Charleston 1996 Challenger Project

[eddie708]

Before putting anymore money into it get a updated compression test. if u get 150 and 125 again its time for a motor. if u didn't already replace fuel lines and clean the carb filters start with that. also if you do a search u will find that the only recommended starter is oem anything besides oem is considered junk and will most likely stop working within the first few months. u can rebuild ur oem starter for under $40. if you rebuild your carbs only use mikini carb kits. i would also recommend sending them to dr.honda, jetski carbs are more involved then most carbs used on dirtbikes and atvs and most new guys will not get it right there first time. i know i didnt. As far as only reving to 3500 start at the regulator. it the box with 3 yellow wires and 1 red comming out of it. unplug the red wire and then start the boat and try it.

 

[Charleston]

Thanks to you guys here and a PM from Billy, I know at least one issue here. My Rectifier is bad. So bad it is missing. I guess they took it out before selling to me. This explained the wires hanging out. :cheers: Funny thing is the local Seadoo store said they thought they were for most likely for dealer options. Yes, options....like going fast. After I saw a pic of a rectifier it explains the wires hanging out and the missing void in the elec box.



Part should be here Friday/Saturday. I'll let you know what I find once installed. I also found these seadoo-forum posts:

http://www.seadooforum.com/showthread.php?67228-98-GTX-running-issues&highlight=rectifier
http://www.seadooforum.com/showthread.php?31491-Testing-the-rectifier

the only recommended starter is oem anything besides oem is considered junk

I agree and got OEM starter. Had no clue I could rebuild it. It is crunchy. I did hook it up to battery and it jumps but it is real crunchy. Bearings?

I do have a spare set of carbs now and a rebuild kit. Mostly just sitting on the side. Not sure what costs would be involved to get a rebuild. Second set is most likely not tuned to my toy.

As far as an 787/800 engine rebuild....no clue. I am sure there is something somewhere here on the boards about it. I think that will be outside my ability. Not even sure how heavy these little engines actually are. Shipping has to be nuts.

Charleston

 

[eddie708]

even with the rectifier removed it should rev up fine. like i said before do another compression test. if the motor is no good u can try tuning it all u want but it still wont run right.

 

[Charleston]

Tomorrow is the test.

On a funny sidenote, I am now the owner of a second 1996 Seadoo Challenger with a blown motor. I can tell why they blew it as it was modified with a R&D head/arrestor and a Rossier pipe. Most likely got another 500rpm out it. Either way, motor is toast. Best news is it had a very nice trailer and bimini top as well as a spotter seat. So....that being said. Cool beans. Also had my missing Rectifier.

 

[Charleston]

Friends,

I wish I could have said I told you so but I cannot. The boat performed better but cannot push past 4k under a load (water). Sitting in trailer (and in drive) it rev's past 7k now. So the missing rectifier was part of the issue. I reran the compression test and got 135 for the front and 155 for the rear. Here is the pics of the pulled spark plugs. The right stark plug came from forward cylinder that had the lower 135 reading. It is darker in color. Both spark plugs are new.



At least the heat of the season is gone. It is nice but I am seriously considering taking it to a shop to get run over the coals. I have looked online at new motors. If I have to shell out 800.00 for a new motor, I sure as heck want to be sure I need one and it is not something else.

As for the second "parts" boat, I am the owner of a nice new bimini top, a newer painted shorelander trailer (we swapped them today), a spotter seat, and a few odds and ends. Took off the Rossier pipe. Also got me a functioning speedo sensor and a rear light pole assembly.

Feel free to chime in or PM with with parts or engine queries. I will most likely be looking for a new 787 motor in prime status. Not sure why a minor change of 155/135 would cause this much performance issues but it could be that difference that imbalances it.

Charleston. :facepalm:

 

[eddie708]

if you wanna keep the boat and are willing to put some time and money into it then i would start with a new motor and rebuilding your fuel system. 155 and 135 is a big difference in compression, most likely one of the carbs got plugged up with gunk from the gray fuel lines and started running lean

 

[IDoSeaDoo]

The spotter seat makes all the difference, I'd keep that boat instead. Trust me, you'll use it. As for the compression, I'd consider at least doing a top end. Make sure you replace those wrist pin bearings and don't drop any of the old needle bearings into the lower end. I ruined a freshly rebuilt motor that way (you never get them all out after something like that).
Good luck!

 

[Charleston]

if you wanna keep the boat and are willing to put some time and money into it then i would start with a new motor and rebuilding your fuel system. 155 and 135 is a big difference in compression, most likely one of the carbs got plugged up with gunk from the gray fuel lines and started running lean

I have no grey lines on this craft. All were replaced prior to my ownership. They might not have done a carb rebuild so the gunk could be in there.

Looks like IDoSeaDoo is suggesting a top end rebuild also. I found this interesting video about the top end rebuild. This part does not look too hard.

http://www.youtube.com/watch?v=5EEB9gRWuxo

Based on what I saw here (the damage), I am going to open up my heads to inspect for any damage, check for wear, etc.

Has anyone here ever done a top end repair on a 787/800 motor? If so, please feel free to post a reply or PM me about your suggested manufacturer/makers and any websites, etc. Sure someone else would like to know too.

From Ebay I found these fellas:

http://www.ebay.com/itm/Sea-Doo-787-800-Engine-Top-End-Rebuild-Kit-w-Cylinders-Piston-Save-150-w-core-/111195812428

http://www.ebay.com/itm/Seadoo-787-800-engine-top-end-rebuild-kit-pistons-bore-/321206705723

Charleston

 

[IDoSeaDoo]

Those WSM kits from ebay are going to be the cheapest route, but they rarely come with wrist pin bearings. Many here will tell you to replace the crank too as its probably old and tired. I've had mixed results in replacing cranks. They're pretty much all on borrowed time at this point, I've had a couple fail, but there's always been a reason for it, whether it's water leaking into the cylinder or overheating.
If you opt to do the top-end only, be sure to do a leak-down test to make sure your gaskets mated properly (and that your lower end seals are still good), be sure to check your piston-ring end-gap clearance, be sure to hone your cylinders upon reassembly, and be damn sure to install the pistons with the booster ports (those holes in the side of the piston) facing the carburetors. There's usually an arrow on top of the piston that should point toward the carbs too.

Good luck

 

[racerxxx]

I just looked at the pics on the first page and it looks like the engine is silver? If so someone has already replaced it. With a mirror look on the front of the MAG cylinder and see it there is an SBT sticker with a serial number. You can call SBT with that number and find out when it was sold. Personally I wouldn't bother putting a top end on an SBT engine since it is probably already bored and if that low compression cylinder is scored.....you're going to have to go bigger yet. First thing I would do is rebuild the carbs, $100 for the Mikuni kits. Then run the boat as much as you can, if the engine lets loose just get a reman'd engine and you can have it back on the water in a few days, also no sense in doing it over the winter if you're not planning on using it anymore this season. Why have that cash just sitting unused. You're at about a $600 differential between a top end and a full reman. Just my opinion.

 

[racerxxx]

Those WSM kits from ebay are going to be the cheapest route, but they rarely come with wrist pin bearings. Many here will tell you to replace the crank too as its probably old and tired. I've had mixed results in replacing cranks. They're pretty much all on borrowed time at this point, I've had a couple fail, but there's always been a reason for it, whether it's water leaking into the cylinder or overheating.
If you opt to do the top-end only, be sure to do a leak-down test to make sure your gaskets mated properly (and that your lower end seals are still good), be sure to check your piston-ring end-gap clearance, be sure to hone your cylinders upon reassembly, and be damn sure to install the pistons with the booster ports (those holes in the side of the piston) facing the carburetors. There's usually an arrow on top of the piston that should point toward the carbs too.

Good luck

The arrow points to the exhaust, just so happens the 787 has the carbs AND exhaust on the same side. Not trying to nit pick, but if someone with a 720 or smaller engine were to read this, it would be wrong since the exhaust and carbs are opposite, arrows always to the exhaust.

 

[Charleston]

I am starting to research a replacement motor. While on the phone, one dealer was telling me I needed a special 787X motor for the challengers. He didn't get into much description of what is uniquely different between the 787 and the 787X. Does anyone have any insight to this.?

 

[racerxxx]

Nope, just a standard 787 is what you need. If you look at the tag on the engine near the rear motor mount that is bolted to the engine you will see it. In the corner it should read TYPE:787. If for some reason yours says 787x the you will need to change the PTO which is no biggie. I'd be interested in seeing what your tag has on it. It's possible someone swapped a 787X engine in you boat in a previous ownership.

 

[IDoSeaDoo]

Yea, the guy is full of it. As far as I know, they never put 787x motors in the Challengers. Even if yours IS a 787x, you can still drop a regular one in there. Man, seeing this thread again, I realized that I really miss driving my Challenger. I never get a chance to do so anymore as it gets dark at freakin' 5oclock now-a-days. Winter sucks!!!

 

[Charleston]

Still here. Cooler weather put other fun stuff on the hotplate. Good news is I have a new engine with 155/155 ready to put in to replace the old one. I am planning on removing the carbs possibly this week for a rebuild. Was watching a few videos on it on YouTube. Doesn't look too tough.

I have seen a few articles on how to pull the engine but no videos or picture vs picture layouts. I am hoping these are pretty much plug and play. Feel free to add links to anything you think a first time engine remover could use with modest technical ability.

Thanks
Charleston.

 

[Charleston]

Today I was able to get the heads off to take a look. I have seen a few pictures in the past where low pressure means all hell broke loose in the cylinders and even some times there was an impact of some type. This is what I saw:


As you can see and remember from previous posts, my low compression was showing on the front cylinder. From these pics you will notice an enormous amount of carbon buildup on the front too. That line was my finger nail on the top of the piston.

What do you think?

 

[Charleston]

So, I took the time to clean the heads. There seems to be some pitting here and there randomly in the dome. No impacts noticed. Here are the new pics:



Any insight? I do have a new engine ready but would hate to do something crazy for something that could have been repaired easily.

Close inspections also saw no scoring on the piston walls. I was expecting to see things torn up in the one cylinder.

On a side note I just listed a Rossier pipe on Ebay for the 787/800. Came off the "parts" boat. LOL.

Charleston.

 

[Charleston]

This was the weekend of engine removal. That is done.



While trying to reinstall, I noticed that the new engine had the ignition housing (P/N 290810711) damaged during shipment making it egg shaped for starter connection. Cannot get starter in. Here I need some questions answered:

1. Inside of the magneto assembly I saw a lot of rust. The ignition housing is being replaced. The hub flywheel (P/N 29096644) looks like it is built like a tank but it is completely rusty. Rust attached to the Magneto Flywheel (P/N 290886598) can be relatively easily removed. Are these hub flywheels ok rusty? Is there anything I should do to inspect once removed?



2. Oil seal (P/N 290830749) and gasket (P/N 290931470) are both located between the ignition housing and the engine. Should both, either, or none of these be replaced during the swap?

3. Finally, how the heck do I get this off? I got the cover off and I just cannot seem to be able to get the nut off for the hub flywheel! Tricks? Anyone know what size this uses. Seems all my sockets are a little loose. Shows M18 nut but that just isn't correct. 27mm is a little too loose and 24mm won't fit. Nothing English seems to fit.

Thanks
Charleston

 

[Charleston]

Just looking also at the magneto assembly. My new engine came from a GTX which has some different P/N's within the Magneto assembly. Documenting this for someone who may be reading:

290966442: superceded: 290966441: superceded: 290966440

Therefore same P/N. You may find the 440 stupid priced compared to the rest.

 

[IDoSeaDoo]

1. Magneto hub can be rusty, all it really does is house the magnet that spins around the stators. A little rust shouldn't hurt it. I'd give it a shot (unless you have deep flaking rust).
2. While you have it apart, I'd go ahead and replace that seal. It's inexpensive, and worth the peace of mind. If it's bad, it can cause a lean condition (2-stroke nightmare). When you order that seal, be sure to get that gasket for between the mag housing and the crankcase.
3. As for the nut, use a 27mm socket. Lock up the motor by either jamming something in the flywheel gear, being careful not to cause any damage, or feed a length of nylon rope down into one of the spark plug holes. Use the seadoo flywheel puller and a little propane to help it release. Using a standard puller is much harder and you will go through several of those thin bolts in the process. The puller can be found online for less than $30 if I recall correctly.

 

[racerxxx]

To remove the flywheel you need to pull the nut off the crankshaft then use a puller that will grab the threads on the hub of the flywheel. You can leave the mag cup on the flywheel to do this. Install the puller and tighten down the center bolt , give it a good whack with a hammer and it should pop. Then you can get access to the screws that hold the housing on. Then replace with your new housing, gasket and seal (both new). Put grease on the shaft and liberally on the lip of the seal before reassembly. Put blue loctite 242 on the taper of the shaft before you reinstall the flywheel. You don't want to start the engine with the seal dry so use the grease. Also inspect the crank where the seal rides, sure hope it's not rusty.

The nut is 27mm or 1-1/16"--how's that for a metric fit! The nut measures 1.045" or 26.55mm. Choose the one that feels tighter. I think I usually use the SAE not the metric.


Puller you will need.

http://www.shopsbt.com/mm5/merchant.mvc?Screen=PROD&Product_Code=80-107


You will see some detailed pics in my XP thread of the loctite on the crank.

http://www.seadooforum.com/showthread.php?56273-96-XP-Resto-Project-Clapped-out

 

[Charleston]

Interesting finding is my used boat was missing its bilge pump. Per the parts list this is P/N 278000643 and is just not made any more. You can find them used on ebay but I question that. Used bilge pumps? It looks like a replacement with all parts is made by Rule and it is red/white/blue. These come in all sorts of different GPM volumes. It looks like people have installed between 350 GPM and 500 GPM for this model that uses 12V/2.5AMP.

Originals seem to run near 40.00 but these Rule models are closer to 20.00.

Charleston

 

[IDoSeaDoo]

I've got a Rule in mine, I want to say it's the 500 but I'm not 100% on that. It's a small little guy, but works just fine.

 

[Charleston]

Awesome link Racerxxx. That flywheel puller worked like a charm. It was 20.00 and it came fast from them. I also played around with the Evapo-rust I saw on your thread. The new engine flywheel is yuck. My old one just needed a little love and looks new.

I am questioning this "Molykote 111" requirement. Checked a few threads on it. It would be for this crank seal. I did see this online:

http://www.waterfilterexperts.com/product.php?p=o-ring-silicone-lubricant-5.3-oz-tube_dow-corning_or-lubricant-lg&product=175809

What have you used in its replacement. This looks like something important to keep the seal "moist" so it doesn't crack. Feel free to throw me a few suggestions you have used with no issues.

BTW. Did also find this stuff on Amazon. Use search words "dow 111" and you can find a tube including shipping for under 20.00.

Charleston.

 

[Charleston]

Real need for technical knowledge here.

My new motor/magneto and my OLD motor/magneto have a unqiue and not-listed part for the oil pump. Per the part prints, I should have a part called the "Shaft Oil Pump #23 P/N 420837392". Neither had this part. Both had some type of broken black cylinder in it. See these pics.



The per-design part should drive the oil pump from the crank shaft. I can only assume that this system is now BYPASSED by the use of this part. Which makes sense since my own oil feed system was bypassed other than the bottom feeds to engine. Can anyone confirm that this is what I found here? There doesn't seems to be any direct feed to this pump otherwise. Is this oil pump connected to the magneto housing ONLY for the fuel/oil mixture then?

On a side note...for the 18.00. I ended up buying the Dow Molykote 111 from Amazon. No real repair access available for seal replacement other than pulling out the motor again so I am just doing what is per spec.

Thank you again.
Charleston.