2006 rxt

[Sea dog]

Hi everyone... I have a small problem I think... Was out riding the ski on flat water the otherday and going about 55 mph on the dream-O-meter and the ski shut off.. wouldnt restart at all ! Got a tow from someone and brought it home.. the starter engages but the motor will not turn over, pulled the super charger.. you can hit the start button and see the starter flywhel spin and that is it... The pistons are not going up nor down at all... the machine has 66 hours on it.. Any ideas? Thanks for any input

 

[JCzGTX]

Hi everyone... I have a small problem I think... Was out riding the ski on flat water the otherday and going about 55 mph on the dream-O-meter and the ski shut off.. wouldnt restart at all ! Got a tow from someone and brought it home.. the starter engages but the motor will not turn over, pulled the super charger.. you can hit the start button and see the starter flywhel spin and that is it... The pistons are not going up nor down at all... the machine has 66 hours on it.. Any ideas? Thanks for any input

I am speaking from a car engine perspective... If the flywheel is spinning (which is attached to the crankshaft) and the pistons are not moving, something between the flywheel and crank broke. Obviously not the flywheel bolts or it would not stay on. I don't see how your crankshaft would just break though. And I don't see how all your connecting rods would break at once if the crankshaft is in fact turning with the flywheel.

Pistons not oving up and down, did you pull the heads or looking in the spark plug holes? If the pistons are not moving you will not get any compression. Do you have a gauge you can put on it and crank it over?

 

[Sea dog]

I can put my finger in were the supercharger goes... And I can turn the starter flywheel by hand...Looked on line and it looks like there is a keyway

 

[JCzGTX]

A broken key makes much more sense and is gonna be a lot better than any of the other possibilities. I hope it is something small like that. Been wanting to get one of those SC models, and I love my GTX....

 

[Sea dog]

Thanks for your help...nothing like the power of a supercharger

 

[Dennis]

There are 6 bolts that hold the flywheel to the crank. If they all broke, and I seriously doubt it, then the flywheel and rotor would fall onto the magneto and rear engine cover. Odds are the crankshaft broke......never seen that on a 4TEC yet.

 

[Michael211_2000]

Pull your spark plugs out and put a long screwdriver down in each spark plug hole while cranking... if the screwdriver doesn't come up out of the hole as you're turning the engine over, then you are most definitely going to have to pull the engine out and crack it open to see what's happened in there.

1st thing though is to confirm for a fact that the piston's aren't moving as the engine turns over. A long screwdriver in a spark plug hole would seem to be a safe way to verify this. Something good and long that can't fall into the cylinder and get lost in there at least (a long wooden dowel rod perhaps would work just as well... just make sure it's LONG).

I'll be interested to hear if your piston's really aren't moving or not now.

- Michael

 

[Michael211_2000]

...Odds are the crankshaft broke......never seen that on a 4TEC yet.

Dennis I recall reading someone else's post about a broken crankshaft in a 4TEC engine some time last summer, can't recall where I read it though (here or Green Hulk?). I do recall reading it though so it is not impossible just very unlikely. You'd think if the crank broke there'd be mechanical noise for at least a 2nd, it wouldn't just shut off. Weird!

- Michael

 

[Dennis]

Yea, you would think they would of heard a " bing, bang, and then a boom" at some point and time. Hopefully he reports back his findings. I'm curious. :cheers:

 

[Michael211_2000]

SeaDog, don't discount the possibility that the spark plugs just crapped out on you completely that last outting... my last run summer 2011 at 68 mph my spark plugs suddenly went south and I thought my engine had come apart inside it just seemed to die suddenly... I was barely able to get it back to the boat launch (luckily I wasn't very far away from the boat launch at the time the plugs died), the engine barely and I mean BARELY running with sudden surges and missing like crazy (no alarms or anything on the LCD display though). The spark plugs for whatever reason just stopped working right (though they were still partially working, just).

Also if you weren't turning the piston's up and down the starter would really spin the engine up fast and free, there'd be no compression for the starter to work against. I suspect in fact your pistons are still moving up and down when you crank it over it's just not firing... in which case try a brand new set of spark plugs in it.

- Michael

 

[Sea dog]

hi guys... .. i did put a long extension in the spark plug holes.. (one at a time)... it did not move at alluke:

 

[Michael211_2000]

Ah rats! You're going to have to pull the engine out and crack it open to find out what's happened then. I have no better ideas. :-(

- Michael

 

[Michael211_2000]

http://fiche.seadoowarehouse.com/seadooforums/showmodel.asp?Type=13&make=seadoopwc&A=116&B=3&modelid=2006 Sea Doo PWC RXT CRANKSHAFT W/ PISTONS AND BALANCED SHAFT

See link for exploded engine diagram of crankshaft and pistons... somehow the gear on the end must have broken loose? Weird!

- Michael

 

[Michael211_2000]

4TEC Crankshaft pics I found online for reference. I'm guessing the gear on the end is forged onto the crank?

- Michael

 

[Sea dog]

oh boy, i wish it was just a keyway

 

[JCzGTX]

That link doesn't work for me. Could just be ANOTHER iPad issue.... I have never seen a one piece crank/flywheel. It would either have a keyway or be pressed on I would ASSume.

I am really interested in this thread and to see what the issue is. I could see a keyway letting go all of sudden like that, but that crank just breaking at speed should have created a lot more noise and destruction.

If u pull the plugs can u turn the 4tecs by the driveshaft? Do the pistons move then? Just thinking of a way to check the other end of things if the flywheel is free spinning on the crank.

 

[Michael211_2000]

The link still works for me this morning, so I think it's just your iPad. In the parts explosion that gear on the end of the crankshaft isn't seperate from the crank which makes me think it's forged or welded to the crank, it's doesn't come as a seperate part. The 4TEC engine's don't use a flywheel like an automotive engine, it's just a couple of gears in the PTO side of the engine that drive the supercharger and waterpump and all. The gear you see on the end of the crankshaft in the pics I posted actually drives the balance shaft assembly (which runs parrallel to the crankshaft inside the engine), the starter gear bolts up to that gear with 6 bolts (you can see the threaded holes in the end of the gear in the pics). I don't think there's any keyway in there though, no key is shown in the exploded diagram link I posted. There is a "drive pin" shown but it appears to go in the output sleeve (which is where your jetpump driveshaft couples up inside the end of the motor).

No matter what it may be that's broken, I see no way to get access to any of it without pulling the engine out of the hull and splitting it open... that's gonna be 99% of the work right there, whether it be a gear problem or a crankshaft problem the time consuming part is getting to it then reassembling everything after you fix whatever it is that broke.

SeaDog, you could try pushing down on whichever piston is closest to the top of the cylinder and note whether the other pistons move and if the drive shaft to the jet pump turns... that would indicate if the crankshaft has broken in-two, or if the gear on the end has simply broken loose from the crank. If the jet pump driveshaft doesn't turn when a piston is pushed down then the crankshaft must have broken...

- Michael

 

[JCzGTX]

The link still works for me this morning, so I think it's just your iPad. In the parts explosion that gear on the end of the crankshaft isn't seperate from the crank which makes me think it's forged or welded to the crank, it's doesn't come as a seperate part. The 4TEC engine's don't use a flywheel like an automotive engine, it's just a couple of gears in the PTO side of the engine that drive the supercharger and waterpump and all. The gear you see on the end of the crankshaft in the pics I posted actually drives the balance shaft assembly (which runs parrallel to the crankshaft inside the engine), the starter gear bolts up to that gear with 6 bolts (you can see the threaded holes in the end of the gear in the pics). I don't think there's any keyway in there though, no key is shown in the exploded diagram link I posted. There is a "drive pin" shown but it appears to go in the output sleeve (which is where your jetpump driveshaft couples up inside the end of the motor).

No matter what it may be that's broken, I see no way to get access to any of it without pulling the engine out of the hull and splitting it open... that's gonna be 99% of the work right there, whether it be a gear problem or a crankshaft problem the time consuming part is getting to it then reassembling everything after you fix whatever it is that broke.

SeaDog, you could try pushing down on whichever piston is closest to the top of the cylinder and note whether the other pistons move and if the drive shaft to the jet pump turns... that would indicate if the crankshaft has broken in-two, or if the gear on the end has simply broken loose from the crank. If the jet pump driveshaft doesn't turn when a piston is pushed down then the crankshaft must have broken...

- Michael

Yeah that damn iPad man, doesn't work with flash websites either. Thinking about going back to a laptop.

I really hope you don't have big expensive broken parts. I think Michael has a great idea about pushing a piston down and even put long screwdrivers on the other pistons and see what is/is not moving. I could see the gear being welded on, but a single forged piece seems more expensive for the manufacturer.

I was not real sure how the starter on those was setup from the get go. So that gear shown does not directly contact the starter during starting?

It seems michael can take you down the right path. I will definitely stay tuned though and wish you the best of luck with it. I am looking for a slightly used 4tec GTX to add to the trailer so I am trying to learn now.

 

[Michael211_2000]

Mine's engine was mostly in pieces when I bought it (I bought it for a very low price though), so I had to learn how to reassemble the thing. That gear on the end may well be welded to the crank I cannot remember it's been 2 years since I had my hands on the part... but yes the gear on the end meshes with the balance shaft gear which turns the balance shaft (kinda functions as a harmonic dampner I think), the starter does not directly go to that gear on the end of the crankshaft another larger diameter gear bolts onto it and THAT gear drives the supercharger and is driven by the starter.

There's not alot more speculating we can do at this point though, the engine's gotta come out and the crankcase split open to find the actual point of failure. Fun fun fun I know!

- Michael

 

[Sea dog]

how hard would it be to pull the motor:willy_nilly:

 

[Michael211_2000]

Well, you have to pull the pump and driveshaft out, take the exhaust manifold off and out, take the intake manifold off and out, disconnect all the sensor leads from the intake and the engine (each lead plugs in to only 1 spot, so no need to label them), unbolt the engine from the motor mounts, then lift it out with an engine hoist or something (trust me you ain't lifting it out by hand it's still HEAVY!). Maybe 1 full weekend to get it out of the hull and onto a table.

Once out you'll have a bit of a job cracking it open still. I'm not sure if you should start with taking the PTO cover off the engine or splitting the crankcase open... you'll probably have to do both though. You'll want to get a full gasket kit, and new crankshaft mains stretch bolts (assuming you don't have to pull the head off... if you do pull the head off note that the head gasket and all stretch bolts must be replaced with new parts they aren't reusable!). Stretch bolts have a funny ringed look to them, they're used to hold the head on and the crankshaft mains and connecting rod bearings in place, and you throw them ALL away when you take them out. Reason being, they stretch a little when the engine heats up the 1st time, and if you retorque them down they're likely to break when they get stretched a 2nd time as the engine heats up and expands a little bit ergo you throw them away and go back with new ones.

The issue here is, given some time and effort and getting the SeaDoo Service Manual to read and study the instructions you can probably take it apart find and fix the problem and put it back together yourself but it's going to take you alot of time and some money, and you have to put it all back together RIGHT if you miss any 1 thing up the engine won't run right when it's back in the hull... so you have to be very careful and triple check everything you do. But you can probably do it yourself.

OTOH, if you take it to a dealership they're going to charge you probably almost as much as the watercraft is worth to take the engine out and apart and fix it and put it back together and into the hull again. The SeaDoo dealership wanted $4500 to fix the bent connecting rod in the engine of my '06 RXT for instance. The previous owner (who I bought it from with engine in pieces) still ended up having to pay the dealership ~$460 just for them taking the engine out of the hull and pulling the head off to diagnose it as having a bent connecting rod on piston #1.

I'm NOT an engine mechanic, but over the course of 3 weekends I fixed the engine with a good used connecting rod off Ebay (but new gaskets and stretch bolts) and re-assembled it and put it back in the hull hooked everything up put a new battery in and Wow! it fired right up and purred like a kitten! I made a 5pm mad-dash run to the lake to try it on the water and though there was only 30 minutes of daylight left I was able to confirm it ran well I was thrilled I'd only spent a few hundred in parts and tools and 3 weekends of my time to fix it... I'm a software developer, I've never worked on the internals of an engine before in my life but I got it back together and working without even knowning what it was supposed to look like fully assembled inside the hull. Not bad! Plus I now know how the engine comes apart and goes back together, what all is in there.

I tell you this so you'll know it's not rocket science, you can fix your own engine if you're willing to put the effort into it.

- Michael

 

[Michael211_2000]

Also just to add 1 more thing: you can't break what's already broken. That was my philosphy when I bought my RXT and trailed it home with the engine in cartons in the bed of my pickup truck. There wasn't much to lose by tring to fix and reassemble the engine myself, and I learned so much about it in the process it's spooky! LOL!

Of course, it ain't everybody's cup of tea though.

- Michael

 

[ski-d00]

don't pull the motor yet, the flywheel bolts are a common problem and there is a safety campaign on them to replace them with a stronger and better stretch bolt. just pull the mag housing, you don't need to pull the engine, fairly simple fix and normally does not do other damage.

 

[Michael211_2000]

Well I haven't heard or read anything about this common problem before in almost 2 years of reading posts on here... so it's news to me.

I can't see pulling the end off the engine with it still in the hull, that'd be harder than pulling the engine out and working on it on a table! Eeek! JMHO.

- Michael

 

[BMANN06]

Its not that hard to pull the mag cover off, with engine still in hull. Remove pump, steering/reverse bucket linkage, driveshaft. Then drain coolant and pump out oil, remove water pump, then support the port side engine use the hoist support thats on the head (rear). Remove the port side engine mount, then remove the mag housing fasteners, remove the electrical sensors (exhaust temp, cps, magneto). Pull mag off, service and reverse the process for re-installation.