Sin Nombre

It's a '91 Johnson 15hp. I installed the complete kit and made sure the drive shaft was turning the impeller before re-installing. After installing the lower unit the engine starts right up, goes in and out of gear but no water from the indicator which had been working a few weeks ago. I had blown some air into the peehole while the lower unit was off and cleared the opening with weedwacker line. I put it in gear and reved it up a little but the engine is in a water filled trash can in the garage and overflows onto the garage floor when in gear so I can't do that too much. I could move outside if that would help.

When I turn the prop in gear it only turns as far either way that the impeller pin will allow it to turn against the flat on the shaft so the impeller must be turning. Any suggestions?

noelm

No idea what you mean about the turning the prop and the impeller pin stuff, but anyway, it was OK before so there's two options, you did something wrong when reassembling, or the pump is not the right one, there is no need for it to be in gear to pump water.

SaltyShepherd

Did you verify you put the impeller in the exact same way it was, with the fins pointing in the correct direction?

Sin Nombre

I installed the impeller the way the pros tend to do it, by installing the impeller and pin on the shaft first and then placing the pump over it, turning the pump in a counter-clockwise direction because the shaft turns in a clockwise direction. There is no way to verify that the fins are in the right direction because they are inside the pump at that point, and I have read multiple times that even if the vanes are in the wrong direction they will turn themselves in the right direction. Even if they continued to turn in the wrong direction it seems like they would still pump water.

Sin Nombre

The pin engaging the flat in the drive shaft tells me the impeller must be turning and pumping water. The Sierra pump kit was designated for the engine I have and all the parts fit perfectly. I know the engine does not have to be in gear for the pump to work but having it in gear before starting it can help condirm that the impeller is being engaged by the drive shaft.

I suspect the problem has more to do with the telltale stream which has been a problem in the past. If there was another way I could verify the pump was cooling the engine itself even if the telltale was not it would help to know what to be trying to fix.

Dacman

I always take lots of pictures before removal of things to ease the mind later if something doesn’t work .
You did something wrong cause it’s not working now..
Vanes righting themselves is not always the case. And they won’t pump if backwards.

Dacman

Take the telltale fitting out of the block and see if it pees then . I have a 15 Hp that a bunch of crud was behind the Npt fitting , blocking it.
Id do this before tearing stuff back down.

mbb

If you cleared it will weed eater line it should be clear. There's no magic there.

Not saying its the problem....but I recommend only using OEM impeller kits and install the whole kit the cup housing and impeller. OEM do not fall apart even after 20+ years. I've changed the OMC that was 23 years old, and a Yamaha that was 30 years old and both were in good shape. They had a set of course but they still worked and they were pliable.


But some people report some impellers dry rotting and falling apart and so in my experience, those must not be OEM ones...

I don't see how you can do anything but take it back apart and see if maybe you your impeller is not turning that the the woodruff key isn't in it or something

Corndog38

It is possible to slide lower unit into place and miss getting the water pipe to slide into pump outlet. Lower the LU and make sure the pipe pipe is in the right place. Another thing if old impeller came apart, water pipe could be clogged where it mounts under powerhead. Go ahead and drop LU and put a hose on water pipe and blow into it. Should blow pretty clear.

TTaxi

If the thin O-ring gasket slips slightly out of place during assembly , sufficient suction and pressure would not be achieved . And if the water tube lower or upper grommet is out of place (or the water tube is corroded through) , RW will not make it into the powerhead.
Double check the telltale will pass water.

With an IR temp gun or a temp crayon, you could check the powerhead temp near the t-stat which I think is likely to be a 143* spec. .

noelm

Having it in gear does not verify anything, the drive shaft turns when ever the engine turns, in gear or not, thus turning the impeller, buy a genuine kit, after market kits are hit and miss, ensure the water tube is connected to the pump, and the grommet is in place. Some of your terminology and thinking is vague at best.

Siwy

Any possibility that the remnants of old impeller ended up in the water passageways
just the thought

Sin Nombre

This morning I tried one more time to see if I could get the engine to pee. When I started the engine it would not pee and I didn't want to run the engine too long in case it was not being cooled but then in the early morning light I noticed a very faint mist coming out of the hole so I let it run longer. The mist got stronger and finaly turned into the strongest flow I have ever seen with this engine. I don't no why it took so long to get it to flow but I'm glad the problem is solved because I didn't know what else to do.
Thanks for the replies, everything helps.

Sin Nombre

Well I started it one more time and it will not pee lol. I put a compressor nozel over the hole and bubbles come out the water intake holes so I know the flow is not blocked and I know the pump is working because the flow was strong this morning. The engine is in a trashcan full of water in the garage so I can not rev up the engine which has to be in gear without sloshing water into the garage. I'm going to put the engine on a new boat Saturday and run the boat and motor in the water to see if that prompts it to pee.

noelm

OK, one more time, the engine does NOT need to be in gear to pump water, the drive shaft is mechanically connected to the crankshaft, the water pump is mechanically connected to the drive shaft, engine turns, impeller turns, even in neutral!

Hook Marine

Yep, that's got nothing to do with the problem. Putting the motor on a boat to run in gear isn't going to fix your issue. Drop the lower unit and take a peek at your previous work to make sure it's right. Is your intake somehow restricted by something in the trash can?

HookMeUpII

3 possibilities:

- You crushed the grommet on the top of the water pump housing that connects the water tube. Happens a lot since it's a PITA to align the lower unit back on
- Main seal that goes around drive shaft ontop of the pump housing is bad causing low water pressure into the head.
- You didn't align the key and the driveshaft is free-spinning on the impeller not actually pumping water.

Pull it back off and check those 3 things. I am betting it's one of them. Follow the instructions in the repair manual to the T.

Sin Nombre

So I called my mechanic in Maine and explained what was or was not going on. He was quite puzzled also after I assured him the drive shaft was turning the impeller, the water tube from the power head was in the pump grommet, the passage from the pump to the peehole was clear etc, and also that the engine had peed this morning and then stopped again, then started again, then stopped again. He suggested checking the thermostat for grit which I did. There were a few grains of large sand in the spring which I removed. The thermostat was hot so I know water was being pumped into it. I started the engine again and it immediately peed perfectly. Started it again and ditto. Tried again ten minutes later and it wouldn't pee.

I am convinced the pump is pumping water consistantly, not intermittently. I am going to assume for now that the water is reaching the power head. I am also convinced the passagway for the telltale is clear, at least while I am blowing air through it and when it is peeing properly. What I would like to understand is why the water exits the telltale intermittently. I get the impression this is not a common problem and may need an uncommon solution. No one has suggested putting a Flowmax in the gas tank yet, but seriously, any other thoughts?

noelm

Something is stuck in the water passages somewhere, maybe a piece of an old impeller that has been suggested a few times.

noelm

What is a "flowmax" and how is the gas tank related to water circulation? once again, your terminology and thinking is confusing.