Page 1 of 3 123 LastLast
Results 1 to 10 of 23
  1. #1

    Newbie Buying questions / Dilemma

    Hello all,

    I've rented various 'skis and am now looking to buy. I'm not a crazy fast rider but I want plenty of power to carry all passengers and always have more power than I need. The 130/150 Seadoos just don't have enough (the 150 is fine for top speed but not accelleration). So, I think I like the RXTX series - it's got plenty of space, 3 seats, the sound system, the accessible trunk. The Yamaha VXR has natural aspiration but the rest of its features are less interesting; it seems there isn't an '1800' Seadoo equivalent.

    So, here's my dilemma - to get more power, it seems I have to get a supercharger model - which adds a lot of extra maintenance cost. I could easily do 100 hours in a year, so that's an extra $6-8 dollars per hour for a new supercharger.

    100 hours doesn't seem like very much; why does a car last for tens of thousands of miles? Why 100 hours ? If I ride gently (I do) why wouldn't the supercharger last longer? How do I know when it needs changing ?

    I can't find a clear Seadoo model comparison chart (showing passengers, top speed, 0-30/0-60, engine).

    thanks,


  2. #2
    Xspook's Avatar
    Join Date
    Jan 2014
    Location
    Space coast, FL (Brevard County)
    Posts
    1,737
    +1
    354
    2017+ SeaDoo's don't require supercharger rebuilds.

    Good info here:
    https://www.steveninsales.com/2021-s...a-vs-kawasaki/

  3. #3
    Click avatar for tech links/info K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    45,641
    +1
    2,596
    The every-100-hours supercharger rebuild schedule was for the early/original generation of Seadoo supercharged engines.

    A few model years later that was revised to every 200 hours or two years IIRC.

    The current Seadoo supercharger design does not have a scheduled rebuild interval. You run it until it wears out, which may not occur for a long time.

    There are several factors that may affect supercharger clutch life, but an important factor is how often you would be riding in water rough enough to cause the jet pump to bounce out and then drop back into the water as you cross the waves. When the jet pump unhooks the engine RPM spikes upwards. When the hull reconnects with the water the engine RPM suddenly decreases as the water load through the jet pump resumes. The sudden RPM changes cause the supercharger clutch to momentarily slip, which creates a tiny amount of incremental wear. Accumulated over hundreds of running hours eventually the clutch wears enough to become ‘worn; and unable to provide full boost and engine power.


    A PWC is very different from an automobile. The engine in a PWC spends a large portion of the running time at or above the mid-point of the RPM band and often well into the upper half of the power range.

    Here is my own 350 running hour engine RPM report (we have two Yamaha SVHO in GP1800 hulls, not a Seadoo).

    We do a lot of distance cruising on plane at 40-60mph speeds.

    The low RPM accumulation is mostly idling and poking around at slow speeds waiting near launch ramps, slow speed zones in harbours, and hovering in open water talking with other nearby riders in our group.



    This is very different from a car engine that rarely spends more than a few seconds at a time in the upper half of the power band.

    BTW, the Yamaha SVHO engine does not have any scheduled supercharger maintenance intervals. Neither does the supercharger clutch, which differs from Seadoo in that the clutch is separate from the actual supercharger. The SVHO clutch does eventually wear, and replacement takes a couple of hours. I replaced one at 222 hours and the other is still original at 350 hours.

    Yamaha recently revised the sprag clutch design and the newer clutch should presumably last even longer with the type of riding we do.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	8151EEFF-A35B-49D8-9403-12B0EE5ADB13.jpg 
Views:	102 
Size:	34.7 KB 
ID:	479639  

  4. +1 by:


  5. #4
    Quote Originally Posted by Xspook View Post
    2017+ SeaDoo's don't require supercharger rebuilds.

    Good info here:
    https://www.steveninsales.com/2021-s...a-vs-kawasaki/
    Thanks; yes, I saw that page last week which is where I got the '100 hours' from, though I mis-typed it - it's actually 2 hours, but I think Seadoo calling their SC "maintenance free" is a bit misleading or at least disingenuous if what they mean is that, you can't repair the worn parts, you have to throw the whole thing out and spend $2500 every time it wears out.

  6. #5
    Thanks again K447. I mis-typed the 100 hours, I meant 200, and as per my reply above to the other member, "maintenance free" shouldn't mean it still wears out but you have to throw the whole thing in the trash and spend $2500 to replace it when it sounds like only the clutch might have worn out...sounds like a way to make more money, but whatever

    The info you've given (you're very generous, thank you!) about WHY it's different to a car and how I might cause more/less wear is really useful. Also, your hours to wear is useful (222/350 - I guess you calmed down as you got older ) Maybe coming off the throttle when you hit a wave might reduce wear, but you'll lose speed. I will be riding the Atlantic so it will be rough at times though I don't love the bouncing as much as some do (I love my spine more!). That graph/report - is that standard data one can download off the Seadoos or is it some fancy add-on?

    How did you know it was time to replace your SC and was it a slow degradation or a sudden one?

  7. #6
    Click avatar for tech links/info K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    45,641
    +1
    2,596
    http://greenhulk.net/forums/showthre...=1#post3063615
    Quote Originally Posted by LongIslandBrit View Post
    Thanks again K447. I mis-typed the 100 hours, I meant 200, and as per my reply above to the other member, "maintenance free" shouldn't mean it still wears out but you have to throw the whole thing in the trash and spend $2500 to replace it when it sounds like only the clutch might have worn out...sounds like a way to make more money, but whatever

    … Maybe coming off the throttle when you hit a wave might reduce wear, but you'll lose speed. I will be riding the Atlantic so it will be rough at times though I don't love the bouncing as much as some do (I love my spine more!).

    That graph/report - is that standard data one can download off the Seadoos or is it some fancy add-on?

    How did you know it was time to replace your SC and was it a slow degradation or a sudden one?
    Maintenance free does NOT mean it will not wear out.
    It means the manufacturer has made no specific provisions for the end user to service or repair the thing when it does wear out.

    Whether that maintenance-free thing can be fixed/serviced is up to the end user and/or the aftermarket to figure out.

    Apparently the current maintenance-free Seadoo superchargers can be rebuilt with aftermarket bearings and clutch washers. See the posts by Green Hulk himself on the Seadoo performance forums, and the supercharger rebuild service offered through the GH online performance store.

    The clutch design used in the Seadoo supercharger is entirely different from Yamaha.

    Yamaha uses a sprag clutch design whereby the supercharger wheel can spin faster that the engine is currently driving the supercharger. This is known as an over-running clutch. A sudden decrease in engine RPM does not require or attempt to force the supercharger wheel to also slow down in the same instant. The wheel can coast down until it again matches the current operating RPM of the engine. The sprags inside the clutch reengage when the RPM match and the SVHO engine again drives the supercharger wheel.

    The Yamaha clutch does not spin at supercharger RPM. There are intermediate gears that step up the RPM between the engine crank and the supercharger. The sprag clutch assembly is driven at engine RPM.

    Yamaha SVHO supercharger clutch and idler intermediate gears can be seen on left side of this photo.




    Seadoo supercharger uses a stack of special washers packed together with a specific torque/tension applied. These washers are directly behind the actual supercharger wheel and ride on the same shaft.

    Click image for larger version. 

Name:	DSC00637.jpg 
Views:	8 
Size:	75.8 KB 
ID:	479643

    The result is that the Seadoo clutch washers will not slip until a specific torque threshold is reached. In normal riding on smooth water there is no slip at all. The clutch transfers engine power to the supercharger wheel and it spins up. At maximum engine rpm the supercharger shaft and that clutch assembly is turning several tens of thousands of RPM.

    If there is a sudden change in engine RPM (such as when the jet pump re-enters the water after you bounce off a wave) the supercharger wheel inertia does not allow it to suddenly decelerate as quickly as the engine (which is directly coupled to the impeller). So the supercharger clutch slips, braking the supercharger’s rotational momentum. That slippage creates a tiny amount of incremental wear. Eventually the torque needed to cause the worn clutch washers to slip becomes less than the torque needed to power the supercharger wheel at WOT and the rider notices reduced engine power.

  8. #7
    Click avatar for tech links/info K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    45,641
    +1
    2,596
    http://greenhulk.net/forums/attachment.php?attachmentid=479639&d=1634390487
    Quote Originally Posted by LongIslandBrit View Post
    … That graph/report - is that standard data one can download off the Seadoos or is it some fancy add-on?
    That graph comes from the CANDooPro diagnostics software. The same software can be used for Yamaha, Seadoo and others. I just have it enabled for Yamaha watercraft. The Yamaha ECU logs the RPM history into the bands shown in the chart.

    Apparently the CANDooPro RPM history chart for Seadoo is similar
    https://candoopro.com/index.php?main_page=page&id=7
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	2010gtx13.jpg 
Views:	91 
Size:	37.7 KB 
ID:	479649  

  9. #8
    Thanks; and how did you know it was time to service the SC/clutch?

  10. #9

    Join Date
    May 2007
    Location
    Minneapolis MN
    Posts
    1,368
    +1
    219
    I'm baiting the Yamaha lovers but the Sea-Doo supercharger clutch is FAR more reliable than Yamaha's. It is a simple stack of friction washers-very few moving parts. Get the ski that has the features that you like. I don't think you need the 300 HP version of the Sea-Doo-the 230 or 170 HP should work.

  11. #10
    Click avatar for tech links/info K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    45,641
    +1
    2,596
    Quote Originally Posted by LongIslandBrit View Post
    … how did you know it was time to service the SC/clutch?
    In my case maximum available engine power was reduced and began to vary, whenever the engine RPM was high enough to demand/deliver boost from the supercharger.

    Sometimes the initial power reduction is quite minimal and easily overlooked. Further running time will gradually increase the amount of power that is ‘not there’.

    Sometimes all or most of the supercharger boost just vanishes altogether and the engine now feels very sluggish. Less power than a comparable non-supercharged engine.

    Cruising at/under about 5000 RPM there is very little to no actual boost being provided by the supercharger. If it was slipping it would be hard to notice.

    Squeeze the throttle harder and the engine RPM increases, boost increases (well, it is supposed to) and engine power rises rapidly. If the amount of power starts to lag behind what is expected based on your experienced throttle squeeze, then the engine is ‘down on power’ for some reason.

    There is a range of possible reasons for the engine power to be less that expected at high throttle levels. One of those reasons is the supercharger clutch is slipping.

    There are other possible reasons, some of which are quite simple fixes and cost very little.
    A boost hose clamp letting go is one example.



    Other reasons for reduced power can be quite expensive, including internal engine damage.

Page 1 of 3 123 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Newbie buying first ski!
    By howorks in forum Yamaha PWC Performance (4-stroke)
    Replies: 9
    Last Post: 09-08-2016, 09:03 AM
  2. newbie buying two 2013 fx sho
    By nick8454 in forum Yamaha Open Discussion
    Replies: 19
    Last Post: 06-22-2013, 02:29 PM
  3. Newbie buying a ski, help him pick the right one
    By Jkjeeper06 in forum Yamaha PWC Performance (4-stroke)
    Replies: 7
    Last Post: 04-19-2013, 11:07 AM
  4. NEWBIE: Buying a speedster, what to look for...
    By imnothot02 in forum Sea Doo Sport Boats
    Replies: 0
    Last Post: 04-27-2008, 07:45 PM
  5. Replies: 2
    Last Post: 07-30-2007, 08:22 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •