90TLRY Water flow out of pump housing

[ctbeacher]

Hi,

I have a 2000 (manufactured in 1999) 90 hp Yami model # 90TLRY. Last season I noticed the telltale stream started to get a little weak. This spring I ordered a water pump kit from Boats.net and rebuilt the pump. (Note, when disassembled, while the old impeller was a little brittle, it appeared to be whole).

During the rebuild, I noticed a thin layer of corrosion on the drive shaft where it comes out of the water pump housing. After struggling to get the old impeller over this section, I removed the corrosion with a strip of fine emory paper so I could slide the new impeller over the drive shaft. I did not go crazy here, just enough pressure with the paper to remove the corrosion.

After replacing the lower unit, I put muffs on the engine, turned on the hose and started her up. Water did come out of the telltale, but it is still a little weak. Also, there was quite a bit of water flowing out of the large hole in the lower unit where the shift shaft and speedo tube pass through. Because the telltale was still a little weak, I took note of this. To tell the truth, I can't remember if water came out of there before. My first thought was that I misaligned the water tube/water pump connection. So I pulled the lower unit and checked it. The tube appeared to be in the correct position and it had a coating of grease on it - that indicated that it did seat in the water pump grommet.

I took the lower unit over to a bench (still off the engine), connected the muffs, turned on the hose and watched what happened. Water came out of the top of the water pump around the shaft as well as out of the water pump outlet. This is probably where the water I saw exiting the gear/speedo hole was coming from.

I left the lower unit off and am trying to figure out what (if anything) is wrong.

Questions:
1) Is it normal for water to flow out of the top of the water pump housing when water is introduced under moderate pressure by a hose and muffs? I don't see any seals around the drive shaft in the schematics on Boats.net. The order of parts on the shaft is the impeller, the ss housing cup and the white plastic pump housing.

2) Looking at the Lower Casing Drive 3 schematic on Boats.net, I notice that there are two parts on the water tube that were not on my engine when I disassembled it:

List # 4 (90430-12072-00) Gasket, and
List # 1 (663-44367-00-00) Water Seal.

The only seals around the water tube where it enters the pump are a grommet (list # 15) that serews into the water pump and a water seal that sits in the water pump outlet under the grommet (list # 14).

Are these parts (list 4 and 1) indeed missing? If so, would they mean a major leak that would prevent a strong water flow to the head, causing the weak telltale stream and the water flowing out of the shift/speedo hole?


Assuming that the parts in question are not on my model, and that it is normal for water to flow out of the top of the water pump housing, my plan is next to make sure that the telltale hose is not partially plugged and to back flush the engine using the hose connection on the engine to see if water frelly flows down the water tube (to ensure that nothing is plugging the water tube).

Answers to my questions and any other suggestions would be most appreciated.

Thanks for your help!

[jonp]

Hi,

I have a 90 HP as well. Older though. I know what you are talking about. Mine does that as well, water exiting near the speedo. I assumed this to be normal. The water pump can only suck up so much. Have you thought about replacing thermostats? These will regulate water flow as they heat up. Also I am not sure about the Yamaha, but on my old V6 Merc I needed to install the impeller in a certain direction. And the old one did not look worn either, but still ran to the point of almost overheating until changed. They seem to get weak after 2 seasons. I will have the Yamie pump changed at the end of the season every other season by a mechanic.

Jon

[ctbeacher]

Thanks for the reply and suggestions, JonP. Once I am confident that I can replace my lower unit (after I find out about the phantom seals on the water tube) and get the lower unit back on, I will consider the themostat as a possible culprit.

As far as placing the impeller on the right way, the driveshaft has a metal key that only allows the impeller to go on one way. Then I followed the directions in the Secor manual to seat it in the cup by twisting the drive shaft clockwise as it goes in. That way the splines of the impeller sit correctly in the housing.

I'd appreciate it if someone can shed more light on my questions. Many thanks!

[ctbeacher]

Update on 90TLRY water pump

Update....

To play it safe, I ordered the two parts and installed them on the water tube. I really don't see how they can matter much, but I put em in anyway. Also replaced the thermostat.

Launched the boat for the season and the telltale now has a strong stream of water.

Now my problem is the prime start system appears to be clogged. Hard to start unless I turn on the prime start bypass.

Sheesh! Its always something, huh?

[ctbeacher]

Prime start fix

Update....

Finally fixed the primestart and subsequent bog down problem. See my post dated 8/16/07 titled "90TLRY Prime Start clog and Speed Bog Down" for details.

[FEA11111]

Hi,

I have a 2000 (manufactured in 1999) 90 hp Yami model # 90TLRY. Last season I noticed the telltale stream started to get a little weak. This spring I ordered a water pump kit from Boats.net and rebuilt the pump. (Note, when disassembled, while the old impeller was a little brittle, it appeared to be whole).

During the rebuild, I noticed a thin layer of corrosion on the drive shaft where it comes out of the water pump housing. After struggling to get the old impeller over this section, I removed the corrosion with a strip of fine emory paper so I could slide the new impeller over the drive shaft. I did not go crazy here, just enough pressure with the paper to remove the corrosion.

After replacing the lower unit, I put muffs on the engine, turned on the hose and started her up. Water did come out of the telltale, but it is still a little weak. Also, there was quite a bit of water flowing out of the large hole in the lower unit where the shift shaft and speedo tube pass through. Because the telltale was still a little weak, I took note of this. To tell the truth, I can't remember if water came out of there before. My first thought was that I misaligned the water tube/water pump connection. So I pulled the lower unit and checked it. The tube appeared to be in the correct position and it had a coating of grease on it - that indicated that it did seat in the water pump grommet.

I took the lower unit over to a bench (still off the engine), connected the muffs, turned on the hose and watched what happened. Water came out of the top of the water pump around the shaft as well as out of the water pump outlet. This is probably where the water I saw exiting the gear/speedo hole was coming from.

I left the lower unit off and am trying to figure out what (if anything) is wrong.

Questions:
1) Is it normal for water to flow out of the top of the water pump housing when water is introduced under moderate pressure by a hose and muffs? I don't see any seals around the drive shaft in the schematics on Boats.net. The order of parts on the shaft is the impeller, the ss housing cup and the white plastic pump housing.

2) Looking at the Lower Casing Drive 3 schematic on Boats.net, I notice that there are two parts on the water tube that were not on my engine when I disassembled it:

List # 4 (90430-12072-00) Gasket, and
List # 1 (663-44367-00-00) Water Seal.

The only seals around the water tube where it enters the pump are a grommet (list # 15) that serews into the water pump and a water seal that sits in the water pump outlet under the grommet (list # 14).

Are these parts (list 4 and 1) indeed missing? If so, would they mean a major leak that would prevent a strong water flow to the head, causing the weak telltale stream and the water flowing out of the shift/speedo hole?


Assuming that the parts in question are not on my model, and that it is normal for water to flow out of the top of the water pump housing, my plan is next to make sure that the telltale hose is not partially plugged and to back flush the engine using the hose connection on the engine to see if water frelly flows down the water tube (to ensure that nothing is plugging the water tube).

Answers to my questions and any other suggestions would be most appreciated.

Thanks for your help!

I am dealing with the same situation, no seals on water tube on removal, changed impeller, impeller cup, plate below impeller and the gasket, Impeller facing correctly, added seals on tube, and eyed in water tube to pump with the help of a friend. Flushed ports, changed thermostat and get same result , slow telltale for 4 minutes then starts tailing off then the alarm. While flushing ports pumped fine and heads very cool. I am baffled and confused as my local Yamaha dealer would not even sell me a housing for the top of the pump stating the water tube is not line up and I know it is. Any suggestions or pointers on how yours completed would be very helpful as I have been fighting this for weeks.