Random Engine/Cavitation Issues 2005 Challenger 180

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Hello all, I bought my first boat last week. My family and I are excited, but almost immediately we ran into issues. I’ve read through a bunch of the forums here and elsewhere and have tried out several things, but I continue to run into issues. Thank you to anyone who can provide any help or insight into these.
I have the 2005 Challenger 180 215hp Supercharged

1. Lacking thrust out of the hole - if I punch it, it almost stalls after a few seconds and then the supercharger kicks in. It is tough to get a slalom skier up behind and will take some practice. I’ve read that if I am trying to have an adult ski behind it, I may need to start it into a turn to keep water in the intake.
So far, we’ve replaced the impeller and wear ring with an oem impeller. The last impeller looked like it was in good condition, but the wear ring was etched quite a bit. We also found water in the jet nozzle and the bearings need to be replaced. I didn’t have the parts for that unexpected problem, but will fix when we pull it out next.
We also added thrust vectors from JetBoat Pilot. They had great customer service and I appreciate their how to install videos. The vectors help A TON with controlling low speed movement, but also may have introduced a bit of a rooster tail to the wake.

2. The cooling system housing that holds the thermostat literally pushed the thermostat out along with the hose while we were skiing. The engine coolant dumped into the bottom of the boat and the engine overheated and shut off. We soaked it up out of the hold and disposed of it without contaminating the lake. We swam it back to shore and had a friend pull us back in at very low speed since we didn’t have a clamp onboard for the hose that the manual suggests for when you are towed.
My friend and I patched it up and have a replacement housing ordered that we can install at the end of the season as there is a small crack in the plastic where the hose connector goes in. We filled it with distilled water to test out the system and it appears to hold as expected with a clamp around the housing. We took it out to test it and the engine was dry.
We pulled the boat out a few days later and when we undid the drain plugs, hot hot water came out. Not a ton, maybe a few cups worth. But it had me concerned with the coolant system. Everything there is still tight and we didn’t lose water from the system as the reservoir is roughly the same as before. We haven’t replaced the coolant and still have distilled water as we didn’t want to have another hose blow out and potentially dump coolant.
Yesterday is when I replaced the impeller and the wear ring and then we dropped the boat back in and drove it back to the dock. I rode it back at 6500 rpms where it seems to do best and it was fine, but again there was water in the bilge and it was warm. We grabbed a few more folks and took her back out. She doesn’t like to ride fully loaded. When throttling up she would do ok until we hit about 6700rpms, then she would spike all the way past 8000 and not give us any more power. We took her back to the dock.
I am excited about the boat and the opportunity to spend more time with my family, but frustrated right now. Can anyone help provide insight into what might be going on?
What do you mean "it almost stalls after a few seconds and then the supercharger kicks in"? If you are experiencing cavitation, then the RPMs would hit up against the limiter (8000 RPM) without the boat accelerating, not low RPMs like I and reading from what you wrote. Can you clarify?

If you get any water in the bilge from whatever source, you should expect it to come out the drain plugs hot. Water in the bilge sits pretty much right under the engine and will get hot. The entire engine compartment gets hot. So I wouldn't take that as a problem, in my opinion.

Why do you have water in the bilge at all may be a worthwhile question though. I can take my 180 out for a full day without a drop draining from the plugs at the end of the day. An open loop cooling system leak from exhaust or intercooler plumbing? Taking water over the bow that is getting into the ski locker or gas tank access hatch? Or a bad carbon seal which I would think could both leak water into the boat, and air into the impeller (causing cavitation), under different conditions?

I don't think it's a good idea to run the cooling system with only water in it, especially distilled water. It can cause rapid internal corrosion. Better to run it on the proper mix of antifreeze and water and if you loose coolant, pull the boat on a trailer and drain it out through the plugs. Running it for a short time while you are making sure there are no leaks might be one thing, but it sounds like you have left it and continued to run that way.
How many people in the boat and are they balanced can also make a difference for cavitation. Take out a few times and just get the feel of her. If this is your first jet there is a learning curve compared to props. Very different. I have the twin engine and pulled slalom skies without issue. Rolling the throttle will help vs hammer down. These have a lot of torque so if you spin up really fast it takes a second to fill the pump, hence cavitation.

For the water and lack of torque in the last. Could be a bad carbon seal. Open up the engine compartment and putter around on the water, have someone drive and take a look around the compartment to spot any leaks. Should be easy to see if there are as well where they’re coming from. If it’s the carbon seal you’ll see it right away.
Thanks DSM and DooGuy for responding.

DSM, I probably didn’t use the right term when I said it feels like it almost stalls. T starts with limited power and takes several seconds before the power really kicks in. I will try to get a video and post the link soon.
Now that I know it isn’t likely leaking coolant I will swap it out. I’ve only ridden it two or three short test drives so hopefully that won’t have rapid corrosion yet.

I am interested in how to replace the carbon ring. 3ftDeep has an article and video but it appears more for the PWC than a boat. Do we have to pull the driveshaft down/out if the carbon ring encircles the shaft? You mentioned this might also be where some air slips in causing cavitation. I would like to better understand how that works.

We had essentially fully loaded the boat when we had the worst of it with cavitation. We tried moving them around, but that didn’t help much. Either way, it happened again when it was just me driving.
A video will definately help us help you.

Hot water in the bilge is normal as stated above. There's only a few places the boat can take in water. Off the top of my head..... bilge plugs (one of mine leaks), steering and shift cables, pump bolts, ICS cable(05 and 06 boats), carbon seal or a leak in the open loop cooling (exhaust and intercooler hoses). All relatively easy to see. A mirror on a telescopic handle is helpful.

The PWC are very similar to the boats so the 3FfDeep videos are a good resource.

What does your rpm do when your having the problem? Is it 8000+?
Will try to get a video ASAP.

I drained the bilge and it doesnt appear to be taking on water.

I am still having trouble finding out more details about whether we would need to remove the full drive shaft to slip the carbon ring around the driveshaft.

The boat starts the cavitation at roughly 6700 RPMs and then it pegs it out with no additional power.

Would the carbon ring likely be the culprit for allowing air in which wouldnt deliver the initial low end torque or thrust when taking off? Someone had indicated that air coming in from elsewhere makes the jet pump work similarly to a straw with a hole poked in the side (hard to get water through).

I am really hopeful that between replacing the bearings and the carbon ring, the boat might be back in the game.
I've never replaced a carbon ring myself, but I can tell you the first step in the process in the shop manual is "Remove drive shaft." If you are considering doing the work yourself you probably want the shop manual.

If the carbon ring is leaking air, that will certainly be a source of cavitation. I have seen posts about putting a zip tie around the boot in a certain way to increase the pressure on the carbon ring to help diagnose if a worn ring is an issue. Maybe if you search you can find and it could be a test to confirm before you go ahead and take it apart?

Check this out for someone's experience with a carbon seal issue and its effect, for example:

Ring carrier / carbon seal was the cavitation problem for me
My 2012 Challenger cavitates just a bit from a dead stop... especially if i throttle too much too fast, I've always wondered if this is normal or an issue somewhere. I've just learned to compensate for it, like someone else said throttle up a bit smoother then gun it :D
I replaced the cooling system housing yesterday. Boy that was a chore. I got it all back together and got the coolant burped and got the kids out skiing again. I got a video of the high RPMs but low speed. It is still having a slow shot out of the hole. I am getting better at driving it, but would love to know if there is anything else I can do. By the time we finished our run, I wasn't able to get it to cavitate at the higher RPMs. The impeller is a 14/20 impeller in case that makes a difference.

Here is a video I did to try to show how it was going:

Also, I took a picture of the carbon ring while I had the engine area open yesterday. See attached image. The ICS cable lock is loose, but I am not sure how to snug it down. It seems like it is quite worn and I plan to replace it this winter.

Thanks again


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