787 Engine Teardown

[mikidymac]

I have never had any luck with the impact wrench and it would be hard on the splines.
Even on ones I never thought would pop I pull the engine and lay it on it's side.
Then heat the crap out of the PTO and with the impeller tool and a 2' craftsman breaker bar I put hand tension on it then give it a sharp hard hit with a small hand sledge. IF it doesn't pop with a few hits then more heat. I repeat this process over and over and they all come off. Heat Heat Heat. Then replace the seals and o-rings with new.

 

[jimmaki]

OK, I understand about removing the flywheels to replace the seals, but if I pull the engine can I split the crankcase with both flywheels still attached? Reason I'm asking is I need to know which bearing(s) have gone bad in order to decide how to proceed. My options, depending on what I find are: 1)replace end bearing and seals, 2)replace crank assembly with a rebuilt, 3)buy a whole SBT engine with a 2 year warranty.

The top end looks so so. While it compression checked 158 psi MAG/160 psi PTO the MAG piston had some scuffing on the exhaust side and the lower ring was locked in the groove on the exhaust side. Since it never ran lean to my knowledge, I'm guessing the front rv seal was ruined when the cage in the bearing next to it decided to fall apart. There's ton of carbon on the piston skirt and the locked lower ring is freeing up with carb clearner so it's not hammered stuck, just gummed up. While I don't see any cage fragments or signs of metal going through the top end, I can hear balls dropping in their race when I slowly rotate the crank. Also, there's a lot of oil in the mag side of the engine whereas the PTO side is whistle clean.

This is more a learning process than seeing how fast or cheap I can get back on the water. If all the bearing races are pitted then I'll know I need to "winterize" even though here in Florida we don't recognize that season. Winter here for SeaDoos is just the owner not using it for months or years but not knowing that's the case on the last ride of any given day.

 

[onlyadoo]

It won't split with the front flywheel on. Gotta use a heat gun and a puller. The pto flywheel put the engine back together, use a rag and your spline tool wth a breaker bar.

 

[jimmaki]

It won't split with the front flywheel on. Gotta use a heat gun and a puller. The pto flywheel put the engine back together, use a rag and your spline tool wth a breaker bar.

Got the heat gun and puller, now all I gotta do is get the mag cover off and the big nut. I have all the mag cover bolts out but the cover doesn't want to let loose. Still working on the back flywheel with the spline tool, breaker bar, steel pipe, MAP torch, sledge hammer and a lot of cursing.

 

[jimmaki]

I have never had any luck with the impact wrench and it would be hard on the splines.
Even on ones I never thought would pop I pull the engine and lay it on it's side.
Then heat the crap out of the PTO and with the impeller tool and a 2' craftsman breaker bar I put hand tension on it then give it a sharp hard hit with a small hand sledge. IF it doesn't pop with a few hits then more heat. I repeat this process over and over and they all come off. Heat Heat Heat. Then replace the seals and o-rings with new.

It's possible the rope I'm using is too soft and compressible. After it contacts the head and stops rotation, my breaker bar can still go another 30*s or so, admittedly with the force of a 4' long 1-1/2"dia 1/4" wall steel pipe handle extension. With the engine in the ski I can start the breaker bar at one wall of the hull opening and pretty much get it to touch the oppostie wall.

I only have a 18" breaker bar which I've tried using with and without a pipe and hitting with a small sledge but I feel like I'm beating on a rubber wall. Does that make sense? I think if it's the rubber motor mounts giving plus the rope compressing.

Will try to get the engine out and see if I can get the PTO to glow. Looks like we're doing Sea World and Disneyworld this weekend so not much wrenching going on.

 

[mikidymac]

Get that engine out.

For the MAG cover remove all the bolts and you will see two slots for prying the cover off. Just work it from side to side and it will slowly work it's way off.
Use and impact to remove the Flywheel nut and on the puller. It will pop the flywheel off like nothing.

On the PTO you don't want it "red hot". Just heat it and smack then heat some more and smack. IT will come off. Also the rope will compress, that is why you keep constant pressure on the breaker bar when you hit it. I typically will have a friend hold the block down on it's side, use my foot to hold strong pressure on the breaker bar and then hit with the hammer.

If you need a break, take one and have a beer then go after it and heat again.

 

[jimmaki]

Get that engine out.

For the MAG cover remove all the bolts and you will see two slots for prying the cover off. Just work it from side to side and it will slowly work it's way off.
Use and impact to remove the Flywheel nut and on the puller. It will pop the flywheel off like nothing.

On the PTO you don't want it "red hot". Just heat it and smack then heat some more and smack. IT will come off. Also the rope will compress, that is why you keep constant pressure on the breaker bar when you hit it. I typically will have a friend hold the block down on it's side, use my foot to hold strong pressure on the breaker bar and then hit with the hammer.

If you need a break, take one and have a beer then go after it and heat again.

OK ... engine coming out. If a strong/heavy enough friend isn't available when I do this I'll bolt it to something. I don't want to have to worry about busting out an engine mount. I think on solid footing rather than rubber, the PTO should yield to a good whack.

Wow, what a buzz, I thought you said, "If you need a break, take one and have a beer then go after it and have eight again" I did that twice.....

 

[jimmaki]

Get that engine out.

It's out! Betcha thought you'd never see this...

 

[jimmaki]

Starter leads disconnected, engine raised all the way ... and ... and ... hmmm, this doesn't look quite right... anyone know where I can get a lower crankcase?

 

[jimmaki]

Not too happy with SBT special tools right now. Bolted the engine down and tried to unwind the PTO flywheel with a long bar and short hammer. Snapped the splined tool right below the hex.

Decided to redirect my frustration by working on the other end of the engine by getting off the MAG flywheel, got the mag cover off finally (wish they had run the o-ring around the OUTSIDE of the locating pins so they wouldn't corrode) but the good news is the rest of the inside was whistle clean. Got the nut off without any drama with an impact wrench. But, the SBT universal tool screws are too short and the wrong size thead to reach/screw into the flywheel. The tool label says, "Universal Flywheel Puller Except Kaw 900/1100/1200" I'll order the oem tool.

batting 0 for 2.

Still not sure what to do about the CB gear break out which ventilated both halves of the crankcase. Wonder if it can be welded or if this engine is a total basket case. Considering I never ran it lean or without oil, I'm surprised it ate itself up. I haven't gotten the case split yet so I'm just guessing, but I think the CB bearing cage went west and ball fell out of the race and got caught between the gear and the case and zipped a nice ball width slot in both case halves.

 

[mikidymac]

OUCH!

I am glad you finally pulled it but so sorry for your loss.

Depending on what you decide I am sure someone here like Minnetonka can hook you up with cases. I would not try to patch those.

As far as the SBT tools I will probably get yelled at again here for speaking my mind about SBT but you get what you pay for. I think the one I have might be from Motion-Pro.

Also be careful with the "universal" pullers because if you thread the bolts in too far you can damage the stator on some models.

 

[racerxxx]

Here's the puller you need. Don't buy universal crap it never works out. The 787 has threads on the flywheel that you pull on, and no need to remove the MAG from the flywheel either.


http://www.shopsbt.com/jetski_repair_tools/sea-doo-flywheel-puller-xp-gtx-spx-challenger-lrv.html

That case is junk, 787 cases can be had cheap.

 

[jimmaki]

OUCH!

I am glad you finally pulled it but so sorry for your loss.

Depending on what you decide I am sure someone here like Minnetonka can hook you up with cases. I would not try to patch those.

As far as the SBT tools I will probably get yelled at again here for speaking my mind about SBT but you get what you pay for. I think the one I have might be from Motion-Pro.

Also be careful with the "universal" pullers because if you thread the bolts in too far you can damage the stator on some models.

Thanks, I think the stator is on the inside of the cover ... so no worries there but not only are the bolts that came with the puller the wrong size, none of the holes in the plate line up with the holes in the flywheel. I even went and got some M6 x 50mm bolts but nothing lined up. Dead in the water until right puller arrives. Although I did get the starter off and loosened all the bolts holding the case together ... except for the one bolt up front that I couldn't get to with the bell housing still on.

 

[jimmaki]

Here's the puller you need. Don't buy universal crap it never works out. The 787 has threads on the flywheel that you pull on, and no need to remove the MAG from the flywheel either.


http://www.shopsbt.com/jetski_repair_tools/sea-doo-flywheel-puller-xp-gtx-spx-challenger-lrv.html

That case is junk, 787 cases can be had cheap.

Thanks, it's ordered... only cost me $200. But I got a free alignment tool and rv timing wheel and free shipping.

Where's the best place to get a case? How cheap?

 

[racerxxx]

Post a want add on the forum. Or eBay, just study the pics to make sure you're not buying junk.

Sent from my SGH-T889 using Tapatalk

 

[jimmaki]

Post a want add on the forum. Or eBay, just study the pics to make sure you're not buying junk.

Sent from my SGH-T889 using Tapatalk

OK, speaking of buying junk .... came with the wrong size bolts (too big) and they were the wrong length (too short), and when I bought the right size bolts, none of the holes lined up so you end up with this mess and an unpulled flywheel. Lucky those M6's didn't break off in the flywheel.



What should I be looking for in the pics? (aside from gaping holes)

 

[mikidymac]

I would contact Nick AKA: Minnetonka4me
[MENTION=41828]Minnetonka4me[/MENTION]

 

[Minnetonka4me]

Yup I have some available in good shape.

 

[jimmaki]

Yup I have some available in good shape.

Great, I only need one (1998 SPX 787 carb) .... next step?

 

[jimmaki]

I would contact Nick AKA: Minnetonka4me
[MENTION=41828]Minnetonka4me[/MENTION]

Thanks ... nice to have a referral ... lot's of scary looking stuff on ebay.

 

[jimmaki]

OUCH!

I am glad you finally pulled it but so sorry for your loss.

As far as the SBT tools I will probably get yelled at again here for speaking my mind about SBT but you get what you pay for. I think the one I have might be from Motion-Pro.

Funny how we console the loss of a toy part like the passing of a loved family member.

Why would you get yelled at?

Having done very little engine work, and no seadoo engine work, I have very few special tools.

What has given me the biggest challenge so far are all the corroded fasteners and parts that just do not want to come out/apart. I could understand if the ski sunk and was full of water or sea water for an extended period of time, but it never has.

I know the experts here have developed the techniques and know when to be patient and let penetrating oil and or heat do it's thing. I'm learning. So far I have broken one head bolt, an RV cover bolt which I think was already broken (rusted across the entire diameter at the fracture line) and broke out the corners of two RV cover bolt holes due to corrosion expansion around the bolt. Fractured an aftermarket impeller tool trying to get the PTO flywheel off, and am waiting on the right puller to get the MAG flywheel off.

When I see this guy in the video completely disassemble the same engine in 20 minutes with only an 8" ratchet and no power or air tools, my biggest disbelief is how all my bolts took an act of congress to get out and none of his gave him any trouble at all.
If only it were that easy.

[video=youtube;Ark5WCF5snc]https://www.youtube.com/watch?v=Ark5WCF5snc[/video]

 

[jimmaki]

Yup I have some available in good shape.

I clicked on the links and ended up in image nirvana. Is there some way to search rather than opening each image from the thumbnails? I could not find any 1998 SPX stuff. What other years and models use the same parts? At this point mostly interested in 787 carbed engine parts, crankcase, RV cover for a 1998 SPX.

 

[jimmaki]

Post a want add on the forum. Or eBay, just study the pics to make sure you're not buying junk.

Sent from my SGH-T889 using Tapatalk

I've been studying pics on eBay but not sure what to look for. Here is one for $89 from dbcycleparts with a 99+% rating. It looks ok to me except where the bearings go it has shiney swipe marks like the bearing outer races were turning in the case. Aren't the bearing pinned so they can't rotate?

It looks like my case, but the seller describes it as "SEADOO 1996 96 GTX STOCK OEM CRANKCASE CASE ASSEMBLY 787 800 XP GSX CHALLENGER." Would it work on my 98 SPX?
It would be nice to have some kind of cross reference on what parts work with which model years.

 

[Ankeneyou]

All 787 carb engines will work in your ski. These were in many different skis/years. You can refer to the model reference here if you want the specific model/years.
http://www.seadoosource.com/seadoomodelreference.html

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[jimmaki]

All 787 carb engines will work in your ski. These were in many different skis/years. You can refer to the model reference here if you want the specific model/years.
http://www.seadoosource.com/seadoomodelreference.html

Sent from my SAMSUNG-SM-G900A using Tapatalk

Thanks, is the 787 the same as the 800? I see them listed interchangeably sometimes as "xxx parts for the 787/800". Some sites like the one I linked to at db cycle parts have compatibility deamons/calculators where you put in your year/model. I tried that on the 787 crankcase and got this when I put in my year model ski: