubert]

Re: new water pump isnt pumping good!

What about one impeller rubber being more flexible than the other. That could cause lower pressure.