Starboard Impeller no Grab

[Kalock]

Hey folks,
I really need this boat to get through one last season before changing it in for new.

I've had issues with the right drive for the three years I've owned the boat. It usually starts this way where you get ROM but almost no bite. Then "pop" it suddenly works and lasts all year. Next year, repeat.

Well this year there was no "pop". Just vroom no go.

The impeller and housing look great. There no debris in the channel.

I'm starting to worry there's an issue with the splines. Has anyone seen the drive out of the engine strip or would be be more likely the impeller shaft?

Any other thoughts are welcome.

 

[Bruce]

I would start by pulling the pump and having a look at the splines.

The video in this post will show you how https://jetboaters.net/threads/yamaha-jet-pump-disassembly-from-grant-browne-youtube.446/#post-4387

 

[Kalock]

I would start by pulling the pump and having a look at the splines. /QUOTE]

I assumed that was next steps and thank you for confirming. Looks like a good rainy weekend in Seattle project

 

[Bruce]

You can pull the pump in as little as 15 minutes. It is only two bolts for the control cables then four for the pump assembly. I used a large pry bar at the pry locations on the pump housing.

For reassembly you may want to find the service manual recommended grease and sealing products. I posted what I have used somewhere and can find them for you.

Take lots of pictures of the impeller, pump housing and spline so we can see what is going on.

 

[Bruce]

This is the post where I documented the chemicals I used for reassembly. https://jetboaters.net/threads/shaft-bearings-shot-now-stuck-shaft-ugh.157/page-7#post-31168

The directions on what to put where are earlier in that thread.

 

[Bruce]

@swatski, you are removing your pumps frequently. Are you installing silicone between the sections as you reinstall?

 

[Chillypilot]

I just reinstalled my pumps and used Yamabond semi drying liquid gasket between each section of the pump.

 

[Scottintexas]

what does ROM mean?

do you normally remove your cleanout plugs?

I agree with Bruce and also look underneath at your intake grate and sealant up into the intake just before the impeller to see if any is missing,

 

[Julian]

I'm guessing autocorrect changed REV to ROM?

Pulling the pump is easy....one steeling bolt, one spring loaded clip on the reverse gate (look at my reverse cable replacement mod to see how the spring clip works if you can't figure it out) and 4 bolts into the pump itself. Mine came off without much wiggling at all...some are more stubborn.

 

[Speedling]

@swatski, you are removing your pumps frequently. Are you installing silicone between the sections as you reinstall?

I have never used a sealer between pump parts!
Perhaps this is my next performance mod.
I will probably bring them to my father in law to sandblast them quick, then paint them in high heat paint, and then seal it all up!
Thanks again to all of you on the forums for making one of the most maintenance free boats out there into more and more mods and work, lol

 

[swatski]

@swatski, you are removing your pumps frequently. Are you installing silicone between the sections as you reinstall?

Sorry @Bruce just saw your message.
Those freaking St. Louis Blues... ehhh. (hockey stuff, you know; wife is depressed)
Anyway, the honest answer is yes and no. Usually no, because I do swap these parts A LOT... I have three venturi nozzles I'm testing for the best bore /opening size, I think I finally have it! But, when I think I'm going to leave it alone for awhile (I mean like.. two weeks or so..) then I do put a smidgen of 100% silicone (blue RV stuff is I think best for than) between the segments. Just enough to get a thin layer, nothing that would ooze out. I don't think it is super important but probably does not hurt.

 

[Kalock]

Heading over to pop it apart now.

Couple questions.

1. The sealing around the intake grate is definitely "worn" after 8 years of use. What do you guys use to reseal?

2. The dealer suggested a point of pulling air could also be the transom plate leaking. That's one that gives me the concern as that's a shimmed component subject to me messing it up on reinstall

3. Seal or no seal on rebuild? Seems to be up for debate

 

[Scottintexas]

is your sealant worn or missing? my 07 had silicone while other have a harder 4200/5200 material. if it's silicone give it a tug to see if it's loose, We don't usually see the transom plate be a air intake issue,

I'm more curious about the pop and then it works for the rest of the year, I'm wondering what dries out,

 

[Bruce]

3. Seal or no seal on rebuild? Seems to be up for debate

I used a thin coat of Life Calk between the pump sections. I was asking Swatski as he has the most experience assembling these things.

 

[Kalock]

I did find some wear on the prop. The rest looks "sealed". I may have to put it all back with new "gasket" material and see if that's it.

If that's not it then I'll pull the intake and reseal them.

So what's the going cost for a new shaft/impeller assembly?

 

[Bruce]

I believe that is cavitation wear on the impeller.

How do the shaft splines look? The impeller and shaft are separate pieces.

 

[Scottintexas]

The dings on the edge could cause problems but we've definitely seen worse that haven't caused your issues. The circled area is definitely a sign of cavitation.

How does the lower area of intake look, if you were looking up from the bottom?

I agree with Bruce to confirm how your splines are, the pop and then working fine the rest of the year has me confused, that's not a impeller/cavitation issue but splines or loose silicone could be,

 

[Kalock]

Yea the wear spot is definitely a cavitation wear. I'm more than familiar with that kind of wear. Reminds me of a plane prop after a dust storm

The splines looked perfect. No wear or markings at all. I need the boat moved back on the rack tomorrow to see the intake seal. For now I'm stocking up on 4200.

The reason I mentioned prop and shaft is I've seen too many people who found their bearings seized to the shaft. So I was looking worst case.

 

[ToddW850]

So the pic of the impeller showing where the area of wear is (circled). What could be a cause of that? Never seen wear on an impeller in a spot like that.

 

[Port0222]

I have taken my Props out, but I am not as familiar with what is on the inside as I spent less time studying that. see photo below -- What is that? Also -- Cavitation does not seem to be the issue described above -- what would "POP" and then not have cavitation all year. My impellers were WAY worse when I bought my boat but it would still climb through the RPMs and cavitate around 8000 rpm :https://jetboaters.net/threads/pulling-my-jet-pumps-any-advice.5831/

The Pop is what I do not get. That moment where it rights itself and stays that way for the season. Makes me feel like something is binding?... although -- I am assuming if you are getting RPMs -- The impeller has to be spinning -- was the impeller tight on the shaft? IDK -- Just brainstorming.