94 xp 657x just doesn't sound right...

[nsschwenk]

Hey guys...

I picked up a 94 xp 657x for free a couple months back and it had the nossle taken apart when I got it. So this weekend I was able to almost put it all back together but I wanted to test it first and flush all of the crude that was built up in it. I think it may have some "issues". Too good to be true right? ... a free xp?! I have uploaded a video of it running. Listen carefully... https://www.youtube.com/watch?v=JvQlAwMWp7Y

What I got out of this:

1. It sounds terrible... it sounds like something is loose in the engine. I inspected the pistons and they both have 120 psi compression. They move freely with no issues. Very little cylinder wall damage. I have a brand new extra top end too.. if it is needed. Could it be a rod bearing? or anything in the crank case? I took the PTO cuppler cover off to see if the drive shaft was warped. But I can't tell anything.

2. It smokes profusely when it runs; more than it should. It is pre mixed with the oil injection block off kit and mixed 50:1. Could it be leaking from the other two oil lines that lube the rotary gears in the crank case? I have a GTX 657x and it smokes 1/10 of what this xp does!

3. Throttling it, kills it. It can only idle. Giving it anything kills it. I'm sure this carb needs nursed back to health.

4. It vibrates terribly.

Let me know what you guys think. I would like to have some lead to where I need to investigate.

Thanks!

 

[TheMachin0]

sounds ruff 120psi is low if your gage is good you need rings the carbs look nice but prob need internals cleaned also the idle sounds slow 3000 out of the water. the smoke would be normal if the motor was fogged before it was stored last. maybe check your spark it almost sounds like your only getting one cylinder. carb adjustments maybe to find out the stock hi low settings and see were your at. that's all I can think of the fuel line look changed so your good ther

 

[nsschwenk]

Themachin0:
- I did a quick carb clean before I did this. They were actually spotless on the inside when I took it apart.
- I am using a Harbor Freight compression tester... so I heard they read lower.
- The fogging could be true.. the last owner said the engine had been winterized.
- I changed out a few of the fuel lines that I had on hand. It still has grey tempo fuel return lines.
- I installed new plugs. The plug wires are older that require the top of the plug cap to be removed.

 

[LouDoo]

The idle is way too low, it should idle about 3000rpm on the trailer, and about 1500rpm in the water. Yep and 120psi is way low, but maybe the rings haven't seated. It's really hard to diagnose a problem running on the trailer, how does she do in the water? Also you really need to run it with the air box and flame arrestor attached.

Lou

 

[nsschwenk]

After listening to my 95 gtx 657x... I do think themachin0 is right about it only firing on one cylinder. That could be why it is idling so slow as well. It could be why it is shaking badly too.

Loudoo:
- I usually run it with all of the air box junk but this is just for testing purposes and the carbs still need adjusting.
- I used my compression tester on a ski with a brand new sbt engine in perfect condition and the gauge still reads around ~ (120-130) psi (The Harbor Freight gauge sucks)
- I would love to run this thing on the lake but until I deem this ski as "lake safe" I'll take her out then.

 

[nsschwenk]

Wait.. could this ski just be running bad because it has been winterized? (Most people are to lazy to winterize ski's in my area so I'm not expecting it :lols

- I'm gonna try and run it some more tonight on the water hose to flush out more of the fogger oil and see if it will run better. How long does it take for it to wear off?
- I'll check to see if I am getting spark on both cylinders as well. Ill also run it with the flame assestor in it as well to see if it makes any difference.
- I'll take another compression test reading on both cylinders.

I uploaded some pics of the free ski the day I got it. It's been sitting for years and it deserves to live again!!

 

[LouDoo]

Just for shiz and giggles, try disconnecting the red wire from the voltage regulator/rectifier. If the problem clears replace the rectifier.

You don't have to run it on the lake, just leave it strapped on the trailer, you just need to put a load on the pump.

Lou

 

[pags1220]

http://m.youtube.com/watch?v=VRRqawWLV9I here's a video of mine running. Not sure if it helps but it sounds pretty healthy

 

[nsschwenk]

Lou:

If I unhook the rectifier... should I just try and run it for less than a min so it wont overcharge and defect my battery?

- I will put my fluke meter on the battery to see any changes. If the batter doesn't increase from the inital voltage before running, does it mean it is faulty? Unplugging the rectifier will cause the battery voltage to go up a lot?

 

[LouDoo]

If you disconnect the rectifier the stator will not charge the battery, it won't overcharge or damage the battery, if you're uncomfortable disconnecting the rectifier you can check the charging voltage at the battery, check and see if there is an AC component riding on the DC then you have a bad rectifier. I just suggested disconnecting the rectifier because it's easier and will give instant results.

Lou

 

[nsschwenk]

In the video... What is the raddling and clunky noise? It sounds to me something metallic to metallic hitting in the engine. Its like the piston is wobbling inside the cylinder or a rod bearing is shot.

 

[LouDoo]

It's most likely known as the "seadoo rattle", and is coming from the pump, there's about 1/8" play in the impeller shaft, the rattle will go away once the ski is under load in the water, this is one of the reasons I suggested taking it to the lake.

Lou

 

[nsschwenk]

I thought it could be the cone rattle, but I ruled it out sense my GTX 657x doesn't have that sound and it doesn't have the aftermarket cone assembly either.

 

[LouDoo]

I thought it could be the cone rattle, but I ruled it out sense my GTX 657x doesn't have that sound and it doesn't have the aftermarket cone assembly either.

Well you must have the only 2-stroke seadoo in existence that doesn't rattle. Since you have an argument for every suggestion I make, I'm going to back out of this thread and let others help you. Good luck.

Lou

 

[AdamXP800]

I haven't seen a doo yet that does not have the pump rattle.

 

[AdamXP800]

Unplugging the red wire is the EASIEST way to test your rectifier. I have done and seen it done hundreds of times with no negative effects. It sure won't over charge your battery

 

[nsschwenk]

Hey guys! Thanks for all of the suggestions so far. I took apart the mpem box and this is what I found. It looks like a mess :facepalm: I wanted to do the rectifier thingy you guys told me to do but it was already unhooked and when I tried hooking it up, it just started smoking and sparks were flying everwhere! :facepalm:



Update:
- I tried adjusting the idle screw... nothing happened at all adjusting it in either direction.
- I tried throttling it... nothing happened. At WOT, it would slowly die down the rpm's of the engine.
- I ran the engine at idle for 45 mins on the water hose and it still smokes badly and used a lot of fuel quickly.
- I re-did a compression test. 105 psi on PTO cylinder, 95 psi on MAG cylinder. I know its low. (I'm going install a new top end)
- I did however get the engine to rev up 1 time and it sounded amazing but it died right after.
- The trim doesn't work...
- There is a fuse missing from the MPEM box and a couple wires are not connected to anything at all...

Does anyone have a video or good pics on how to wire this mpem up correctly? I'm going to just completley re-do the carbs as they are all messed up.

Any Suggestions?

 

[pags1220]

If I were you I would go premium and or get the manual for this motor. 45 min on a hose in my opinion is about 40 min over doing it. You should have listened to loudoo as he is very helpful and full of knowledge. You should have about 150 psi in both cyl. I have a harbor freight gauge as well and mine reads 150 in both cyl. Rebuild your top end to manual specs. Rebuild your carbs with mikuni rebuild kits and purchase new needles and seats. Change every inch of fuel line if you have the old grey lines. Clean your fuel selector switch. Or replace it. Reset your carbs back to the factory settings. Get new plugs and change your cone oil. If you don't have the tools or knowledge on how to do these things. Take your ski to a local dealer and let them fix it before you make things worse. And most importantly. LISTEN TO THE PEOPLE WHO ARE TRYING TO HELP YOU.

 

[Luv2Camp]

I literally threw out my harbor freight gauge in my trash.... 120 on the gauge and when I bought a real gauge, it reads 141. Way low....

 

[pags1220]

Mine reads 150. Either I got lucky or I have even greater compression. Either way I'm satisfied lol

 

[nsschwenk]

Well maybe my gauge is incorrect or faulty because I tested a new ski engine and it read around 125 psi on the gauge

 

[nsschwenk]

I'm probably going to just do a complete overhaul myself and I can work out all of the bugs.. I just thought a quick fix could get it at least running and drivable to ride for 2 months and then overhaul everything during the off season. I have never rode an XP before. It doesn't look like it will turn out that way. At least I have two other ski's I can ride that are already overhauled and built to spec.

If I can find a R&D head, aftermarket pipe, re-jet the carbs, repaint it or put a nice wrap, I could make a nice race bike.

 

[TheMachin0]

Hey guys! Thanks for all of the suggestions so far. I took apart the mpem box and this is what I found. It looks like a mess :facepalm: I wanted to do the rectifier thingy you guys told me to do but it was already unhooked and when I tried hooking it up, it just started smoking and sparks were flying everwhere! :facepalm:

View attachment 25059View attachment 25060View attachment 25061View attachment 25062

Update:
- I tried adjusting the idle screw... nothing happened at all adjusting it in either direction.
- I tried throttling it... nothing happened. At WOT, it would slowly die down the rpm's of the engine.
- I ran the engine at idle for 45 mins on the water hose and it still smokes badly and used a lot of fuel quickly.
- I re-did a compression test. 105 psi on PTO cylinder, 95 psi on MAG cylinder. I know its low. (I'm going install a new top end)
- I did however get the engine to rev up 1 time and it sounded amazing but it died right after.
- The trim doesn't work...
- There is a fuse missing from the MPEM box and a couple wires are not connected to anything at all...

Does anyone have a video or good pics on how to wire this mpem up correctly? I'm going to just completley re-do the carbs as they are all messed up.

Any Suggestions?

I hope some one can help with the wiring if your going to do the pistons I would pull the trigger on them until you check the rv gear seals the may be rotted and the reason for so much smoke. as far as the comp gage mine also is crap I used my friends good one to check it his reads 167psi on both mine said 151psi on both reads 16 psi low but still a good tool.

 

[nsschwenk]

Yeah I figured it might be the RV or some sorta seal that could be leaking oil into the case. I thought it could of been the fogging oil when they winterized it before a long time ago, but that doesn't seem to be the case.

But overall... who ever had this ski before really messed everything up. It has a bunch of mix and match parts and cut and spliced wires. Because of all of this mess it is hard to convert it back to OEM specs without just replacing everything. This ski is in a lot worse shape than I thought.. but maybe that is why it was free?!

I would love to do some trouble shooting with some in water testing, as suggested by LouDoo. I wish I lived closer to a ramp access point and it didn't cost $25 for a round trip truck fuel cost and a $6 ramp fee just to do a simple diagnosis on this ski. I have to do what I can to work out most of the bugs at the shop.

I'm going to takes the cylinders off and inspect the crank case. I recognized the cose rattle noise from the pump from via LouDoo, but the engine is making a whole separate clunking rattle noise coming from the PTO cylinder as well. The PTO cylinder is the one that isn't firing correctly as well. The crank inspection will be my overall factor if I move forward with my build for now. If the crank is bad... it will be a winter project or a parts ski.

The mpem is a rats nest. It has different components wired in it than the OEM configuration. I tried following the OEM wiring diagram's and it just made it worse. From the pictures, the rectifier's red wire isn't even hooked up to anything.

If the crank inspection turns out to be ok... I'll start overhauling everything to make it perfect again. I already have a new top end on hand that I can use as well.

 

[nsschwenk]

This is what I don't want to see when I inspect my crank. This is a picture of a crank that has bad seals and it is coated with 2 stroke oil on the MAG side.