Everything is (almost) working as it should. Now I am gun shy...Right or Wrong?

[Krispy]

This is a Seadoo XP question but bear with my history first.

Well, here is a bit of history, I have owned several Tigersharks in the past, and at one time I had a 1996 Tigershark Monte Carlo that made it through a couple of seasons after my first rebuild (my first personal engine build) when finally a piston ring hung on a port an caused a catastrophic failure.

I then rebuild that engine (again) and decided I would head down the path of more HP and more speed. I ended up shaving the head and adding flame arrestors, re-jetting carbs etc. And I was able to get another 3-5 mph out of it. After about 12 hours on that engine I smoked a PTO piston (hole in the center from detonation). I thought I had found the cause of the air leak and rebuilt using the same head, well about 6 hours on the new top end I failed the engine the same way. Finally on that engines 4th rebuild I took everything back to stock and rode it once only to prove it was functioning well (hopefully) and sold it.

Fast forward to the present.

I am the proud owner of a 96 XP, I can see that the whole design of the ski is much better than the old Tigershark I had, thanks to this forum I have been able to give it a health checkup, address some of the common problem areas, and get it running well.

Today marked the last of my sea trials, I was out riding with a coworker on his nice new Seadoo 130SE and we had a good time, for some reason I didn't feel comfortable really opening her up for long periods of time.

Today was the first day I really had her up to temperature, I noticed that it is *slightly* more difficult to start when the engine is hot. That is to say that it takes 2 seconds of holding the start button down rather than one as it does when the engine is cold.

I also noticed that when driving about half throttle ~4500 to 5000 rpm (40mph) if I give it ever so slightly more throttle the thing JUMPS out of the hole, It is like the pipe is really waking up at that RPM. I am not complaining, it just feels like the power progression is really non linear.

I brought it back to the dock after a good hour of riding during witch I had several no wake zones, and several on off cycles. It didn't leave me stranded it started every time I asked it to. However I am still a bit scared to take it out on a long haul full throttle down the lake. Not due to my riding skill, but more due to the fear of blowing my engine up and having my wife say "I told you so".

So I put the question to you guys:

Am I going to become less nervous about opening this thing up over the next few rides?

Am I being too paranoid?

I really want to go out and act like a crazy fool and have fun but I am afraid of the consequences of an unproven machine.

Thanks for any input.

 

[get_real]

I'm not that experienced yet but from the information you provided I see no reason to go easy on it. Sounds like you're still gunshy from the last ski. As long as it's not overheating and not running lean I see no reason not to run it hard with 2-3 minutes WOT runs with cool down periods inbetween.

 

[ocod]

Go out and ride like you stole it.

That jump in rpm is your 2 strokes power band and its where its the most happy.

Some beat on theres others don't. You have to get a feel for your ski and know when its not happy.
Make WOT pulls but don't hold it for very long w/o feathering the throttle some.
Just enough to hear engine isn't screaming at you at 7k rpms
:drool5:


Be prepared for break downs simple or not.
Most common are fouled plugs(extended no wake areas).
Then is running out of fuel b/c you have no working gauges.

If its mechanical theres nothing you can do but get towed in. Thats why you never ride alone........................

 

[manolocross]

There is only one way to find out. Go for it! As far as it jumping hp at about 5000 rpm you can adjust that by adjusting the rave valves. What your felling is the raves opening up and bang we got 110 hp!!! You can back out the red adjusters to flush with top... By the way when was the last time you cleaned them up???

 

[Krispy]

Raves were cleaned this week actually, with the gaskets replaced at the same time.

Any reason it would be more difficult to start when it is hot?

 

[ocod]

Raves were cleaned this week actually, with the gaskets replaced at the same time.

Any reason it would be more difficult to start when it is hot?

I think its usuallly from N/S leaking in the carbs.

 

[Dr Honda]

Raves were cleaned this week actually, with the gaskets replaced at the same time.

Any reason it would be more difficult to start when it is hot?

I think its usuallly from N/S leaking in the carbs.

He's right... but your ski isn't "Hard to start". From your post above... you said it's like 2 seconds more???? That's fine. If you said you have to hold the throttle wide open, and crank for 20 seconds... I'd say you have a prob. When the engien is hot... fuel will boil off... and the air in the bilge isn't clean... so it will normally take a few seconds of cranking.


Here's the real question... regardless if it's instant, or after 4~5 seconds... does it start clean, or does it sputter, and cough until you clear it out?



Second... I'm always worried about a new ski. It's normal. But, it sounds like you've been riding it for a while, and it's running well. My last test for that ski, would be to put in fresh spark plugs, and go for a hard ride. Then... check the plugs. If they are brown to black... you are good to go.


Lastly... your old tigershark was a product of lack of knowledge. The first failure could have been avoided if you beveled the ports properly. The seconds melt down was because you shaved the head improperly. (The squashband needs re-cut) The melted hole was from detonation. So... 1) wrong cut on the head 2) Too much static compression 3) Too much timing for the fuel 4) lean mixture. It could have been an air leak... but it was probably just improperly tuned. (FYI... the PTO cyl normally needs more fuel than the MAG cyl because the crank will twist under a load) When you mod... you HAVE to know how to tune.


OK... I wasn't bashing or anything... but there is more to making power on high output 2-stokes than people realize.


Anyway... leave your XP stock... feed it good synthetic API-TC oil... and have fun.



Oh... almost forgot... that "Jump" in power is your RAVE valves opening. Very normal on the 800 rotax engine. (and a good sign that they are functioning properly)

 

[Krispy]

He's right... but your ski isn't "Hard to start". From your post above... you said it's like 2 seconds more???? That's fine. If you said you have to hold the throttle wide open, and crank for 20 seconds... I'd say you have a prob. When the engien is hot... fuel will boil off... and the air in the bilge isn't clean... so it will normally take a few seconds of cranking.


Here's the real question... regardless if it's instant, or after 4~5 seconds... does it start clean, or does it sputter, and cough until you clear it out?



Second... I'm always worried about a new ski. It's normal. But, it sounds like you've been riding it for a while, and it's running well. My last test for that ski, would be to put in fresh spark plugs, and go for a hard ride. Then... check the plugs. If they are brown to black... you are good to go.


Lastly... your old tigershark was a product of lack of knowledge. The first failure could have been avoided if you beveled the ports properly. The seconds melt down was because you shaved the head improperly. (The squashband needs re-cut) The melted hole was from detonation. So... 1) wrong cut on the head 2) Too much static compression 3) Too much timing for the fuel 4) lean mixture. It could have been an air leak... but it was probably just improperly tuned. (FYI... the PTO cyl normally needs more fuel than the MAG cyl because the crank will twist under a load) When you mod... you HAVE to know how to tune.


OK... I wasn't bashing or anything... but there is more to making power on high output 2-stokes than people realize.


Anyway... leave your XP stock... feed it good synthetic API-TC oil... and have fun.



Oh... almost forgot... that "Jump" in power is your RAVE valves opening. Very normal on the 800 rotax engine. (and a good sign that they are functioning properly)

Thanks for your input,

There was only one true hard to start during my ride yesterday an it was after shutting it off while coasting on the trailer, I had to try to get it to start, once started it pulled the rest of the way on the trailer fine.

As for your engine diagnosis on the Tigershark, yes and no.

The ports probably weren't chamfered enough, deburred? yes, a true 45? no. I realized that my mom and pop machine shop wasn't up to the task so I got my next set of jugs from SBT.

As for tuning the Tigershark, I really thought I had it down, you should have seen my box of jets. I still have pictures of all the plugs from my full throttle plug chops. It was running well with no signs of lean plugs. Squish was measured with solder and calipers. It all went sour after an especially long WOT run trying to out run a fast approaching summer storm. I even suspected that the crank may have been out of phase. On that tear down I checked that bdc and tdc occurred at the same time (on the separate pistons) with a dial gauge. Looking back on it I could see how the rear piston could be more advanced under load.

Back to the XP,

I agree I should do some plug chops and see how things look. On my Tigershark it was a simple task to change plugs on water. I could simply step to the port side foot well, pull the seat and place in the other foot well and change the plugs.

This seadoo is much less stable than the shark, do y'all actually pull the plugs on the water? If so how?

I will take some good pics of my plugs shortly and get them posted for review.




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[Dr Honda]

Honestly... it doesn't need to be a true "Chop" since we are dealing with a stock engine. Just go out for a normal, 15 minute ride... and go back to the shore to check them. But try not to idle too long. The overall color will give you a general running indication of the engine.

 

[Krispy]

MAG

MAG again

PTO

PTO again

My amateur analysis says the mag is about right, PTO is a little rich.

Both carbs are at the same settings per the service manual. There is a slight load up of the carbs after extended running at idle, clears up after a couple of blips of the throttle.

What do y'all think?

 

[DSchmidt54]

Beautiful ! That glossy chocolate is exactly what you are looking for! as for doing the chops in the future.... if the water isnt too choppy... cut the engine... stand backwards on the ski with heels in the angled part at the front of the footwells.... pop the seat, balance it on the grab bar and use a stubby crescent wrench to loosen the plug.... ive done it alot on my GTX and a few times on my buddies GSX... but understantably the Xp is a little tippier..... you should be okay as long as you don't fumble a plug and let it fall under the block into the bilge lol. That is why i ALWAYS keep a set of spares in the purple container.

Long story short.... put them plugs back in , set your raves how you like (personally, i have mine 2 clicks in from flush, for a little better low end power..... then RIDE IT LIKE YOU STOLE IT!

lol have fun out there

 

[Seadoobuddy]

Krispy, this may help you to see the difference in the plugs. Post #2-#5. This is found in the "how to" section on the home page. there are about 60 articles there, if you only see a few then scroll down and click "from beginning"

http://www.seadooforum.com/showthread.php?4151-Snipes-Korner&p=115740#post115740

 

[Krispy]

Thanks for the help guys, that link is a good read. Thanks for sharing!

I think I have a 14 on the mag, and a 9 or 10 on the pto. Should I probably leave the carbs alone?

So the consensus is quit being gun shy and go for it?


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[Dr Honda]

To me... that's perfect !!!!


These are high output 2-strokes. I don't like to see them too light. If it was a dirtbike... I'd say you could lean it out... but on a ski (or even a snowmobile)... rich is safe.

Put the plugs back in... and go ride. :thumbsup:

 

[Spimothy Leary]

Respones are all spot on. Reminder to avoid excessively long wot runs. Ride it hard. Ride with another ski. Just dont peg it for stretches more than a minute or so.

 

[Krispy]

Ok, so I took my ski out this afternoon for a quick blast around the lake. It was a bit windy and the rain was coming in but it make for some good riding.

I was mainly trying to test my mirror squeak fix but I ended up spending a lot of time driving around.

First off with the squeaks and rattles quieted down I felt a lot more confident in my XP. I had a really great time and had only one minor issue related to my fuel gauge function, but that's another thread.

Thanks for the feedback and giving me the confidence to go out and beat on the ski a little bit. Man these things are fun!

 

[get_real]

Amen bro....took mine out tonight for a sunset run on smooth water and it was a blast! Still grinning.

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