97 XP 787cc - Mods to plane faster?

[Quelin Zammit]

PLEASE HELP

So i recently bought a 97 SeaDoo XP, the 787cc 110bhp model, which has a hull like the XPL 951cc (can be seen in my display picture). It's the first model with the spring seat. (sorry to be so detailed but i want to make sure i get the right information for my ski). I love my baby

So my brother in law has a 96 SP with just 55hp, and when we drag race he just destroys me in the start, we do a hole shot and keep racing out of a local bay, i catch up to him and eventually get past him very easily once we both get to top speed and start getting out of the bay, we live on an island and it's only offshore riding, no lakes or rivers. My ski takes chop and waves much better than his.

So basically what i want it to be able to plane faster, which is the main reason he gets about 40-50feet on me in the first around 10 seconds, he literally flies off, it's like his ski is planed from the get go.

What bolt on mods can i get to plane faster? I don't really want to touch the engine as it's an immaculate ski and i don't really want to touch the engine unless i really have to.

PLEASE HELP AS I AM DESPERATE TO PLANE FASTER AND GET GOING QUICKER.

Any help is greatly appreciated guys.

Thanks

 

[soccerdad]

First Welcome!

Your ski should spank his assuming your motor is running well. Sounds like you have a bad cavitation problem. (your jet pump is sucking in air or fighting to grab hold of the water) First, check your wear ring for too much clearance. Also your carbon seal on the drive shaft could be warn and letting air in. Search this forum on wear ring replacement and the carbon seal. There are dozens of posts on how to check and replace them if needed.

 

[Krispy]

Soccer Dad is right on the money with his advice. Cavitation will cause this exact problem. It feels almost like it is "spinning out" in the automotive world.

I have the previous year XP and ended up noticing the effect of VTS (trim) recently on my launch. I was having problems on the other end of the spectrum however.

What about trimming up, to lift the bow quicker?

 

[Quelin Zammit]

To be honest, if i trim in dead middle, i noticed it planes faster, shouldn't it plane faster if i trim down rather than up? So it lifts the back and lowers the front thus planing quicker?

 

[SabrToothSqrl]

trim down will get you out faster, then trim it up as you get moving.

a 951 will move you quicker. your hull is heavier than his and rides on the last 12" of it, so you have to be physically moving faster to hold plane.

 

[Quelin Zammit]

I don't think so, i recently had 2 mountings break and the shaft came out, the mechanic replaced the mountings and said the shaft was not bent luckily, he would have noticed the wear rings and carbon seals right? What i am noticing is that, when i hit the throttle from a stand still the engine just revs up to hell and over revs like crazy, with the rev limiter kicking in, sort of like rrruuuuuummmm rum rum rum rum rum rum rum till finally it planes and the revs settle, kind of like the impeller won't be getting enough water, BUT when it was in i told the mechanic to open the fuel a bit since it was going off when on idle, opening the fuel a bit fixed the not able to idle properly problem, so i assumed the over revving is due to more fuel is the engine, does that even make sense?

Thanks for all your help!

 

[Quelin Zammit]

First Welcome!

Your ski should spank his assuming your motor is running well. Sounds like you have a bad cavitation problem. (your jet pump is sucking in air or fighting to grab hold of the water) First, check your wear ring for too much clearance. Also your carbon seal on the drive shaft could be warn and letting air in. Search this forum on wear ring replacement and the carbon seal. There are dozens of posts on how to check and replace them if needed.

I don't think so, i recently had 2 mountings break and the shaft came out, the mechanic replaced the mountings and said the shaft was not bent luckily, he would have noticed the wear rings and carbon seals right? What i am noticing is that, when i hit the throttle from a stand still the engine just revs up to hell and over revs like crazy, with the rev limiter kicking in, sort of like rrruuuuuummmm rum rum rum rum rum rum rum till finally it planes and the revs settle, kind of like the impeller won't be getting enough water, BUT when it was in i told the mechanic to open the fuel a bit since it was going off when on idle, opening the fuel a bit fixed the not able to idle properly problem, so i assumed the over revving is due to more fuel is the engine, does that even make sense?

Thanks for all your help!

 

[Quelin Zammit]

Soccer Dad is right on the money with his advice. Cavitation will cause this exact problem. It feels almost like it is "spinning out" in the automotive world.

I have the previous year XP and ended up noticing the effect of VTS (trim) recently on my launch. I was having problems on the other end of the spectrum however.

What about trimming up, to lift the bow quicker?

To be honest, if i trim in dead middle, i noticed it planes faster, shouldn't it plane faster if i trim down rather than up? So it lifts the back and lowers the front thus planing quicker?

 

[Strizzo]

at least a wear ring, possibly the usual 97 xp rubber o ring stainless ring retainer failure.

open the rear hatch, and look at the driveshaft. there is a stainless steel piece on the shaft and a grey carbon seal attached to the hull with a rubber boot. see if you can slide the stainless ring up and down the shaft. if you can, then the rubber o ring that usually keeps the stainless ring pressed against the carbon seal has failed. you'll need one of these if your carbon seal ring is in good shape. http://www.parkeryamaha.com/seadoodriveshaftcclip272000135.aspx

 

[Coastiejoe]

If the gap is wider than the width of a dime the wear ring needs replaced.

 

[AdamXP800]

I don't think so, i recently had 2 mountings break and the shaft came out, the mechanic replaced the mountings and said the shaft was not bent luckily, he would have noticed the wear rings and carbon seals right? What i am noticing is that, when i hit the throttle from a stand still the engine just revs up to hell and over revs like crazy, with the rev limiter kicking in, sort of like rrruuuuuummmm rum rum rum rum rum rum rum till finally it planes and the revs settle, kind of like the impeller won't be getting enough water, BUT when it was in i told the mechanic to open the fuel a bit since it was going off when on idle, opening the fuel a bit fixed the not able to idle properly problem, so i assumed the over revving is due to more fuel is the engine, does that even make sense?

Thanks for all your help!

You are describing cavitation. Check wear ring, seal and impeller like stated above

 

[Strizzo]

This is normal
[video=youtube;yBtMYWJiBHg]http://www.youtube.com/watch?v=yBtMYWJiBHg[/video]

 

[Strizzo]

this ski is cavitating
[video=youtube;xpXCApP6OUw]http://www.youtube.com/watch?v=xpXCApP6OUw[/video]

 

[Quelin Zammit]

Thanks for all your answers guys, so any diy guide on how i can do this? i'm pretty new at all this, and is it something hard to do?

Thanks

 

[soccerdad]

As I noted, just use the forum search bar and look for wear ring or cavitation. There are hundreds of posts on it here. Also youtube has videos on how to change a wear ring. It is really easy to check for a worn ring. Put a flashlight in the intake grate pointing at the impeller. Then from the jet exhaust end look in there and see how much light you can see. The gap around the impeller to the wear ring should be less than the thickness of a dime. Take a picture or two of the wear ring gap and carbon seal. Post them. We can likely see the issue. Trust us, this is VERY common. A mechanic often just does what you ask him and does not suggest other fixes. The work is easy.

 

[Krispy]

To be honest, if i trim in dead middle, i noticed it planes faster, shouldn't it plane faster if i trim down rather than up? So it lifts the back and lowers the front thus planing quicker?

Yep, my method is trim down until up on plane then trim up for speed.

The problem comes when I am trimmed up and try to launch. I literally put the bow in the air and the pump comes unhooked.

I was thinking you couldn't lift the bow out of the water quick enough, hence I suggested trim up.

 

[Quelin Zammit]

As I noted, just use the forum search bar and look for wear ring or cavitation. There are hundreds of posts on it here. Also youtube has videos on how to change a wear ring. It is really easy to check for a worn ring. Put a flashlight in the intake grate pointing at the impeller. Then from the jet exhaust end look in there and see how much light you can see. The gap around the impeller to the wear ring should be less than the thickness of a dime. Take a picture or two of the wear ring gap and carbon seal. Post them. We can likely see the issue. Trust us, this is VERY common. A mechanic often just does what you ask him and does not suggest other fixes. The work is easy.

I'm really new to all this and not so good with computers, can you please give me some sort of link to this diy guide of how i can fix this? Thanks a million!

 

[Spimothy Leary]

ps... after you follow the advice, you will likely see improvement, but in general the 97 xp is a dog, although it should still beat the 55 hp models.

If you feel a bit overwhelmed with tackling this project, take it to a shop or find a qualified shade tree mechanic, and they can take care of you quick & easy, should be in and out quick, if he's not backed up with other customers you can expect same day or next day assuming he doesn't have to wait for parts.

 

[soccerdad]

http://www.seadooforum.com/forumdisplay.php?21-How-To-Tech-Articles This gets you to a bunch of how to things. A few down from the top is a how to on replacing the wear ring. A few lower is one for the carbon seal. Even if your wear ring is good, you should replace your pump oil. There is one for that also in that how to section.

https://www.youtube.com/results?search_query=replace+seadoo+wear+ring this will get you to a bunch of wear ring vids. Honesly, if you can find this forum, you should be able to find lots of information on this. Google is your friend.

 

[mikidymac]

ps... after you follow the advice, you will likely see improvement, but in general the 97 xp is a dog, although it should still beat the 55 hp models.

If you feel a bit overwhelmed with tackling this project, take it to a shop or find a qualified shade tree mechanic, and they can take care of you quick & easy, should be in and out quick, if he's not backed up with other customers you can expect same day or next day assuming he doesn't have to wait for parts.

All of this is true. I had a 1997 XP and loved it but although I think you do have a cavitation issue but a stock 1997 XP is a dog out of the hole. Even with yours fixed there is a good chance the SP will still pull you the first 30-40 feet. It is simple, yours is heavier and the reason yours turns so good is there is much more wetted area and drag on your hull than his. It takes more to get all of yours moving than his and the only cure is more power. I had the exact same situation as you, back in 1997 I had a brand new XP and my friend had a brand new SPI but the first time we raced he pulled me for the first 30' WTF I thought! I just bought the baddest seadoo ever made and got pulled by the SPI! A quick call to Group K confirmed the issue with this ski out of the hole so I boxed up the engine parts for a Sleeper kit. The next time out I acted like everything was normal and even my engine still looked stock so my friend had no idea. On the first run I smoked him and he was dumbfounded, I just told him I used 91 octane that day. Later I told him the truth and a few months later he sold the SPI and bought a 1997 XP.

 

[Quelin Zammit]

All of this is true. I had a 1997 XP and loved it but although I think you do have a cavitation issue but a stock 1997 XP is a dog out of the hole. Even with yours fixed there is a good chance the SP will still pull you the first 30-40 feet. It is simple, yours is heavier and the reason yours turns so good is there is much more wetted area and drag on your hull than his. It takes more to get all of yours moving than his and the only cure is more power. I had the exact same situation as you, back in 1997 I had a brand new XP and my friend had a brand new SPI but the first time we raced he pulled me for the first 30' WTF I thought! I just bought the baddest seadoo ever made and got pulled by the SPI! A quick call to Group K confirmed the issue with this ski out of the hole so I boxed up the engine parts for a Sleeper kit. The next time out I acted like everything was normal and even my engine still looked stock so my friend had no idea. On the first run I smoked him and he was dumbfounded, I just told him I used 91 octane that day. Later I told him the truth and a few months later he sold the SPI and bought a 1997 XP.

Please tell me more about this sleeper kit
Is there a way of buying it online and having my local mechanic fit everything in?
My cousin just got a 2002 GTX with the di 130hp engine, any idea if i can beat him in chop, since his is a 3 seater and surely heavier? Or will the extra 20hp make all the difference?

Thank all

 

[Strizzo]

Please tell me more about this sleeper kit
Is there a way of buying it online and having my local mechanic fit everything in?
My cousin just got a 2002 GTX with the di 130hp engine, any idea if i can beat him in chop, since his is a 3 seater and surely heavier? Or will the extra 20hp make all the difference?

Thank all

stock for stock, in chop the 3 seater will probably eat your lunch. the longer ski and higher weight is an advantage as it can plow through the waves and keeps the pump hooked up. on flat water, you might be even or slightly slower than the gtx.

 

[soccerdad]

On the chop the gtx will kill it. You could get a front loader grate to help keep the pump full but it will slow top end some. Read my smith mountain lake post I just posted. My gtx killed the gsx in chop. I have never been on your hull but I expect similar results.


Sent from my iPhone using Tapatalk

 

[Quelin Zammit]

On the chop the gtx will kill it. You could get a front loader grate to help keep the pump full but it will slow top end some. Read my smith mountain lake post I just posted. My gtx killed the gsx in chop. I have never been on your hull but I expect similar results.


Sent from my iPhone using Tapatalk

To be honest, i don't care much for top end speed as we live in Malta, it's an island in the middle of the Mediterranean Sea, so nothing but off-shore for us, no lakes nor rivers.
Can you recommend a good front loader grate that you mentioned?
Maybe a good impeller for out of the hole speed and which is good for chop?
Also, afriend of mine also told me to get a ride plate which should also help me in chop and accelerate faster, does that make any sense to you?

Thanks

 

[mikidymac]

The Group K Sleeper kit is a modification of your stock parts so you have to send them your head, cylinders, carbs and pump nozzle on the 1997 XP. Some people think it is over priced for what you get but they build endurance race skis so they know how to make power without decreasing reliability and have great customer service. Their mods do work from personal experience and the engine looks stock. The only thing that might be an issue for you is shipping costs.

You can read about them at www.groupk.com