Water intake Grate

[eddiet]

I have read in here a few times about replacing the stock grate with a 6 finger fixed gate but no one has listed where they are getting this from. Can someone direct me to a web site or a placeto order. This is for a 2000 Challenger 2000 with the Merc. Jet Drive. 240 EFI
Thanks

 

[biffdotorg]

I'm in the same boat! (slight pun) but I need one for a 240efi as well. I had seen a price once before and it was crazy expensive. Not as cheap as the PWC grates.

 

[Murph_13]

I've owned a 96 Challenger for 6 years and just bought my first Mercury powered Sea Doo last month (2002 Utopia), so I've been doing a little info searching on the Merc powered boats and I've read a lot about throwing the Hydro-Surge grate in the trash and replacing with a fixed grate.

I did a little looking (not much yet), but I found my best price on the 11-tine stainless steel grate (called the Rock Grate, P/N 854810T) at marinepartsplus.com...it was $194.76 to my door. I found it for $201.22 at boats.net to my door. So there are two places to start looking and if you find it cheaper, please let me know. A google search on the part number should pull up some places to buy from, sorry I don't have the part number for the 6-tine.

I've had a hard time deciding between the 6-tine and the 11-tine grate, but I think I'm going to go with the 11-tine.

Hope this helps.

 

[WAJetboating]

Time once again to repost some old data...

>>begin old post<<

I took some measurements of the aluminum and stainless steel grates just to see what is really going on. Here are the results. Lengths are not considered because all comparable lengths are essentially equal.

The unobstructed intake opening is approximately 7.188 inches wide. The aluminum grate's tines taper from 0.384 to 0.310 inches wide, yielding an average width of 0.347. With six such tines, the total obstructed width is thus 2.08 inches, or 29% of the unobstructed width. The stainless steel grate's tines are 0.235 wide for most of their length, and with 11 such tines the total obstructed width is 2.59 inches, or 36% of the unobstructed width.

While I strongly prefer the stainless steel grate due to its better-profiled tines (less turbulence) and increased strength (vs. aluminum), there is no question that the aluminum grate permits more potential flow - approximately 24% more than the stainless steel grate. Whether the rest of the pump system can take advantage of that increase to yield more performance is unknown (to me).

24% is enough of a difference that, as a wintertime project, I'm considering removing six of the 11 tines on my stainless steel grate. Starting with the outermost tines and removing every other one would leave five equally spaced tines with a total obstructed width of 1.175 inches, or just over 16% of the unobstructed area. The spacing between the tines would only be slightly larger than the aluminum's spacing, but much stronger due to the use of stainless steel. Best of all, this would represent a potential water volume increase of 31% over the standard stainless grate and 18% over the aluminum grate. A 20-30% increase in potential volume is definitely worth exploring.

I've heard of at least one SportJet owner that removed the two outermost tines from his stainless steel grate. The resulting 9 tine grate would have an obstructed width of 2.12, almost identical to the aluminum grate's 2.08 while retaining the stainless steel's substantial strength advantage. Such a modification is pretty simple to do with common tools since access to the outermost tines is very straightforward, so this might represent a good best-case compromise for we garage tinkerers [grin].

Here's a table of the effective intake widths. Percentages indicate how much of the original unobstructed width is still open.

7.188 (100%): No grate
5.108 (71%): Aluminum
4.598 (64%): Standard Stainless 11
5.073 (71%): Modified Stainless 9
6.013 (84%): Proposed Stainless 5

The 71% stainless figure is easy to achieve. But that 84% figure at the end is pretty tempting....

>>end old post<<

So tempting, in fact, that I did it back in 2005. Here is my 11 tine stainless intake grate with six tines removed via plasma cutter:

This works great. It's very subjective whether it had a noticeable effect on performance, but at least I have the peace of mind knowing that I'm not choking my jetdrive for water.

Hope this data helps!

 

[Murph_13]

WAJetboating,

Thanks for the great info. Nice job on your grate, I assume you ran it with the 11-tines prior to your modification. Did the 11-tines have a negative affect on performance vs. the Hydro-Surge OEM grate setup?

Thanks again for the info...

 

[Murph_13]

WAJetboating,

I think you've convinced me to go with the 11-tine, and I think I'll remove the outer two tines to start with and maybe duplicate your modification once I get used to the Merc powered boat...the 7-1/4" diameter pump vs. my old Rotax 4-1/2" diameter pump is obviously going to move a lot more water and I image the water vacuum it creates will take some getting used to? So maybe I better stick with more tines at first.

 

[WAJetboating]

Yes, I ran the 11 tine grate at first. I owned the grate before I owned the boat, having done the research on the incredibly stupid HydroSurge grate that has damaged countless jetdrives over the years. Once I owned the boat it never touched the water until I replaced the grate.

Obviously I didn't have any comparison between the 6 and 11 tine grates. I can say that the full 11 tines never caused us any problems nor gave us a reason to wonder. But after doing the math on the obstruction percentages, I just couldn't sleep until I achieved that 84% figure.

 

[WAJetboating]

I image the water vacuum it creates will take some getting used to? So maybe I better stick with more tines at first.

I don't think it will matter. "Getting used to" the boat won't be affected by your choice of grate. I'd say:

1) Get rid of the HydroSurge if you have it. ~$200 for a new grate is cheap one-time insurance for the ~$2000 in jetdrive damage that can result.

2) Pick your choice of the 6 or 11 tine fixed grate. My preference is for the stronger, narrower, better profiled 11 tines instead of the 6, but YMMV.

3) Modifying the 11 tine is entirely optional. It can always be done later, if at all.

Report back!

 

[Racereddie]

This ebay listing just expired but he had two Mervury aluminum intake grates (#852962T) for sale. You could contact him and see you can work a transaction out.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=220734870561&ssPageName=STRK:MEWAX:IT

Eddie

 

[Murph_13]

Thanks for the info guys...I will be putting the 11-tine grate on before I hit the water with it...the water's still frozen here (MI), so I have some time...I just got the boat and I've got a few things to do before the season starts.

Thanks again for the info...very helpful...

 

[biffdotorg]

That ebay auction is back up. I am unsure if it is against policy to post links to ebay auctions but: http://cgi.ebay.com/ebaymotors/MERC...at_Parts_Accessories_Gear&hash=item1e626c30d2


Ebay Item Number: 130500276434

Or just search for the mercury part number for the aluminum grate.

I made an offer of $50 and it was accepted. This is not the stainless 11-tine, but it is the aluminum 6-tine grate. This has got to be better than the hydrosurge grate.

Good luck everyone!

Mark

 

[WAJetboating]

This is not the stainless 11-tine, but it is the aluminum 6-tine grate. This has got to be better than the hydrosurge grate.

FWIW, in decreasing order of my personal preference, I would rank the various grate options thus:

Most preferable: Modified (5 or 9 tine) stainless
Next best: Unmodified (11 tine) stainless
Least preferable: Fixed 6 tine aluminum
Utterly unacceptable: Hydrosurge movable 6 tine aluminum

 

[biffdotorg]

FWIW, in decreasing order of my personal preference, I would rank the various grate options thus:

Most preferable: Modified (5 or 9 tine) stainless
Next best: Unmodified (11 tine) stainless
Least preferable: Fixed 6 tine aluminum
Utterly unacceptable: Hydrosurge movable 6 tine aluminum

That order makes sense to me.

The industry standard for PWC and jet boats has been cast aluminum grates. I am quite sure the stainless was introduced when people asked for a shallow water or "rock grate" as the stainless is labeled by mercury. To allow for as much water flow as the 6-tine, they had to make it with thinner tines and stainless steel for strength.

So for the average user that has not got the tools to modify the 11 tine, this 6 tine aluminum should be a good option to rid us of the Hydro-Surge. And at $66 shipped, that leaves me with $150 to put towards fuel this summer! (it will be needed)

All great input!

 

[WAJetboating]

So for the average user that has not got the tools to modify the 11 tine, this 6 tine aluminum should be a good option to rid us of the Hydro-Surge.

BTW, it cost me just under a hundred bucks to have a local machine shop plasma cut those six tines out of my 11 tine grate. If you buy a stainless steel grate today, you can always choose to later spend the ~$100 to go five tine. Totally up to you, just an idea.

 

[biffdotorg]

I just installed my new grate last night. That was a cake job! If anyone else is planning on doing this, don't be afraid as it is four screws and some thread-locker.

Keep in mind, I had to use a #30 Torx driver for two of the four and a 10mm socket for the other two. Those big Torx were a surprise. I was also surprised to see that BRP didn't put any silicone around the grate. There was some sort of rubber around the circumferance of the new grate though that compressed when I pressed in the grate.

This little bit of insurance is a comfort for sure! Anyone have a need for a HydroSurge and spring? (smile)

 

[Murph_13]

I installed the 11-tine SS grate two weekends ago and it is quite the easy job. I was surprised at how the Hydro-Surge has quite a bit of play before it even comes in contact with the spring. I imagine that just the water flow alone opens up the back end of the Hydro-Surge at least a few inches. I feel a lot better with the fixed grate and hope to get the boat out this weekend...finally getting some 70 degree weather around here...it's been unseasonably cool so far this year and I've only had the boat out once since buying it in February.

I'm guessing that you've had the same luck with weather up there in Minnesota biffdotorg...

I don't anticipate any loss of performance based on the great info that WAJetboating has provided...I do think that I may end up removing some of the tines down the road though...that eleven tine grate is a heavy chunk of SS!

 

[gerrvrell]

I have a 2000 Challenger 1800 210hp and I'm looking to replace the hydro-surge tines, but I'm having trouble finding an alternative that's discussed on this tread. I found on boats.net the factory replacement. Part# 856629T. Could anyone direct me to the 11 tine SS grate? Thanks!

 

[buckeye_paul]

The 12 tine SS grate is (854810T 1). Not cheap though.

 

[Racereddie]

I have a 2000 Challenger 1800 210hp and I'm looking to replace the hydro-surge tines, but I'm having trouble finding an alternative that's discussed on this tread. I found on boats.net the factory replacement. Part# 856629T. Could anyone direct me to the 11 tine SS grate? Thanks!

Here is a picture of my 11-Tine SS grate, P/N 854810-C (check the second picture), . I checked three places and that p/n won't come up, nor does it say that it has been superceeded, but since the 11 and 12 are both 854810 you can say that it has been replaced.

Eddie

 

[Strim]

Part number: 854810T1 is active and in stock at several Merc Distribution Centers / BTW, I've never seen a 12 tine Mercury Grate. Can someone post a pic?

 

[buckeye_paul]

I don't know if you're interested but a 6 tine aluminum grate is on eBay right now for $50. Search mercury grate.

 

[biffdotorg]

Unless you are in a really rocky area with small rocks, that $50 grate is a perfect option for these pumps. The SS grate is what Mercury/SeaDoo calls a Rock grate. Unless you want to spend the extra cash, the 6-tine is all you need.

Good luck!

 

[SeptemberC]

I live in WV. I don't think I have the need for the "rock grate" however I do need to replace my grate as I still have the spring loaded original.
We mainly run into twigs and the occasional Walmart bag lol.
Can you recommend a part number?
2000 Challenger 1800 with Merc 210

 

[buckeye_paul]

The 6 tine is: 856629T

 

[WAJetboating]

The 11 tine stainless steel "rock grate" is more efficient than the six tine aluminum fixed version. Years ago I did a careful analysis of the obstruction each presents to the incoming water flow and the 11 is the best choice of the OEM grates.