Pump intake grates- thinking of trying something taboo

[Spooling]

@swatski I know this is an old thread, but just looking at sealing my pump this spring. Was wondering how the JB Weld Marine has been holding up? Would you use it again if you had to do it again?

 

[swatski]

@swatski I know this is an old thread, but just looking at sealing my pump this spring. Was wondering how the JB Weld Marine has been holding up? Would you use it again if you had to do it again?

Next time I would use Bondo, polyester based - easier to work with and way easier to sand/smooth out as compared to epoxies.

But - I would not recommend honing the grates like I did, I’m now replacing both sides as they both show cracks, like I mentioned earlier for one:

I think there have been occasional reports of breaking those grates, not surprising.. In my case, I initially used the wrong tools and might have overheated the bars as I was trying to hone them, might have weakened them. I just noticed one of the bars in one of the grates missing, but don't have pics. I would think the worst case scenario would be sucking a bar in when those break - to that just freaked me out thinking of the carnage but fortunately did not happen. I am frequently plowing through some debris in the river. Those are only $50-60 a side, too. If there are some solid aftermarkets that are stronger and perform better, I would gladly switch.

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[Scottie]

@swatski do you think sealing the pumps made a significant difference? Is it worth the effort?

 

[2kwik4u]

@swatski do you think sealing the pumps made a significant difference? Is it worth the effort?

Was a noticeable difference on my AR190. I need to check my sealing again for this season, but it was easily as good of a mod as the L13 Cone was. And about 1/10th the price.

 

[swatski]

@swatski do you think sealing the pumps made a significant difference? Is it worth the effort?

100%

If there is any cavitation that would be the starting point for me, after checking the impeller is not damaged.

These boats should be able to come up on plane on one engine. If doing that kind of testing I would keep the “off” engine actually idling as to not swamp with water through the exhaust.

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[Spooling]

Thanks Swatski. I was also looking at another thread here, and Island Racing mentioned having good results using 3M 4200 fast cure. I'm trying to decide which way I'd like to go..

https://jetboaters.net/threads/jet-pump-blueprinting-how-its-done-by-wfo-performance.12127/post-209085

 

[swatski]

Thanks Swatski. I was also looking at another thread here, and Island Racing mentioned having good results using 3M 4200 fast cure. I'm trying to decide which way I'd like to go..

https://jetboaters.net/threads/jet-pump-blueprinting-how-its-done-by-wfo-performance.12127/post-209085

Good link. I was also looking at @WFO Performance work - I don't think he would say what they use but it's probably the best pump porting/blueprinting job I have ever seen:

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https://jetboaters.net/threads/jet-pump-blueprinting-how-its-done-by-wfo-performance.12127/

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[swatski]

Thanks Swatski. I was also looking at another thread here, and Island Racing mentioned having good results using 3M 4200 fast cure. I'm trying to decide which way I'd like to go..

https://jetboaters.net/threads/jet-pump-blueprinting-how-its-done-by-wfo-performance.12127/post-209085

I don't know what they do, but I consistently find even 5200 does not last more than a season, I can usually peel parts of it off. Not the MarineTex - that holds great. I'll be redoing my intakes and pumps this week, already pulled them off - will be using bondo (polyester).

As an aside - also replacing the intake grates, both were cracked/broken. Which is a bit strange as my impellers look absolutely pristine.

I would say, most likely sharpening/honing the grates weakens those considerably. I will not be doing it with the new set.

Out with the old:




And in with the new:



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[Speedling]

So @swatski you think removing middle web ok and maybe leave the knifing to a minimum would be the trick?
Just looking for some wrap up to this.
I won't remove mine because Lake Cumberland in spring has lots of half sunk tree parts that likely get pushed away from it but wondering what this mods best route would be.

 

[2kwik4u]

So @swatski you think removing middle web ok and maybe leave the knifing to a minimum would be the trick?
Just looking for some wrap up to this.
I won't remove mine because Lake Cumberland in spring has lots of half sunk tree parts that likely get pushed away from it but wondering what this mods best route would be.

Unsure what the size different is between the intake openings on the 24s vs the 19's, but my stock 2017 intake grate doesn't have the cross piece (I think what you are calling the web) in it. I've had a broken one already though, so perhaps the web would've been useful?

 

[swatski]

So @swatski you think removing middle web ok and maybe leave the knifing to a minimum would be the trick?
Just looking for some wrap up to this.
I won't remove mine because Lake Cumberland in spring has lots of half sunk tree parts that likely get pushed away from it but wondering what this mods best route would be.

IIRC I ran for two seasons with unmodified grades with no problems. One short season with modified grades, both are cracked or broken. That is not a definitive test, but indicative enough for me. I would not recommend this mod based on my experience. I do feel it helps loading the pumps somewhat but just not worth it, on balance.

Not a huge deal either, the grates are $62 a piece and easy to swap. I take those off every year anyway for an annual “pump physical“.

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[swatski]

@Speedling here are my impellers that I just pulled out over the weekend - they look pristine, no sign of any damage whatsoever. That tells me the grates must have been cracked by something that bounced off of them and obviously did not do any damage to the impellers, most likely some water-logged wood which plentiful in my river. That's lame!
Hopefully the unmolested OEM grates I'm putting back on will do better.
Port:

Strbd:


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[Spooling]

Anxiously looking forward to seeing how your pump sealing with bondo goes!

 

[2kwik4u]

Slightly off topic, but I'm curious if there is any data on surface finish of impeller vs performance characteristics.

@swatski any thoughts?

 

[Jgorm]

Slightly off topic, but I'm curious if there is any data on surface finish of impeller vs performance characteristics.

@swatski any thoughts?

I was just thinking, i wonder if polishing that would do anything. Probably not.

 

[Spooling]

I saw a post recently where GMtech spent a bunch of time polishing the prop to a mirror finish but he said it didn't make any difference in performance.

Here's the thread. It was actually on a GP1800 waverunner, but I'd assume the results may be similar?

https://jetboaters.net/threads/gp1800.19495/page-4#post-343506

Ah, it looks like he re-pitched it to, so this doesn't count... Nevermind, nothing to see here...

 

[swatski]

I was just thinking, i wonder if polishing that would do anything. Probably not.

Impros guys always claim that groovy finish is faster than mirror gloss.
I don’t think it really matters for us, at our level of performance.

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[swatski]

@swatski I know this is an old thread, but just looking at sealing my pump this spring. Was wondering how the JB Weld Marine has been holding up? Would you use it again if you had to do it again?

I forgot to update this, sorry!
(if I could quit my day job, please!)

So, I finally got to the pumps and intake over the weekend. I do this every year, used to use 5200 with okay results but it always comes off in big chunks at the end of the season. I can not believe how lousy the factory job is on those pumps - they all suck air from the bilge unless you seal everything.
Last year I tried the Marine Tex and it held up remarkably well. It is however not very easy to apply over larger surfaces or longer gaps, good for small jobs. It is also not the easiest resin to sand - epoxy hard.
Here is an example of a chunk of 5200 I applied last year that I managed to now pull out - so it is not holding very well:


Here is a gap left behind that chunk:


In other places it held for the most part but starting to come off on the edges:



Long story short, I removed all old caulking I could get out with various tools.
I went at it full animal.
This is my primary tool, and few other:



It was a beautiful day and was not rushing, took about half a day to prep/clean up and re-hone everything (next post).

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[swatski]

It is a dirty job. After few hours I had both pumps/transom rings prepped.
This is what I started with - not bad, yet, but time to clean up. Looking from the rear - with a pump pulled out:


Here is the same side after I was done cleaning it up - pretty much all the white stuff left is MarineTex from last year, all factory black crap and my 5200 is gone:



I decided to go with Bondo (poly resin) high bonding formula, it is excellent for this kind of jobs - bind really well and it is fairly convenient to apply (as far as those things go):


This is the can:


And the rest is... history, lol. Just freaking sanding. Hours of sanding.
I rely on simple tools, perhaps a flapper wheel would be better but my adapter took a dive so I used what I had, and a bunch of curved sanding blocks (or what fun):


This is the finished tunnel, I finished in 120 sand paper (I think):


Here is the other side (a look through the intake - with intake grates removed):


Not perfect but SO MUCH better. Hope this holds for more than a season!

I then just slapped new (unmodified) intake grates. Done.


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[jcyamaharider]

@swatski where did you get that bondo at? I looked on amazon and nothing. My boat is at SCBM and has been there for 4 or 5 months to get the jet pumps realigned. I am tired of not having my boat and I think I am going to do it myself. I think it is just the bottom plate needs to come off and re adjusted. I want to smooth everything out like you did after I do this.