2001 Yamaha 90 hp 3cyl 2 stroke spitting water

[Rlilleaas]

What O ring are you referring to?

Difficult to say if any parts of the gasket was missing, it more or less broke to pieces when I pulled the powerhead and was then cracked in several places.

I will inspect the water tube more closely later today

[cpostis]

I am not overly confident that the gasket is causing the issues with the spitting water, the gasket surrounding the closed area where the "cooling pipe from the impeller" comes up looked relatively ok and thus should have sealed.

The water that came spitting out was colder than the water coming out from the control-flow out back, no water at all coming out together with the exhaust going to air.

Did you ever see signs of water inside the bottom cowling?
I think you should review the path of your cooling and exhaust systems.
A lot of this is conjecture, but I believe how my cooling system is piped/designed works.

Please look at the video of my motor (two stroke, SX150TXRZ). This vid is initial start up just after a rebuild but before replacing the water pump.
I'm not knowledgeable with your motor, but wonder if your motor is piped/designed so that excess cooling exhaust water is by-passed somehow goes to the front of your motor (mine goes to the rear). Don't know why Yamaha engineers will make this to come from the front though?

My motor will relieve minimal cooling water from these ports when run on muffs.

My motor, when on a tank (like in the video) back pressure from lower unit housing through the prop, and the resistance from the water exhaust port vents at the top of the lower unit, the water flow through the exhaust ports at the top of the mid section increase very significantly.

Just a few points you might want to consider. Maybe you don't have a problem after all?

https://www.facebook.com/chuck.posti...type=2&theater

Ill put an image together showing the areas I refer to and post.

[cpostis]

Did you ever see signs of water inside the bottom cowling?
I think you should review the path of your cooling and exhaust systems.
A lot of this is conjecture, but I believe how my cooling system is piped/designed works.

Please look at the video of my motor (two stroke, SX150TXRZ). This vid is initial start up just after a rebuild but before replacing the water pump.
I'm not knowledgeable with your motor, but wonder if your motor is piped/designed so that excess cooling exhaust water is by-passed somehow goes to the front of your motor (mine goes to the rear). Don't know why Yamaha engineers will make this to come from the front though?

My motor will relieve minimal cooling water from these ports when run on muffs.

My motor, when on a tank (like in the video) back pressure from lower unit housing through the prop, and the resistance from the water exhaust port vents at the top of the lower unit, the water flow through the exhaust ports at the top of the mid section increase very significantly.

Just a few points you might want to consider. Maybe you don't have a problem after all?

https://www.facebook.com/chuck.posti...type=2&theater

Ill put an image together showing the areas I refer to and post.

Look at the colored text, they correspond to the outline colors on the image.

Others, what do you think?

[cpostis]

You know what, maybe the leak is somewhere about parts 5-8 in the parts diagram Townsends sent. If this is the case, I think the mid section needs to be removed. That would include removing the mounts that often have the bolts seize from corrosion, and the bolt heads corrode as well. At least mine did.

2001 90TLRZ Yamaha Outboard UPPER CASING Diagram and Parts

[Rlilleaas]

Hi Chuck,

Thank you for your analytic reply.

I have had the motor for approx years, the water spitting has not been there before. Yamaha dealer had only seen this issue on 1 motor in the past (a 50hp). This have not been opened yet and is not in use.

The flood of water does not, as far as I would say, match the defects off the gasket. However by looking at it I do not see any other way. The part of the gasket surrounding the exhaust was in the poorest condition.

Your theory with the possible defects in the middle unit is interesting but it is hard to see that this can be the issue. The water was very cold, same temp as sea water I would say and I do not believe this had been through the powerhead prior to "departure".

Coolant pipe tested and found 100%ok

Still a mystery. Main theory is still the gasket between the powerhead and middle unit. We will know for sure on monday/tuesday next week when I will put the boat in the water again.

[TownsendsFJR1300]

*Coolant pipe tested and found 100%ok

Still a mystery. Main theory is still the gasket between the powerhead and middle unit. We will know for sure on monday/tuesday next week when I will put the boat in the water again.

*Yes, this is the pipe I was referring to. There's usually an 0-ring at the top end (lower end of pipe goes into the water pump).


Not that theirs 100 PSI of water being pumped to the power head but just a slightly worn damaged gasket will leak. Your pic's show major wear.

I do agree with Chuck thou, check everything while its opened up but my money is on that gasket and corrosion...


Chuck, here's a video of my engine on the muffs(not the best for looking at water flow, but I don't get any water coming from the front of the mid section.

http://s176.photobucket.com/user/SRT...ff81b.mp4.html



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[Rlilleaas]

Hi again,

I have already ordered the coned "seal/connection" connected by the two Philips screws on "water pump.jpg". However I do not think this is a required fix.

I am also replacing 2 off the 3 gaskets on the water pump (broke the gaskets myself..)

I am now doing a big NO when fault finding (changing out more parts than one at the time). However I am more interested in having no water splashing out from the front bit on Monday than knowing 100% for sure what caused the issue. My best guess is still the gasket, I cannot see any other way of water coming into the chamber (with the bottom seal for the crankshaft.).

Any water potentially being blown directly upwards from the wp (without going into the tube) would just cause a lack of cooling and go directly out in the same opening where the speed sensor is connected.

Still a mystery, and still my money on the gasket.

[Rlilleaas]

Video on the water prior to taking it apart

http://vid34.photobucket.com/albums/...ng%20water.mp4


I regret not investigating closer prior to taking the boat out of the water

[TownsendsFJR1300]

I find that video amazing with how much water the pump is pumping WITHOUT THE ENGINE OVERHEATING...

A tiny fault on that gasket (or most any other, loose clamps-automotive, etc) will allow a leak. That gasket was way OVER DUE for replacement.

As long as your inspecting everything else in that area and not finding anything, you should be good.

If you find some questionable pitting where the new gasket goes (I don't believe it REQUIRES gasket sealer), but Yamabond 4 works EXTREMELY well. It's basically used for main crankcase halves with NO GASKETS but works well with gaskets.

[Rlilleaas]

According to the Yamaha dealer these gaskets always looks a bit rubbish when taking the motor apart.

I immediately took the boat out of the water when I discovered the water spitting out there - thus I do not know if it would have overheated at WOT, however I assume so.

[pstephens46]

I find that video amazing with how much water the pump is pumping WITHOUT THE ENGINE OVERHEATING...

A tiny fault on that gasket (or most any other, loose clamps-automotive, etc) will allow a leak. That gasket was way OVER DUE for replacement.

As long as your inspecting everything else in that area and not finding anything, you should be good.

If you find some questionable pitting where the new gasket goes (I don't believe it REQUIRES gasket sealer), but Yamabond 4 works EXTREMELY well. It's basically used for main crankcase halves with NO GASKETS but works well with gaskets.

Is Yamabond4 an anaerobic sealer as Loctite 518?

[Rlilleaas]

I will use a loctite sealing for minor pittings

[TownsendsFJR1300]

Is Yamabond4 an anaerobic sealer as Loctite 518?

YamaBond 4 Semi Drying Liquid Gasket At Parker Yamaha.com


"Yamabond 4 Motorsports is a silicone based liquid gasket that fills gaps on a flange surface and prevents leaks. When cured, this product forms a rubber-like body that resists heat and seals joints subjected to high temperature. Gear and engine oil resistant, Yamabond 4 Motorsports sets in 60 minutes. Not for use on copper or copper-based alloys."



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[Rlilleaas]

Have been doing some more digging over the weekend, removed further exhaust parts / cooling pipe that potentially could give some more answers

- everything seems to be in a good condition. Cracked two of four bolts on the "closest" of the two larger parts in picture 4 while separating.

A good wisegrip tool helped getting out one of the studs, had to cut,drill and make new threads on the last one - took a while but managed a nice looking result. Cleaned up everything nicely and prepared for a new gasket to be installed.

New gasket and bolts to be ordered today, not planning on any more digging - assembly to follow.

[cpostis]

Any water potentially being blown directly upwards from the wp (without going into the tube) would just cause a lack of cooling and go directly out in the same opening where the speed sensor is connected.

Still a mystery, and still my money on the gasket.

Can't really tell from the pic (condition is questionable?), but be sure your damper seal and guide is in good/clean condition. I've ben made aware that these parts prevent exhaust gasses from going where they don't belong. Conjecture again, can a failure of these cause exhaust gasses to push cooling water where they don't belong?

These are items 10 and 11 in the attached link from SIM Yamaha.
Yamaha Parts Diagrams
FYI, Boats.net has the incorrect diagram and/or parts list in their website. I've chatted with them and they are to correct the discrepancies.