Challenger won't go above 10mph - how to clear intake debris?

[anthonymsaad]

anthonymsaad just schooled anyone that thinks this will work! Should be permanently posted to this section.
Last night, I took my 08 Speedster 200 430hp out for it’s maiden voyage (my first boat). Made the mistake of warming up the engines at the dock on the dirty Delaware River here in Philly. They weren’t running for no more than 3 minutes before sucking up a big thick chunk of plastic (almost the top to a 5 gallon bucket) I tried the conventional OUTBOARD engine “trick” and it didn’t come close to working. If anything I just made it worse. Had to pull the boat out of the water, get it on the trailer and ultimately disassemble the rear drive. That process was relatively easy but a simple inspection of the water intake and the mechanics of it all clearly shows that the “tricks” mentioned above are only going to make the matter worse.

After clearing the drives this morning, I put it all back together and tried for round two of its maiden voyage. Very impressed with the power, the boat really hauls ass! Went about 1 mile downriver at 3/4 throttle, did some tight maneuvering before promptly sucking some twigs and a plastic bottle cap into the intake again!!! It’s always something!

So now I find myself joining this community because an amateur like me really needs a quick education. I haven’t ran this boat for more that 5 minutes at it’s full capabilities before getting myself jammed up again. Had to idle back a mile upriver and trailer it again.

I’ve purchased an “unclog kit” from Harbor Freight (pic attached) and hopefully I can fish this material out without disassembling again. This seems to be the legitimate “trick” for these boats. View attachment 35855

A few questions I have:
Are there intake grates that offer more protection? Basically, I don’t think I can run this boat in the Delaware River unless I can replace the grates with something that has tighter gaps.
Was I operating it wrong? I only did, 3-4 tight turns (not crazy turns).
I’ve attached another picture of my grate, does this grate appear to be stock or after performance type for max intake?
View attachment 35856

I called a few dealerships and nobody seems to service these boats or offer much advice. Can you all recommend an aftermarket grate that will offer better protection? I see PWC’s running this river in packs of 20 all the time. Are their intakes much smaller and have tighter grates with the ability to sift through foreign material better?

Sincerely,
Skipper Tom - Amateur Hour on the Delaware

Hey! Thanks for the appreciation! Im not too familiar in the factory intake grates, but I would say yours is more on the factory side, as it looks like mine. Moreover, performance grates generally have a bar that rungs perpendicular to those grates that helps redirect additional water up into your jet pump. With more water being forced in, more water can be forced out, along with a reduced load from pulling in water, which results in better performance.

Regarding getting an intake grate that is narrower and protect you against sucking in foreign objects, that would be tough. If you go too narrow, add more bars, you can restrict the flow of water into your jet pump, which will lower your performance. For me, I have similar concerns as you and trying to find an aftermarket performance intake grate, one that has a bar midway. It will help reduce the physical opening of objects that can pull through, but also improve performance.

If you can tell me more about your river, can try to offer some additional insight. I find it odd that you sucked something in twice so soon after leaving the dock. Do you know how deep the water is and, do you have a depth gauge on your boat?

 

[tcatmeow]

I double checked the depth charts and it’s plenty deep. Being a new body of water for me, I intentionally stayed within the shipping lanes. Which my charts say that it’s at least 25-40 feet.

The first jam up, which occurred at the dock before I even left was pretty damn bad. Pic attached. It was almost like a plastic belt or Rubbermaid type material. This I actually had to disassemble to yank out.


Yesterday after driving wide open (within the shipping lanes) for 1/4 mile, I back it down and started doing a few tight turns, stopped and then did a few more turns (basically trying to get a feel for how it maneuvers). I killed the engines to reorganize the deck and when I turned the engines back on. As soon as a gave it throttle I knew it was clogged again. That clog wasn’t bad at all really. I’m surprised it didn’t shake loose or process through the system.

The river isn’t weedy at all. It’s a little silty and rock far underneath. For example, you’d have to drag anchor for a good 30-50 yards, skipping over rocks before the anchor would catch.

Biggest issue I see with this body of water is just sticks, branches and plastic type material. I don’t understand all the jet ski traffic running this river and why a jet boat would have problems. I plan to take it out in the next few days and I’ll report back with how it goes.

In the meantime, I’m trying to research new grates with a little more protection and/or blades with more aggressive pitch. What do the wear rings do exactly?

 

[anthonymsaad]

That is really odd. If you're going fast, and on plane, the boat is nearly skimming the surface with the jet intake grates only a few inches below water. Because of that, it can allows for materials that float to get sucked in readily, as i would imagine. Definitely look at jet ski intake grates and see what they have, i would expect them to be relatively the same.

Getting a more aggressive pitch on your impeller wouldn't necessarily help much at all. Unless you plan on swapping out your SC for larger ones and all the work involved to increase power, I wouldn't mess with impeller pitch too much.

Wear rings are the rings that go around your impeller, helping to ensure you have a tight and minimal gap between the leading edge of your impeller blade and the ring itself. A tighter gap allows for optimal water propulsion. For additional information, the reason you see 2 numbers when looking at impeller pitches is because the blade is designed to suck in water and then push it outwards, in a centrifugal effect. Therefore, having the minimal gap between the impeller and the wear ring helps reduce water pushed out there slipping through and not forced out. Wear rings, as the name suggests, is designed to take the brunt of the damage and wear over time. Because jet boats and skis typically can handle shallower water, and have a higher potential of sucking in foreign material like sand, gravel, or whatever, when a they do get sucked in, they are carried along with the water. As i mentioned earlier about water being pushed outwards to the edge, so do the materials sucked in. In the case where you beached your boat and leaving, and had sand sucked in, that sand would essentially be forced in-between the wear ring and the impeller blade. In that situation, the weaker material, less able to resist that force, will end up taking more of the force and get damaged faster. If the wear ring were just a solid piece of metal, it's thickness could handle a lot, especially since material would be thrown directly on it and nothing there could be bent. On the other hand, you have a very thin blade that can bend and will receive the majority of the damage.

Essentially, when sucking something in, either the wear ring or the impeller needs to take the force, unless you can break the foreign material like cutting through seaweed. But since you can't really crush rocks or sand, something has to give. And when you're looking at a stationary metal tube and a high spinning impeller, with thin blades, the impeller will experience the most force and suffer the most damage. Sucking in a rock will most likely bend an impeller blade because it takes less force to do so than punch a hole through a metal tube. With sand, it will most likely chip the impeller blade.

Back to the point of a wear ring, in order to handle the inevitable situations of sucking in a foreign body, you need to account for the forces exerted inside the jet pump. With the impeller blades being the weakest part, you don't want to be constantly replacing a metal part that needs to be precisely CNC machines and withstand high RPMs for extended periods of time, and be a pain to remove and install. That would very annoying and expensive. Instead, you install a piece of material that lines the metal tubbing of the jet pump and made of something that is weaker than the blade. This way, when a foreign material is sucked in, this part will take the majority of the damage instead of the impeller. And when it's time to replace, just need to swap it out. Additionally, it's made of a weaker, less expensive material and the only precision involved in manufacturing is the diameter and surface evenness, which is drastically easier to do than the precision involved in an impeller. With all that said, that is why a wear ring is necessary and what it does, as well as why they are typically made of some form of plastic. It's still hard enough to function and handle most stuff, like sand and small rocks, with slight indentations and damage, and allow for the boat to continue performing relatively the same. But again, its still able to extend the life of your impeller.

If that doesn't make too much sense, I would say its similar to a case on your phone. If you drop your phone, without a case, yeah your phone could handle the drop, but it would suffer quite a bit of damaged as it would bend, if its metal, and the screen would crack due to transfer of forces. If you had a case on, usually plastic, it would be able to absorb the forces and reduce damage to your phone by breaking, cracking first or flex while leaving your phone intact. And when you compare a $20 case to a $200+ repair bill, id rather replace a phone case than my phone. It's cheaper to make a case than it is to CNC machine a metal frame of a phone and deal with all it's electronics. The wear ring is the equivalent to a phone case.

 

[tcatmeow]

So I’ll just chalk my experience up to bad luck. Took the boat out yesterday without issue. There seemed to be a slight difference in floating debris yesterday (less) so perhap the tide coming in helped. The last two times out, the tide had been going out and probably taking all the crap from up river with it. At least that’s what I’ll keep telling myself.

I emailed R&D Performance USA about fabricating custom intake grates with more protection. No word back yet

 

[anthonymsaad]

Glad to hear you didn't have another incident! That could be it. And again, keep in mind that when you do go faster, you're really skimming the surface of the water and it's a lot easier to pick up floating debris. In that sense, would driver slower to get the boat to sit deeper. At least that way, floating debris gets pushed around the boat, with the keel back in the water, and not getting debris under the boat and potentially sucked into the intake grates.

Definitely do let us, or me at least, know about the custom intake grates! Would love to get a pair as well! If they can't, may look and verify the dimensions and specs of an RXP intake grate and see if they line up with our boats. If anything, id go for a performance intake grate. Helps prevent larger debris from entering but if there's small debris, would probably force more in. Luckily, I don't have much debris in the lake near me.

 

[pvamax]

Unfortunately there is nothing to gain with intake grates on the boats. Back when i had my 215 sportster i was looking into performance upgrades and intake grates were on the list. What i found was that all the grates offered were made for skis and designed to keep water flowing into the pump and keep the ski from becoming unhooked in choppy conditions, something the skis need as they bounce around allot more than the boats. With the shape designed to bring in more water, that also brings in more trash that's in the water, something everyone with boats seems to have trouble with already.

 

[anthonymsaad]

That is definitely true for sure. For me, in the waters I go in, there are hardly any debris and a lot of waves and if grates can help hook the boat a bit more, I may swap mine out for that. If I do go into unfamiliar water, may look into swapping them out to stock one, but need to do some more research into how often I do it and if its safe to constantly be swapping out intake grates.