787 Engine Teardown

[onlyadoo]

I would NOT use that grommet! Never had a problem with the eyelet. Only specialty tool is a degree wheel, to set the timing, and a torque wrench. SBT is right there in Clearwater. They offer a 1 yr warranty, but they mill the dome (squish gap) for warranty reasons. I think that's why people tend to go in other directions. I rebuild my own.

 

[onlyadoo]

If the rotary shaft needs replaced, There's a special tool to remove it too

 

[suke]

OHhhhhh, that lifting eye ... just went out to the garage and found it. Never noticed it for some reason.

Everytime I have to lift something with straps or what not, this video that I saw ages ago still haunts me.

I didn't use the lifting "eye" on my motor. Just wrapped straps around it and set it in.

 

[jimmaki]

I didn't use the lifting "eye" on my motor. Just wrapped straps around it and set it in.

Looks like a trailer winch with a ratchet wrench handle. I like your ingenuity! Is the winch strap pullied through U-bolts? Whatever works! I have to get up in the attic and find a truss to screw a support hook for a pulley or u-bolt or whatever.

 

[jimmaki]

View attachment 31436 I would NOT use that grommet! Never had a problem with the eyelet. Only specialty tool is a degree wheel, to set the timing, and a torque wrench. SBT is right there in Clearwater. They offer a 1 yr warranty, but they mill the dome (squish gap) for warranty reasons. I think that's why people tend to go in other directions. I rebuild my own.

By special tools I was thinking more about 30 ton presses, bearing and flywheel pullers, alignment tools, impeller tool, impeller shaft holding tool, pump housing puller, distance gauge, dial indicator, v-blocks .... etc.etc.etc. I'm not a machinist and don't even play one on tv. I just have to decide if I'm going to get a rebuilt engine, from whom, and for how much or sell the ski as is or trade it in on a something like a Spark, a plane or do the responsible thing and put the money in the college fund.

 

[jimmaki]

If the rotary shaft needs replaced, There's a special tool to remove it too

Didn't know that. Well, that settles it, I don't know enough about this to even try it. Given all the parts are about 18 years old, it may be time to retire the Doo. But I know you guys don't worry about things like that and just do whatever it takes to keep the old stuff running by throwing money at it. If I used it more, I might feel the same way but it usually just sits on it's lift by the dock baking in the FL sun and going bad, oxidizing, rusting and gumming up.

 

[jimmaki]

View attachment 31436 I would NOT use that grommet! Never had a problem with the eyelet. Only specialty tool is a degree wheel, to set the timing, and a torque wrench. SBT is right there in Clearwater. They offer a 1 yr warranty, but they mill the dome (squish gap) for warranty reasons. I think that's why people tend to go in other directions. I rebuild my own.

Just curious, do you happen to know why SBT mills the squish band? To lower the compression ratio and detune the motor so it lasts longer? If that's the case wouldn't it be easier to just use a thick gasket under the jugs? Or are most heads all dinged up from metal caught between the piston and squish band so they need to clean it up rather than using a good used or new head?

 

[suke]

Looks like a trailer winch with a ratchet wrench handle. I like your ingenuity! Is the winch strap pullied through U-bolts? Whatever works! I have to get up in the attic and find a truss to screw a support hook for a pulley or u-bolt or whatever.

YUP! I use that hand winch, minus the u-bolts in the ceiling, to pull my skis off the trailer and on to their stands. I was sitting around in the garage and trying to find a way to get my motor back into the hull by myself. Had a bunch of 3/8" lag bolts some 2x6's and u-bolts. Found some studs in the ceiling and came up with that setup. I hung from the u-bolts( I weigh 190lbs) and it held perfectly fine. Figured for sure it can hold my 80lb motor. HAH! Wrapped some ratchet straps around the motor and BINGO!

 

[racerxxx]

Just curious, do you happen to know why SBT mills the squish band? To lower the compression ratio and detune the motor so it lasts longer? If that's the case wouldn't it be easier to just use a thick gasket under the jugs? Or are most heads all dinged up from metal caught between the piston and squish band so they need to clean it up rather than using a good used or new head?

They do it for both reasons. Honestly I put two in for a guy in his challenger. I just replaced the base gasket on one of them cause it pushed out and was leaking water. They put way to much silicone on and I think that was part of the problem. When I pull the head off everything looked mint. If I wouldn't have known about them cutting the head, I never would have known. And I couldn't tell a damn but if difference in performance in the boat. If I were you and you want to keep the ski, just get an sbt and call it a day. And I NEVER recommend an engine rebuilder, but in your situation with such a low hour ski it would be a shame to break it down.

Sent from my SGH-T889 using Tapatalk

 

[onlyadoo]

Just curious, do you happen to know why SBT mills the squish band? To lower the compression ratio and detune the motor so it lasts longer? If that's the case wouldn't it be easier to just use a thick gasket under the jugs? Or are most heads all dinged up from metal caught between the piston and squish band so they need to clean it up rather than using a good used or new head?

If the squish gap is to close you can have detonation. Why they choose that route, I'm not sure

 

[onlyadoo]

Didn't know that. Well, that settles it, I don't know enough about this to even try it. Given all the parts are about 18 years old, it may be time to retire the Doo. But I know you guys don't worry about things like that and just do whatever it takes to keep the old stuff running by throwing money at it. If I used it more, I might feel the same way but it usually just sits on it's lift by the dock baking in the FL sun and going bad, oxidizing, rusting and gumming up.

I made one for cheap from home depot

 

[onlyadoo]

By special tools I was thinking more about 30 ton presses, bearing and flywheel pullers, alignment tools, impeller tool, impeller shaft holding tool, pump housing puller, distance gauge, dial indicator, v-blocks .... etc.etc.etc. I'm not a machinist and don't even play one on tv. I just have to decide if I'm going to get a rebuilt engine, from whom, and for how much or sell the ski as is or trade it in on a something like a Spark, a plane or do the responsible thing and put the money in the college fund.

I wouldn't try to rebuild the crank, all those tools are expensive. I got a rebuilt crank from a guy in Utah, he sells them for around $275 plus core. He used all WSM rods. Yon can get Top end kits for under $200. The impeller remover, rotary Shaft puller and degree wheel you can get all of them from SBT for under $100 total. If you splurge for the pop off pressure tool for $50, that's really enough to maintain and rebuild this ski for years. but if you don't want to mess with it, just get a rebuilt engine, rebuild the carbs, with new needles and seat ( if it's been awhile) and replace the grey fuel lines if you haven't already, make sure you clean the fuel selector too. You'll still need the degree wheel to set the timing.

 

[onlyadoo]

They do it for both reasons. Honestly I put two in for a guy in his challenger. I just replaced the base gasket on one of them cause it pushed out and was leaking water. They put way to much silicone on and I think that was part of the problem. When I pull the head off everything looked mint. If I wouldn't have known about them cutting the head, I never would have known. And I couldn't tell a damn but if difference in performance in the boat. If I were you and you want to keep the ski, just get an sbt and call it a day. And I NEVER recommend an engine rebuilder, but in your situation with such a low hour ski it would be a shame to break it down.

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I agree, sbt it, shipping shouldn't be bad for you. Depending on where you're at might just be able to just pick it up!

 

[jimmaki]

I agree, sbt it, shipping shouldn't be bad for you. Depending on where you're at might just be able to just pick it up!

Tampa is an hour from here, Clearwater maybe another 20 mins past Tampa over by the bay. It's a nice easy drive down I-4. I looked up the exact address and look what I found. Should I worry?

Either SBT is working out of a tent or they have or had a bug problem. Based on no cars in the parking lot when Google came by with their camera car, I guess SBT took the day off for fumigation. Darn roaches love seadoo oil.

 

[jimmaki]

I made one for cheap from home depotView attachment 31440

I'm sorry I don't know what that is. It looks like a cleanout cap in a piece of PVC. What does it do?

 

[jimmaki]

They do it for both reasons. Honestly I put two in for a guy in his challenger. I just replaced the base gasket on one of them cause it pushed out and was leaking water. They put way to much silicone on and I think that was part of the problem. When I pull the head off everything looked mint. If I wouldn't have known about them cutting the head, I never would have known. And I couldn't tell a damn but if difference in performance in the boat. If I were you and you want to keep the ski, just get an sbt and call it a day. And I NEVER recommend an engine rebuilder, but in your situation with such a low hour ski it would be a shame to break it down.

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Well, that's a meaningful recommendation from someone that knows these things. I was leaning towards SES since my engine is low hours and in good shape save one seal and bearing, so I liked the idea they would use my engine instead of some ventilated basket case welded up after sitting in a garage for years full of water. Nonetheless, it would be interesting to take the hour or so drive over to SBT and look at the operation. It will either make me feel better or make me run out screaming. If I like what I see I'll just order an engine.

 

[jimmaki]

I wouldn't try to rebuild the crank, all those tools are expensive. I got a rebuilt crank from a guy in Utah, he sells them for around $275 plus core. He used all WSM rods. Yon can get Top end kits for under $200. The impeller remover, rotary Shaft puller and degree wheel you can get all of them from SBT for under $100 total. If you splurge for the pop off pressure tool for $50, that's really enough to maintain and rebuild this ski for years. but if you don't want to mess with it, just get a rebuilt engine, rebuild the carbs, with new needles and seat ( if it's been awhile) and replace the grey fuel lines if you haven't already, make sure you clean the fuel selector too. You'll still need the degree wheel to set the timing.

Buying the tools is the easy but expensive part ... learning how to use them correctly is the dangerous and extremely expensive part.

 

[racerxxx]

If sbt is that close, your crazy not to go that route. I don't care what ses had to offer, if you have a warranty problem you're just over an hour away from getting it resolved vs a few weeks. Kinda a no brainer in my book.

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[jimmaki]

If sbt is that close, your crazy not to go that route. I don't care what ses had to offer, if you have a warranty problem you're just over an hour away from getting it resolved vs a few weeks. Kinda a no brainer in my book.

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I don't doubt it's a no brainer to an experienced wrencher like you, but to me taking out a warranteed engine and putting back in the replacement, even if I can be back here in two or three hours with it isn't something I would look forward to ... well, you see how long it took me to just take the top off this engine. I like the warranty I got with my Trane AC ... when it failed they came out, pulled the leaking unit, installed the new one, charged it with Freon, tested it and I didn't even need to put down my drink. But then, I'm not paying 5 grand for a pwc rebuilt.

The no fault warranty is about the same from SBT and SES, but SES uses more OEM parts or so they claim, so I don't care as much about the warranty compared to how much I care about the chances of the engine not needing the warranty in the first place, which the consensus around here seems to be, that OEM parts last longer.

At any rate, I'm not anti SBT. Maybe before school starts I'll take my daughter over to Busch Gardens in Tampa and swing by SBT either going or coming. I'm sure she'll be thrilled to see a noisy, oily machine shop.

 

[jimmaki]

I know it's a little late in the game to be asking this question, but is there a way to safely hold the crank from turning to remove the PTO and flywheel nut after the head and jugs have been removed without reinstalling them? I was thinking of maybe putting two pieces of pine straddling the connecting rod between the piston skirt and the top of the crankcase on the downstroke. But I wouldn't want to deform the piston skirt since it's not made to take that kind of force. Maybe a piece of soft wood between crank lobe and the crankcase?

 

[racerxxx]

Nope, Never had luck after the fact. It's the first thing I do. I remove the PTO spark plug and turn the engine over clockwise to TDC, then go past TDC a little bit, take about 6 foot of clothesline (the fatter stuff) and push it into the cylinder. The turn it CCW and with a 3' cheater bar on my breaker bar it usually pops free with no too much effort. If you want to try it another way, have fun beating your head against the wall. Oh, and I hop the engine is still in the hull if not you're gonna be chasing the engine around your shop floor.....don't ask me how I know.

 

[jimmaki]

Nope, Never had luck after the fact. It's the first thing I do. I remove the PTO spark plug and turn the engine over clockwise to TDC, then go past TDC a little bit, take about 6 foot of clothesline (the fatter stuff) and push it into the cylinder. The turn it CCW and with a 3' cheater bar on my breaker bar it usually pops free with no too much effort. If you want to try it another way, have fun beating your head against the wall. Oh, and I hop the engine is still in the hull if not you're gonna be chasing the engine around your shop floor.....don't ask me how I know.

Rats, I was hoping it was as simple as shoving a screwdriver into the starter motor hole into the flywheel gear or somesuch. Well, at least I asked before unbolting and hoisting the engine out. LOL, no I won't ask how you know.

Since I'll be putting the top end back together, how do I get all the crud out of the threads, both the holes in the crankcase and the bolt threads. Unless there's fantastic news when I open the bottom end I'll most likely be trading this engine in as a core so I just need to keep from turning a core into an anchor. I already broke one head bolt off during the teardown.

Logistics question ... to remove the flywheel in the boat, the mag cover has to come off first, right? So the front engine mount bolts to the cover. Will the rear mount be enough to hold the engine? I should probably take out the front mount bolt first and support the front of the engine somehow to take the shear load off the cover bolts? Without the front mount, the engine will "tilt" down in front. Should I take the pump off and pull the driveshaft so it doesn't bind/bend in the pto splines? Ordering some special tools today and wondering if I need that pump puller as well.

I should probably just button this thing up, yank it as a unit and send it to SBT for a core trade-in on a rebuilt engine and let them take the flywheels off, but I'm willing to put a little more in time and tools to learn what failed and hopefully figure out why.

 

[jimmaki]

Is there a trick to getting the bottom mag cover bolt out? It's too close to the fiberglass hump for the front engine mount to use a socket. And it's too close to the starboard fiberglass hump to get much more leverage than a 6" box or open end wrench on it. I may have to raise the front up about 3" to get a socket and long handle ratchet on it. Not sure that's kosher with the driveshaft in though.

The RV cover bolts are either torqued or corroded in solid. Can't budge them with a 16" ratchet. One head just about fell off, I think it was twisted off during factory assembly or sheared from vibration. There's rust across the whole fracture so it's been broken a while.

 

[jimmaki]

OK, got the front cover bolts off finally, yay!

Now to get the PTO off I assume the pump and drive shaft come off? Didn't have a 17mm deep socket for the pump nuts so ran out and got one. To remove the bailer lines the VTS housing that is in the way has to come off. Didn't have the giant socket to get the VTS nut off so ran out and got one. Everything loose and the pump even wiggles but it won't move back. Sprintz both ends of the driveshaft with Blaster, waited, tried again, no go. Took the c-clip off the top hat and loosen the clamps on both boots. Still no go. The pump is moving/rocking because of the foam rubber gasket allowing it to move forward, but it won't come back and off. I tried an L-angle pry bar but if I pry any harder I'll damage the pump or the gelcoat. I'm about ready to chain the pump to a tree and hook the 4 wheel drive to the trailer ....

Suggestions welcome before I pull the tree down.

[EDIT] Correction: I got the pump housing off by strapping it to a tree and pulling the SeaDoo with a lawn tractor. The pump popped right off. Once off I discovered what I thought was a foam rubber gasket was actually silicone sealant or adhesive. I probably would have never gotten the pump off just pulling on it with my arm strength alone.

 

[Spimothy Leary]

I didn't use the lifting "eye" on my motor. Just wrapped straps around it and set it in.

hmmm... after stealing your wall ratchet idea, I might have to steal this idea as well. It will come in handy a couple times a year, especially with the 951's, I don't find the 787's and smaller SD's to be much of a problem.