jpwhit

You have to pull the impeller out to tell if there are any issues. Sometimes there is chunk missing out of the middle of one or more of the vanes. Also check to make sure the rubber isn't spinning on the hub. Sometime the bond between the brass hub and rubber part of the impeller breaks free. When that happens the impeller work somewhat but will slip enough to allow overheating in certain conditions. It's likely the conditions you were running the boat did make the issue show up, but it's not normal and it shouldn't have happened. I'd say something is definitely wrong, but not something that's so wrong it'll show up in other scenarios. But it would be best to find and fix the problem now, before it gets worse. A likely culprit is a small air leak somewhere on the suctions side of the raw water system. Something letting air in between where the water enters the hull fitting and the intake side of the raw water pump. Most MasterCrafts have clear fittings on the connections to the strainer. Look at those carefully when it's operating in the kind of conditions where it overheated. You shouldn't see any consistent pattern of bubbles in either of the two clear elbows on the raw water strainer. If you do, then that's a clear indication of air leaking into the system, at least up until the point of the strainer.

All of our mainlines have lead weights. They aren't floating up above 5 feet when just sitting there. I've checked for that. We've even had the same thing happen with stainless steel mainlines. And they certainly don't float.

Yeah, you would think that's the case, but our experience is that unfortunately it's just not always the reality. Our mainline is 5 feet down and people still snag it with props on average once a season. It's amazing how deep a badly trimmed I/O can grab a mainline. We've literally been out at the course and watched it happen. Never happens when they cross perpendicular to the course, it's always when they are running down the center over the mainline. So, I think there's as aspect that the prop pulls the line up. Our course is only in 7 feet of water, so that may be a factor as well. We've also seen cases when they get a boat guide line in the prop and it winds the course up and then pulls the mainline and pole into the prop.

I have a couple of courses on Kerr Lake, so not far from you. We have more than one because depending on water level and other factors we change location. I also have friends on Kerr with courses as well. There are at least 4 courses on Kerr that I know of. We all used to sink them, but since the pandemic we've all been leaving them up 24/7. We know the WRC officers on the lake and as long as we play nice with the fishermen and other users and they don't get complaints, they are happy to look the other way in regard to the letter of the rules. One word of caution on the stainless steel mainline, because I've used both on the lake, if someone snags the SS mainline and gets it caught in their prop, they won't be able to get it free without tools that people don't typically have on the boat. You often have to take the prop off to get it free because the thinner cable can go between the gap between the prop and the lower unit on an outboard or I/O. That's not good for us for two reasons. First, it can result in complaints which will upset our status quo with the WRC, seconds if someone's boat is captive and they can't get free, they will end up pulling up the entire course and taking the mainline. It's also more difficult to repair SS mainlines when they do get damaged. Our group has used insta-slalom courses, accu-float, and ez slalom courses. And while they all have their pro's and con's, they don't seem all that different. I've also used insta-slalom mainlines and just made my own PVC booms as well. For courses that you leave in the lake, it's pretty easy to just glue together PVC pipes to make the booms since they don't really need to come apart if you aren't taking the course in and out. I've even made my own mainlines and when I do that, I make them in symmetrical sections that are connected together by SS carabiners. That way everyone that uses the course keeps an extra mainline section in their boat. If the course gets cut, we just replace the cut section. But I will say it's more time consuming making your own parts than it seems like it would be. So I think it's often worth the money to buy pre-made mainlines. I also have friends with houses on Gaston. One really close friend's house is around Lizard Creek. I mention that because I've been teaching their young adult daughter and her boyfriend to ski the course and they've asked me if I knew of anyone on Gaston with a course. And I do know about the course right outside the Lizard Creek culvert that I think is maintained by the Pro Wakeboarder that lives around there. So that's probably best option for her and her boyfriend. PM me if y'all want to come over and ski sometimes. You wouldn't need to bring any boats over.

The standard LCD panel in all the Zero Off head units that I've repaired had a semi-custom LCD assembly. It's pretty similar to a standard 128x64 LCD, but it has an FFC connector directly on the LCD that's not typical. To repair them, I ordered a high quality standard 128x64 assembly that is based on the same LCD controller and fabricated an adapter to go between the LCD and the FFC cable. I also had to add a level shifting circuit for the LCD contrast control to work correctly.

Never use any kind of abrasive on a machined metal mating surface. Even with a razor blade or putty knife, you always want to keep a fairly shallow angle to the metal surface so you don't put any scratches in the surface. It's not typically difficult to clean off the surface with a razor blade based scraper. It's just easier with something sharp like a razor blade to get under any remaining gasket material. The only time it's difficult to clean a gasket surface is when the gasket was put on with some type of sealant. But that's typically never the case for exhaust system gaskets.

I use a combination of a razor blade window scraper and a putty knife to clean off the matting surfaces.

Even though it has a distributor, the timing is controlled completely electronically by the ECM using the crank and cam position sensors. Rotating the distributor doesn't change the timing, but it does change what they call Cam Retard Angle. You can only set Cam Retard Angle using Diacom. It basically setting the distributor position such that the rotor lines up with the right spark plug terminal in the distributor cap as close as it can over the typical range of the electronically adjusted timing. If it's off, you'll get the spark jumping to the wrong terminal within the distributor.

I've repaired a few. PM me and give me a little more detail. What boat / year and if it's just fading or the display is completely dead.

Good luck! I hope you can get it running for the rest of your vacation. I guess this is the first you're using it this year if it was winterized.

I didn't realize it had overheated. If that's the case, even if the head gasket is the cause, it'll be likely the heads and/or the block will need to be resurfaced. This will be even more true if it had TTY fasteners. That's because the advantage of TTY fasteners is that they have a bit of elasticity. That keeps the pressure on the head gasket more consistent with changes in temperature. Whereas when an engine overheats with non-TTY fasteners, such as studs, the expansion of the head and block at high temperature tends to crush the head gasket. Then when it cools back down, you no longer have good even pressure on the head gasket and leaks form. With TTY fasteners, that does't happen as much. So, when the head gasket leaks, it's more often due to some warpage of the mating surfaces. What caused the boat to overheat and how hot did it get?

The tightening sequence is in the link I posted in the initial post of the thread.

Responding to this PM on the open forum because it seems like info that others may need at some point. Ilmor doesn't provide specs or any info on head bolt tighten sequence in the official service manual. They are very clear in the official service manual that dealers should just order a new bobtail engine from them for any internal engine issues. There are 2 generations of head bolts for the vortec LS engine series. The later generation can be identified by having a captive washer on the bolt. GM specifies not to re-use the 2nd generation head bolts because they are torque to yield. To always replace them. They are less clear about the first generation bolts. You're suppose to follow the tightening torque sequence as specified by the bolt OEM. This is the procedure for the GM OEM 2nd Gen Torque to Yield head bolts. https://help.summitracing.com/app/answers/detail/a_id/5187/~/how-do-i-install-my-ls-cylinder-heads%3F You also typically need new intake, exhaust, and valve cover gaskets in addition to the head gasket. You can likely get away without a new valve cover gasket. I'd say 50% of the time the exhaust gasket doesn't come apart on disassembly. I've never been able to save and re-use the intake manifold gasket. John

The head unit provides power to the puck. I think it's possible the puck is shorted out and trying to draw too much power from the head unit.

I would offer more input, but this is the kind of issue that's nearly impossible to be of much help remotely. There could be a lot of things that would cause this, but I wouldn't rule out water in the tank. Especially if you always run non-ethanol gas. We had a similar issue with our 2012 Nautique 200 club boat building up water in the bottom of the tank when we ran non-ethanol gas. It happened twice actually. Now we run ethanol gas except over any winter storage and haven't had any more problems. Our club boat doesn't get much time off, so there's not a lot of winter storage. FCC will separate out some water, but not if there is standing water in the bottom of the tank, when it gets up to the level of the fuel pickup, you start getting a steady stream of water mixed in the fuel that causes random misfires. Fuel additives won't get out that much water either. The misfire detection in the ECM won't detect this either. It really can only detect a consistent misfire in one cylinder that happens in a consistent pattern. It looks for patterns of inconsistencies in the rotational velocity data from the CPS. I have a separate outboard motor style gas tank I use to help diagnose issues like this. It even has its own electric fuel pump, adjustable pressure regulator, and pressure gauge to make it pretty universal. But you actually don't need all that on a Nautique since it doesn't have an in-tank fuel pump and pressure regulator. Just connect an auxiliary tank to the input of the low-pressure fuel pump. I also have Rhinda Diacom, and I've recorded a lot of reference files for most of the key sensors for the boats I work on regularly. That way I have something to compare against when something starts acting up. It can be useful to just look at the sensor reading w/o having references, but it just makes it even easier having them. When things get really deep, I also have a digital storage scope for all my electronics work. I have HV clamp on probes for that that can monitor each spark plug to look for misses. And I have fuel and cylinder pressure transducers I can hook up as well. Not sure this will be all that useful for you....good luck, this is the type of problem that can be pretty challenging to diagnose.

ZR4 doesn't have a distributor

I assume you've checked for Engine Codes via the LINC screen.

MasterCraft introduced power Surf and Wakeboard racks.

That's right. Clarion, then Fusion starting in 2014, and then Kilpisch in the latest Mastercraft's. Fusion was by far the best. Everyone hates Kilpisch in the newest boats. A 2010 will be the original LINC and there is no firmware for the original LINC to support anything but Clarion. Matter of fact, the original LINC is no longer available as a repair part, if you need to replace the LINC screen in an early 200, there is an upgrade kit to install a LINC 2.0 screen. But it's about $5k. My 200 has the original LINC and the Clarion stereo, and I was at the ski club today and turned it on to see if it even worked. We never use it at the ski club. It did actually work, and I could control it from the LINC screen. I didn't have time to look at the connection between the LINC screen and the Clarion head unit. But I'll look at it later this week or early next week.

What do you mean by "Nautique driver display/control bus"? Do you mean the LINC screen in the 200? The audio interface between the LINC screens and Clarion stereo's is something fairly proprietary. I'm not sure if the same interface as the Clarion remotes. What year 200? Is it the original LINC screen, LINC 2.0, or LINC Panoray?

It's really worth getting a more modern ski. I'd recommend a Radar Senate. You can find them used for very reasonable prices.

@SiPitts is correct about how these gauges work. And a pretty typical failure is the stepper motor (clockwork) fails in the gauges themselves. They aren't that hard to fix, but it's a little tedious. The MDC provides the signals to drive the gauges and they also seem to fail somewhat consistently at a certain age. I suspect they have the type of electrolytic capacitors in them that dry out and fail after a certain age. I've never taken an MDC apart to investigate the cause of the failures. Fixing it depends on whether the problem is in the gauge or in the MDC itself. Often the gauges are daisy chained together. So, if one gauge on the same daisy chain isn't working, and you move its position in the daisy chain and it still doesn't work, then that's almost always a problem with that gauge. If the gauges after a certain gauge on the same daisy chain do not work, then the gauge before isn't properly passing the signals through. I think some MDC have more than one output so they can be multiple chains, or certain gauges may have a dedicated output. If all the gauge suddenly quit working, that's almost always the MDC itself has failed.

Given all the tests you've done, it's pretty likely failing components in the MDC. And if it's not the MDC failing now, it will be in the not so far off future. If it were my boat, I'd go ahead and start the conversion away from the MDC to gauges that don't depend on the MDC. Since your speedo is broken now, I'd just go ahead and replace it with a GPS based speedo. You could go ahead and buy a full conversion kit now, and just install the speedo until you start to have other gauge issues. Or you could just buy the speedo now, but it would be worth it IMO, to try and get a speedo that will match later if you have to replace the other gauges. Does the boat have speed control? If so, is that working? Is that also getting it's speed input from the paddlewheel or is it GPS based such a Perfect Pass Stargazer?

Having the same course mapped twice can cause the type of issue you've described unless you disable the feature where Zero Off tries to automatically select the course. I'm assuming this is the single GPS puck Zero Off? If it happens to be the older dual GPS puck then there could be other issues.

When I looked at your picture, I realized that it looked familiar. Then I figured out it's Seven Lakes. You're not far from me, I live in Cary and my lake house is at Kerr Lake. The ski club I ski at is in Willow Springs. Like you, I've skied since I was very young, but I got into course skiing in a serious way when my twin daughters started college and skied for the UNC ski team back in 2010. That's also when we joined the ski club in Willow Springs.