In So Deep I'm Drowning With The Skis Still On The Trailer

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I bought a couple of jet skis on impulse last year in pretty good shape from the perspective of someone who had built everything you'd want on land. I was warned about a bad battery in the smaller one I intended my girl to use and all summer carried cables until our last ride when a well meaning person pulled her battery to charge and put it in backwards. I'm hoping only the battery was destroyed considering by then every start required a jump. I'll know today probably when the new battery is in. We also ended up with other issues over the year, but every single one has been impossible to get clear answers for from anywhere. Here's a list.

Her ski when jumped would often rev with no thrust for a bit but be fine after a few minutes or a shut down and restart. There's never been a blockage in the intake. Mine on our last ride started doing the same and I'd have to just idle around until it started going. Then I'd try to pick her up since hers was done until I got a battery and it would start again until I got her off and repeated the idle nonsense until we gave up. We drained the water before winter and I'm doing prep work to get them out now. According to 3 SeaDoo history sites and also hours reading forums, I have a 97 GSX via a piece of plastic on the deck that looks nothing like the HIN tags in pictures, hers has a number pressed into the fiberglass in back which ends in 95, no other marks or anything like a tag. Forums pretty clear that I have a 787 engine, but history sites only list a 750 or 951. I know 951 is possible but was a GSX Limited via forums. I believe she has a 540 but have done less digging. I'm trying to find a good comprehensive guide to preseason work that should be done, eventually a winterization one as well. If someone knowledgeable can just link a good one that would be enough as none I find seem consistent and I'm too new to know if something critical is missing beyond common sense motor stuff. Next is this cavitation problem. Why isn't it consistent? I did suck up gravel once and killed the engine instantly. Then pushed back out and rode another 6 hours without issue. I can't be as sure on the SP, but can confirm its also an issue that has happened multiple times and then cleared on its own with at least 8 individual day long excursions and was only parked because of the season ending and the battery fail on what was going to be our last time out anyways. Now that I'm many hours deep into learning about the issues unique to skis in general and some unique to my models, I can spot things I never knew to look for. GSX wear ring looks tight and pretty smooth but the impeller is for sure damaged with each blade bearing divots, scars, and even a quarter sized piece missing on one blade. There's no question about changing it. I haven't checked the SP yet but expect similar results. I've got my wife saying take it to a shop, a dad who's is incapable of letting anyone finish a thought before interjecting his opinion and any attempt to further explain is met with increasingly hostile interruptions of the same opinion, in this case he agrees I need a prop and while there a wear ring, but I must use OEM. I haven't found much on labor costs to have those issues corrected but assume it's considerably more than a car or ATV. Anything much more than $500 labor and it's not worth it as this doesn't seem that hard if you're skilled with mechanical builds and repairs. I will almost exclusively use them on inland lakes, maybe rivers but having learned about how fragile they are with debris I may avoid that entirely. Finally they may make one trip into Lake Michigan if I think we can handle the swells having never been anywhere close to those conditions. I've looked at stainless impellers and the added durability sounds pretty great, the performance boost doesn't matter as just getting one not so damaged will be significant and we were happy already. They already exceed our states speed limits. And a stainless wear ring would outlive the craft in a good way I've read. The downside there is the ring would corrode onto the housing and outlive the machine again, but not in a positive way this time. By making it a lot tougher there, when damage would normally occur where's it now going to happen? My boat has a sheer pin to protect the motor if I destroy a prop. I haven't seen anything similar in these. OEM is pretty darn cheap plus buying the tools to do it, but a full Solas kit is only about $80 more with the tools included. Please, weigh in any thoughts on which direction you went and why. If you can point towards a nice idiots guide to any of this stuff, please do. I'm not too lazy to do my own research, I just seem to keep finding contradictory info in everything I read/watch.

Next up is the Variable Trim System. This is pretty much an afterthought for me at this point, but I have zero knowledge or experience about it in real world. When I purchased it i was told the system didn't work. Nothing more. So no idea why it doesn't, just that the buttons do nothing and the trim indicator is always stationary. Usually if I was told something is broken at purchase I'd replace it before ever using it. In this case he pointed out that the SP doesn't have the system as well as many other models, so it never seemed important. I was just more than happy to enjoy the experience at all. The seller couldn't explain it's purpose any better than it adjusts your prop wash up and down for planing out. If anyone has a more practical explanation to its purpose or function and why it's worth dumping hundreds into replacing, I'd be interested. Like say it's something that will create a more noticable acceleration or somehow helps with control or speed in situations. All I'm grasping so far is you adjust it based on how you're planing to compensate for the pitch or angle.... For uh... Reasons? Yeah, I'm clearly not grasping it as it's obviously not critical to basic operation and can only assume it's performance oriented but don't have a clear concept of how yet. It might as well be a wing on a Honda the way I'm using it.

I've got new batteries installed, new plugs, about a half tank of fuel from last season that I'm adding some Seafoam to and will top off, fill the oil mix tank. I planned to start them up at that point to run a few seconds and ensure they're ok there and not having any motor issues from the older gas, rotted hoses, carb issues. Next I'm going to start looking into how to change out the various oils like gear lube that I'd like to drain and replace with Lucas. What else am I missing? I'm about to watch videos on the proper care and maintenance of jet skis, so if anyone has a good one, that would help. Both mine are 2 strokes. If there's a GSX or SP specific collection of information that would be even better. My apologies for the length and all over nature of this. I just have way too many questions and every attempt at finding answers brings nothing but misleading, inaccurate, contradictory, or flat out wrong information. I can't even find a correct location listing for my HINs, having to make an educated guess by ruling out multiple locations identified by various sites supposedly being dedicated to providing a complete collection of fact and history of Sea Doos. If it's not anywhere it's supposed to be, the only place left is the spot it's not supposed to be. Even if it's different every model and year.

TL;DR I'm new to PWCs but also very capable of fixing my own stuff. I need clear and correct info on various things as I'm constantly finding new info directly contradicting old info. I also need the correct info for my specific PWCs as every site with model specs contradicts each other and random forum posts comments have been the only accurate information I've found. Why does PWC cavitation happen intermittently? Can the battery have any effect on it? As dumb as it sounds, my battery issues always happen in tandem with cavitation and so frequent coincidence seems unlikely. Again with information, where can I find a good collection of information on various aspects of these machines like features and accessories from beginners to mid ability skills, topics that cover all the basics every owner should know. Any good source for preseason prep (also eventually post), preferably 2 stroke specific if not model specific, and a comparison of high maintenance/performance item selection and installation.
I found everything i needed on this site, including human expertise to expand on the existing posts.

Random cavitation could be a weak bellows.

I couldn't read the wall of text, skipped down to the tldr, sorry. But really, start a post with a particular problem and if it's a smoker you'll get to the answer here.
What I gathered from your post and my input...

You own a GSX and an SP. You're having cavitation issues and want to know if an OEM wear ring would help. Yes, I only have bought an OEM wear ring for my skis, they work well. You're wondering if Lucas oil is good to fill in the pump. I guess it would be fine, but use a 75-90w gear oil. I personally use Valvoline Full synthetic 75-90w.

You're debating about a Stainless Steel pump upgrade I'd assume for the SP, yes, that's a good upgrade, no downfall to doing so.

Couple things you want to stop doing, 1. NEVER jump start the ski, you're gonna fry something if you continue to and really create an expensive problem to fix. 2. Never use Seafoam, it's unnecessary and can mess up the carbs.

When in doubt about run problems, rebuild the carbs with OEM kits, replace the fuel lines, replace the fuel selector, and the fuel strainer oring.

When in doubt about cavitation problems, pull the pump and check the wear ring clearance, or replace it.
Well you’ve got a ton of quest there, so it’s probably going to be best to break them down into bite sized pieces so that all of us, yourself included, can wrap our heads around what’s going on... Unfortunately there aren’t any real good write ups that break down maintenance as a whole. That’s mostly because there are so many different models and engine combinations that have slightly different procedures and specifications. Luckily there’s plenty of help to be had here if you’ll start a thread for the individual problems you’re having.

I guess let’s start with the battery issue on the SP. That model has the 587 engine in it, and uses a rectifier/voltage regulator to convert the AC power from your magneto system into usable DC power to run the ski and charge the battery. It’s very possible that you just had a bad battery and that problem will go away when it’s replaced, but it’s worth putting a volt meter on it while the ski is running to verify that it is charging. You should see 13.5V-14.5V. If you’ve got less than that, you’ve got a charging system issue. If you were to see more than that, you’ve got a rectifier issue.

As for the cavitation, you shouldn’t really have anything intermittent going on there unless you’re riding in an area with quite a bit of vegetation. It’s possible to suck up some weeds and experience brief cavitation until the prop chews it up and ejects it through the pump. With the description you have of the impeller, I’d be willing to bet you’re experiencing some degree of cavitation all the time, but it becomes far more noticeable when the pump tries to load itself up. Normally I’d recommend just having your impeller reconditioned, but if you’ve got quarter sized chunks missing, it’s time to look for a good used one or an aftermarket upgrade. Just make sure that you replace it with one pitched correctly for your ski.

The wear rings will almost certainly need replaced. You can go OEM with those, or you can go with the Felton rings, but I would avoid the cheap blue rings. They tend to be out of round and have a bit of taper to them, so they don’t fit snugly against the impeller all the way through the pump. I’d advise against stainless wear rings for a recreational ski. The wear ring is exactly that, a wear item. It’s designed to act like a fuse in the system, so that debris will wear on the “sacrificial” ring rather than the expensive impeller. Going to stainless takes that leeway out of the system and makes it far more likely that rocks or sticks will either eat the impeller or lock the pump up completely.

As far as maintenance goes, the number one thing to keep an eye on is the fuel system. I always go through the whole system on any ski that’s new to me, even if the previous owner swears it was just done. The carbs need rebuilt with GENUINE Mikuni parts, any grey fuel lines need replaced with black automotive lines, and the fuel selector needs to be replaced. Don’t clean it, as that can make them leak air even more, just replace it. The o-ring on the water separator also needs to be replaced.

The oil system is the next major maintenance area. Only use API-TC rated oil. Don’t use anything that’s TCW3 rated. On the SP, you can use mineral oil, but the GSX needs a full synthetic, as
Yeah, sorry about the wall guys. An accident awhile back left me with some lasting quirks along with the broken spine and brain damage. One of them being I couldn't communicate verbally or express thoughts understandably while stuck in a bed for a couple years. I have to make an active effort not to create thesis papers when I express thoughts or ideas. It's a loop where everything feeds everything else. Like autism with cocaine? Maybe I should add a disclaimer to my username..

Great information! Thank you, this is the kind of information that you have to piece together bit by bit searching as a lot is so basic no one mentions it or you end up on those sites of junk trivia that actually are half wrong. I figured asking an active community of people who live these things would get me a great start! sorry to hear of your past physical issues....those notwithstanding.....attack the ski issues piece by piece.....How do you eat an elephant, ONE bite at a time.

The skis are pretty basic machines......#1: Good battery, #2 Clean/Rebuilt carbs, #3: Clean fuel. Everything else is secondary and typically contributes to any ski issues. Will need to test compression, etc....

Post short questions, with general background info and we'll jump in with ideas, solutions, encouragement as needed :), and it begins........
Sometimes you can find answers and information by searching the forum. Our problems are not all "unique" to us alone so chances are someone asked the same question and got good responses. If you get out there and begin working on the ski you'll figure some things out and will be able to not only ask pertinient questions but offer insights as well. Good Luck.... welcome to the journey.
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