1984 15hp: new thermostat and water pump, now water not making it up to powerhead

It had been 4 years since my last water pump replacement so I decided to do thermostat at the same time. The motor has worked fine for the last 5 years since I've had it, water has always come out quite strong from the pee hole. I have read pretty much all of Leeroy's rambling's during these past five years.
I hooked everything up same as last time: grommet is definitely in the copper tube, key is definitely in the impeller. After the first reassembly I hooked up mufflers, no water from pee hole. Took lower unit off and hooked up garden hose attachment to copper tube, now strong flow from pee hole. Reassembled, thinking maybe I messed up, same thing second time, no water from pee hole. Next I took water cover and thermostat out, hooked up mufflers, no water through water cover or pee hole. Disassembled, cleaned, reassembled 2 more times, just bcuz I thought I might have screwed up. Still no water from pee hole, or at thermostat. (also tried running with no thermostat, no difference).
I also hooked the lower unit up to the mufflers while it was separated from the motor and not much water came out the top of the water pump. Most of the water came out of the 2 drain holes on the lower unit, and also from the holes on the side of the water pump housing. I tried running it to see if that would help, but shut it off quickly so I didn't damage it.
I used to be able to get water from pee hole with mufflers on even without the motor running.
I have disassembled and reassembled this thing 5 times today, hoping to get out on the water, but I'm at my wits end. If I wasn't blad, I'd be pulling my hair out. The only thing I can think of is the kit is faulty (both water pump kit and thermostat are brp johnson parts from **********)
HELPPPPPP!!!!!!!!!

Re: 1984 15hp: new thermostat and water pump, now water not making it up to powerhead

Check the therostat to see if it has a bypass hole for the water to go thru to rest of the motor before it would open up. If there is not a bypass of some kind eather built into the motor or the stat then that is the problem. Water cannot get past the stat to fill the block water cavity and cause a overheat of the motor.
JMO Oldman570

Re: 1984 15hp: new thermostat and water pump, now water not making it up to powerhead

Not sure if there is a bypass in the t stat, but I ran it with no thermostat and still no water at the t stat or the pee hole.
Very frustrating considering it worked fine 3 days ago. I wish I hadn't thrown out the old water pump, cuz I'd put it back in, to see if the new kit is the problemo.

Re: 1984 15hp: new thermostat and water pump, now water not making it up to powerhead

There is a grommet at the top of the water tube that can collapse and cause flow problems. To get at it you will need to remove the power head though. It may well be your problem. What you have done so far is what I would suggest. You may pull the water jacket from the head with the garden hose connected to the tube but it sounds to me like the restriction is that upper grommet based on the comments you've made. Was your old impeller missing any vanes? Best of luck. Rick.

Re: 1984 15hp: new thermostat and water pump, now water not making it up to powerhead

It's difficult to completely follow what you have done but a couple of thoughts. Have you tried running water down the water pump when the lower unit is off. So putting the hose onto the lower pump grommet to see if water flows out the water intake area. It seems like you may have a restriction there since I think you said that when you put the garden hose on the bottom of the copper tube you got a lot of water out the pee hole but when you connected it on muffs you did not. A restriction between the water intake area and your water pump, in your lower unit, would cause this observation. Sometimes that water intake screen can get damaged or clogged. Be careful touching that screen, since it is very delicate and can damage easily.

Also, as Rick has said, sometime the upper grommet folds over. Perhaps when the garden hose was on the copper tube, it had enough pressure to push the folds back to allow some water to come out the pee hole, but again, when you have it on muffs using mostly the motors pumping pressure it is insufficient to overcome this restriction.

I would test my first thought first, since if the restriction is the upper water grommet, it will require the powerhead to be removed, to fix.

Re: 1984 15hp: new thermostat and water pump, now water not making it up to powerhead

so i had this problem with my 35 hp and what solve it was ............. check your stainless cup on your impeller and make sure that it is seatted correctly. I had this problem. NEw impeller, new cooling sleeve gaskets. and was about to tear down the entire powerhead. Then checked the impellor stainless cup for correct seatting.

I hope this help

Re: 1984 15hp: new thermostat and water pump, now water not making it up to powerhead

Those upper water tube grommets had a habit of swelling up on those mtrs.

Re: 1984 15hp: new thermostat and water pump, now water not making it up to powerhead

update
I put the boat in the water to test and it seems to be pumping water fine.
The main reason I thought it wasn't functioning is that before all this work, water would come out of the pee hole when hooked to the muffs, even without the motor running. After the work, water would not come out of the pee hole without motor running, and only a slow stream with the motor running on muffs. I also put the motor in a fairly shallow bucket(problem) and got no water from pee hole at all, which led me to believe something was wrong. Previously, the flow was very strong, even with the motor only idling. With the boat in the pond the flow is a slow stream at idle, but very strong stream when wide open throttle.
The motor also seemed to run much cooler before all this work, the water from the pee hole was almost always cool, very rarely was it even warm. Now the water is definitely warmer, but not hot. I'm thinking maybe the old thermostat was stuck open, and it has been running very cool ever since I'ce owned it.
Thanks for the replies. Hopefully its fixed, I was dreading having to remove the powerhead and miss more time on the water.

Re: 1984 15hp: new thermostat and water pump, now water not making it up to powerhead

I wouldn't be too concerned with the telltale water being a little warm - that's normal.

Misdiagnosis of cooling problems while using the muffs seems to be a pretty common situation. I much prefer to run motors in a trash can full of water. It's really not any more of a pain than using the muffs, and it's much easier to get the water pump to prime properly.

It's possible that if the impeller was running dry for some time that it could have heated up and become damaged, and so now its ability to pump water is compromised.

If it was my motor, I'd run it a while and give the cylinder head the "fingertip thermometer" test. If it's too hot to hold your fingertips against the cylinder head for more than 30 seconds or so, then it's too hot and your impeller may not be pumping well enough. If you can keep your fingertips there for a long time without any discomfort, I'd conclude that the water circulation is sufficient.