97 XP.. Lower End Questions..

[bobnoodle]

Hello... I am new here, and new to watercraft. I am not new to small engines of all sorts, and I am fairly mechanical. I wanted to buy a machine in need of repairs to get in reasonable, and did a lot of research. I purchased a 97 XP with motor troubles. I believe that I bought it right, so I can do any/all repairs required and still have much less invested than buying one in fair running shape, plus have the benefit of a fresh motor.
This machine would start easily, but showed 150 on the front, and 100 pounds on the rear. I have pulled the top end down, but have yet to pull the pistons from the rods. The rear piston is a bit cooked with the lower ring firmly implanted in the groove. I have not miked the cylinders, but neither has any deep gouging. I am thinking they would bore up ok.
My questions at this point deal with the condition of the lower end. How does one get a real good idea of the condition of the lower end bearings? I am thinking I should have purchased a pump/gauge and pressure tested the lower end before tearing the jugs off to get an indication of seal condition?... When I pull the pistons, I should be able to feel how smoothly the crank rotates... Is that a good indicator?.. The rods don't have excessive sideplay..
I have spent a lot of time reading my manual, and seen a lot of good advice here. I look forward to reading some replies. Thank You! Bob

[SHOOTER]

Re: 97 XP.. Lower End Questions..

I would get an 800 motor from SBT. Their 800 motors are really good, their 800 cranks are excellent. Can't beat the price on it and a peace of mind with a one year warranty.
Go through the carbs, do a rebuild on them.
Go through the pump and change the pump oil, check the wear ring and prop while your at it.
Looking at maybe $1k to $1.1k for the complete setup that I was talking about.
If you can find a R&D nozzle (85/88) and a XO prop, that will give you the best setup as far as pump combo setups. Will make that boat run a lot better.
SHOOTER

[bobnoodle]

Re: 97 XP.. Lower End Questions..

Thank you for your information! I am not certain just what took the rear piston out, but I will go through both carbs and replace filters, and clean out gas tank as a precaution. I will be purchasing a few special tools i.e. degree wheel, pressure gauge, etc to be able to fully test and diagnose issues that are sure to arise in the course of maintaining this thing.

I have done the math on buying a rebuilt crank, boring my cylinders, new pistons, gaskets, etc and it is still a ways from the cost of the complete rebuilt motor. I can believe that the cost differential is more than gapped by the "no fault" warranty. Right now I am trying to balance that with the self-satisfaction of having assembled the motor myself.

The previous owner had the pump rebuilt last summer, but I do believe the value of clean, fresh slippery fluids! I will be refreshing that also.

I also have read a lot on the pros/cons of eliminating the injection pump and pre-mixing. I intend to use this craft for basically just ripping around with no particular purpose except to have fun. What's your thoughts on the great mix or inject debate?

Thanks,
Bob

[SHOOTER]

Re: 97 XP.. Lower End Questions..

I like them both. The oil injection is more convenient. Premix is one less problem to worry about. If your oil injection and your pump fails, your screwed. Rarely happens, but sometimes it does. Either way, they both work great.
SHOOTER

[bobnoodle]

Re: 97 XP.. Lower End Questions..

Thank you for your reply! I have learned quite a little by reading a lot of posts here, and tried to put some of that knowledge to use when I purchased this thing! I will make the final decision as the project goes along.

It keeps bringing a sentiment to mind that a friend of mine used to utter every time he had to put money into his big block powered boat... He'd tell me "Just remember this.. A boat is nothing more than a portable hole in the water to throw your money in!!".. lol..

I would welcome any other opinions on the "rebuild it yourself vs. purchasing a rebuilt" question... Maybe also favorite sources for special tools, motor parts, etc..

Thanks again, Bob

[Bill O'Neal2]

Re: 97 XP.. Lower End Questions..

Well you sound like a knowledgeable type guy who would get satisfaction from DIY.
So, you need to completely disassemble that motor and clean everything. Call SBT and order an exchanged crankshaft and counterbalancer, pistons and clyinders ( or they even sell exchange clyinders with the new bored sleeves and piston kits ), and a complete set of gaskets and seals. Once you have the parts, putting it back together is cake with an oem service manual to guide you.

I sell all of the specialized tools, pop off guages, manuals ect. here at Watercraft Magic, 626 914 9509

[bobnoodle]

Re: 97 XP.. Lower End Questions..

Hi Bill! Thank you for your reply!

I have read many of your posts, and as I gather it, you seem to be at the top of the heap as being knowledgeable in making them run well, go fast, and stay together.

It's late, and I just returned home.. but one thought that has been on my mind most of the afternoon.. If I were to buy a completely rebuilt motor from SBT, I will not have to deal with balance shaft issues. It will already be a good one, and installed... but.. I have to take my chances on whether or not my rotary valve and cover will be a good fit to the crankcases that I would be getting..? If I assemble it with my current one that appears to be in good condition, and I don't have it as tight as I would like, then I am having to dissassemble and do machine work?

The other question.. Did you look at the photo that I had attached to my initial post? I know in the photo the rear piston appears quite a little darker than the front. It is darker, but not to the extent the photo represents it, and the score marks not as deep as they appear. I know the piston is junk, but the theory holds that it likely ran lean on the rear cylinder due to carburation issue..? The tops of both pistons exhibit some wet/carbon/oily deposits, and were both slightly wet, but the rear showed more than the front. The combustion area on the rear cylinder's dome was several shades darker than the front one also.

Your thoughts?
Thanks again,
Bob

[bobnoodle]

Re: 97 XP.. Lower End Questions..

I've been a busy boy here, between work, yard work, and getting some miles on my new Harley in between rain drops. The Seadoo project is a fair weather thing, because it's being done in the driveway. (Camaro project is taking up the whole garage, so the work time on this competes with scooter riding time.)

I am learning things while tearing down and pulling out this motor.

Things like "if Bill says it can happen; It probably will..." i.e. one wrist pin needle bearing falling into the lower end when pulling a piston off...

I also learned that there are approximately four and a half miles of oil/fuel/water lines inside this watercraft, and that someone in the past was on a mission to zip tie them all together!

I did find the source of the oil in the hull. The feed line going into the oil pump had a metal clamp in it, and a zip tie as backup... It also had a leak just upstream from the zip tie. (This likely not only leaked, but it could also allow the pump to suck some air?..) Not sure how much that may have contributed to the demise of this motor, but it's something else to correct. I am going to replace all of the oil lines with new Seadoo tubing, and new clamps.

I did have a question. The drain lines that come out of the lower exhaust side of jugs and tee into one, and go to the back of the craft... Water should be able to pass freely through this hose?.. Mine must be clogged, because when I pulled the head, the water jackets surrounding the cylinders were still full of water.

I am down to the motor mounts and actually pulling the engine from the hull. I have to read over the SBT ordering info as to what to do next to get a new engine ordered. I will also order carb kits at the same time. I also have to purchase a pressure tester.. (I'll be giving you a call on that Bill...)

I better get after this a little harder, so that I make sure I am ready when we get our three days of summer here in Wisconsin!

Bob

[bobnoodle]

Re: 97 XP.. Lower End Questions..

Ahhh... Motor is out... It's now a lifeless lump of aluminum on the bench... lol.. The engine compartment cleaned up well!.. My Mom would be proud of me.. Just enough cleaning to get 'er clean, and no chemicals strong enough to hurt the foam!

Next to tear into the lower end and make some decisions..

Does an SBT 787 motor contain new bearings on balance shaft? Rotary Valve shaft? A new gear on the rotary valve shaft?...

I think posting here is kind of like Captain Kirk and his starlog.. Not sure if anyone is listening, but it seems to make me feel better.. lol..

Bob

[Technical Support]

Re: 97 XP.. Lower End Questions..

Yes, all the engine bearings, seals, rods, rings, clips, pictons, gaskets, etc. are new.

[1fastski.com]

Re: 97 XP.. Lower End Questions..

LIVE LONG AND PROSPER { we listin } all you need to do is use the force luke :-)

[bobnoodle]

Re: 97 XP.. Lower End Questions..

Rockin'!.. My rotary valve is in good shape. Same with the cover.. Generally speaking then, mine should bolt up with an acceptable clearance to the SBT motor?...

My other question has to do with a welded up lower end. Maybe it's just a tic of mine, but I wouldn't want to recieve a motor that has been welded. I know that you back up any welding, but how do I request or make sure that I don't get a motor with any previous weld repairs?

Thanks for the blazing fast reply!

Bob

[Technical Support]

Re: 97 XP.. Lower End Questions..

You cannot request such a product, nor is there a need to. If you want a gauranteed new condition case, you'll need to buy it elsewhere or do it yourself.

Yes a good condition cover mounts to the new engine, it has stock tolerances.

[bobnoodle]

Re: 97 XP.. Lower End Questions..

Thanks for your reply.. You're on top of things!

Please don't be offended that I asked about the welding issue. Also please understand that I am in no way berating your welding services, because I have had no experience with you to base that on.

However, I have had enough experience with welded crankcases on other motor types, and it's just a preference of mine. My cases haven't been welded on, and I prefer it that way. I will have to arrange my refurbishing plans accordingly, but I may purchase other items from you that are incidental to this project. Customer base built by word of mouth is the most powerful kind. Like a tree, it continues to branch out $799.00+ at a time. I don't understand pruning my branch at the expense of a simple request...

Thank you, Bob

[Technical Support]

Re: 97 XP.. Lower End Questions..

No offence was taken whatsoever. It's a fairly common question we get asked, I'm just letting you know up front so that if that is important to you (as it is to some other people, you are not alone) you can begin to plan otherwise.

That being said, only a small percentage of the motors ever need welding.