2002 Seadoo X-20 Running Issue

[OziX20]

Hey guys, i am a new guy from Aus so am hoping maybe someone can steer me in the right direction.

I have previously owned a 2006 Seadoo Sportster and also a 2002 Seadoo Speedster. Both boats were really clean when i purchased them and other than a few minor mods like hydroturf they were pretty much flawless.

I have atm a 2002 Seadoo x-20. I have done a complete exterior rebuild on the boat with paintwork, new trimming and will organise some hydroturf through Cory from hydroturf. Its all new and looks great but have an issue with the boat starting and idling by itself.

It was all running okay when i first had it imported and after pulling the outside apart and it sitting for a few months i cannot get the boat to start and run by itself. The only way i can even get it to start is by priming the boat with the key and holding the motor on crank. Once it holds a couple of revs it will just die down and cut out. If i am fast enough to put the boat in forward and then rev it, it all seems to be working fine but once i go back to idle it just dies down an cuts out.

I havent been able to work out the problem by downloading the manual or having a couple of car/motor mechanics looking at it so if anybody has any suggestions that may be able to help it would be greatly appreciated.

I have only a little bit of knowledge of these boats in regards to motors and stuff like that but i do know that this had had some repairs in the states before as i can see that its been pulled apart before.

Nevertheless the boat was running fine and maybe just something simple that is causing it to act like this but i just want to get her running properly so i can take my first 20ft jet boat out for some fun.

Thanks

 

[Dr Honda]

What engine do you have? It should be the Merc 240 EFI... but I guess it could be the 250 Di engine also.

So... before we can help... we need to know what's under the deck lid.

 

[OziX20]

Sorry i probably should have mentioned that. It is the Merc 240 EFI. After looking a little bit more into it i am thinking that it is a fuel issue as it was all working fine until it sat for a few months. Is it possible that it can be the small vacuum pump on the LHS of the block just after the primer pump. If its not that it may be the oil and fuel pump but dont believe any of these parts are serviceable in regards to do a running repair on them.

Thanks, Kane.

 

[Dr Honda]

OK.... I'll move this to the Merc section.


If it will rev up... but won't idle... then it's normally on of three things....

1) The fuel filter(s) are plugged up. There is one under the lift pump. Its a small metal housed filter. and there is the big "Spin-on" filter on the starboard side.

BUT... when they plug up... you also normally loose top RPM's too. (but can't hurt to change them)

2) The port side temp send has gone bad. once you get it to idle... is it smokey, and rough?

3) The TPS has gone bad. Let's not hope that's the problem. it's a $500 part. I started to look for a cheap replacement last year, but once winter hit, I stopped working on it.



With that said... if you still have the steering assist system still hooked up... try turning your steering wheel all the way to one side. That will give you a bump in the RPM... and should get you started. OR... disconnect the Mercury Throttle Guardian. If you do that... you will be able to give it a little throttle while starting. BUT... check the above 3 first.

 

[OziX20]

Hey Dr Honda,

Thanks for your reply. I have checked the big spin off filter and all appears to be working ok there. I havent been able to find the small metal housed filter so will go and have another good look and hopefully check over it.

The boat i cant even get to idle, once i get it to run i have to slam it in forward and then if i rev it, it seems to sound like all is working okay as the motor isnt lagging or sounding rough but of course no load on it. So not sure whether it is smokey and rough because i cant check it.

The steering assist system has been disconnected and have owned a few seadoo boats so wasnt really sure as to whether i needed that hooked back up as i do know how they perform and are aware you dont rev the guts out of it after a spin as it will just bog down.

I have a mechanic who has been really good on some bayliner trophys i had and he is going to get out on nect friday and hopefully fix it.

I will check for the other filter in the meantime and if that doesnt solve it ill just have to wait for him to come have a look.

I dont know whether this may have any reason why but when i bought the boat the first fuel pump was bypassed and had a old fashioned hand pump there instead. Maybe the first pump wasnt working well but have reconnected it now and all seems ok.

If i dont resolve it over the weekend i will let everyone know what the problem was so hopefully can save someone a headache or two later.

Thanks again.

 

[El Toro 33809]

The good doctor could verify if this is correct, but I was under the impression that these need a battery that is "fresh". If it in good condition and fully charged? I like the steering assist, tug on the wheel when cranking it over will give it a little boost. Plus, it really helps me maneuver at "idle". Good luck.

 

[OziX20]

I did put a brand new battery in the boat so it has had plenty of cranking power. Because i havent taken the boat out yet im not too sure whether i will prefer the steering assist on it or not.

What does the steering assist actually do though?

Was told it just helps you in regards to not over revving the motor when it bogs down.

Thanks i need luck. Lol

I will try and post some pics of how it looked when we got it as i couldnt get the original X-20 decals when i bought it and have tried to do something slightly different. Some might like, some might hate.

Cheers.

 

[El Toro 33809]

I think I like the new interior. Not sure about the graffiti font on the lettering.

The steering assist raises the RPM's when at idle and taking the steering to the stops. It really helps me in the low speed navigation. It will turn very tight circles that way. In addition, if you want to throttle it up a little when starting, tug the wheel to the stop and it can assist with the starting.

 

[OziX20]

Ok so maybe i will check it out once its running at least i know that if i need to have some more control down low i can hook it back up.

Well the new interior is very similar to original just slightly different shades.

With the graffiti font it has actually been tagged by a friend of mine and then cleared over the top.

Either way i really like it but understand not everyone will.

Thanks for your input & help

 

[Dr Honda]

Yes... as above... the 240 EFI don't like a weak battery. When I had my boat out last season... the battery was getting weak, and it would start, and then sputter out. I would have to start it a couple times... and then it was fine. (the voltage needed to come up)

Personally... I don't like the steering assist. I have mine disconnected. (I don't like anything automatic) BUT... in this case... it may help get things going. If the cable is still there... connect it.

I would disconnect the throttle guardian. When they start to fail... all kinds of strange things happen.


Your boat has 3 fuel pumps. 1) The lift pump. It's the electric box on the port side. It only runs while cranking. 2) The pulse fuel pump. It's a square just beside the lift pump, and runs from the pulses from the #4 and #6 cyl. It's the pump that supplies the EFI it's fuel. And finally 3) The high pressure pump. It's mounted in the vapor separator. (the aluminum tank on the front of the engine)


Now... thinking about that... you may want to check the pressure on the EFI. There is a schrader valve on the regulator. (34~36 psi)

 

[OziX20]

Ok awesome. Well i am aware how the fuel system works from looking at other posts aswell but that just explained it alot simpler for me.
Originally the lift pump was bypassed and a hand pump was put in instead. I thought thats not right but left it how it was and all was working ok. Since it hasnt been starting and nothing has changed i reconnected the lift pump and there was no change in it.

The steering assist cable is still there so perhaps i will have a look at reconnecting that and see if there is a change.

How do you disconnect the throttle guardian and where is it located?

I am purchasing a fuel guage to have a look so thanks for telling me what the pressure should be.

For some reason i just have a feeling that the problem is the pulse fuel pump which the mechanic will be bringing out on friday.

With the pulse pump i cant actually see any wiring connected to it so it runs just as a mechanical pump between 4 & 6?

Thanks again.

 

[Dr Honda]

The pulse pump is purely mechanical. It's mounted to the side of the block. Behind it is a gasket, and a hole. It picks up a pules from #4 there. Then, there is a hose that goes from the front cover to #6. Those 2 pulses drive it back and forth. Needless to say, there is an in and out fuel line.

It's only held onto the engine with 2 bolts, and can be disassembled for cleaning, and/or repair. With that said... if there isn't a filter before that pump (because the lift up is bypassed) It could be full of junk.


The guardian isn't in any of the wiring diagrams. BUT... it should be mounted in the helm of your boat. It will be a small black box, with a few wires. It should be connected to the kill lanyard. It basically grounds the coils... so if you disconnect the wire going to the lanyard... it should be fine.


Last thing... since this boat is new to you... have you checked the compression? Are we sure that the engine is healthy? If you have a dead Cyl... it could seem like a fuel issue.

 

[OziX20]

Well i have pulled the pump apart and the diaphragm and springs were all clean and okay. The motor had a compression test done on it not long ago here is Aus and all was okay. I will have a look for the guardian box today and give that a try with it disconnected.

If no luck only 2 more days until a mechanic is coming out to look at it and hopefully we will have the problem sorted out then.

Thanks very much for your input and i will let you know if the guardian box dicsonnected altered anything.

 

[Dr Honda]

Did you test the TPS and port side temp sender yet?

 

[OziX20]

No not yet i am a bit too afraid to start playing around with that stuff especially as you told me one of the sensors is worth $500.

I will check for the guardian box and see if that changes anything and if not i will just wait for the mechanic. Either way hopefully i will know what the cause is by friday and will let you know.

 

[OziX20]

Ok so had the mechanic come out today and found out what the problem is finally. Cylinder 6 is way down on compression and looks like i may have to do a rebuild or buy another motor. It appears that it has been slapped together before we bought it as the crank case has had a repair on it. More than likely it was a quick repair with most of the old stuff in it just to get it running and then get rid of it.

Obviously i bought it so its my problem now.

Whats the best way to do it?

Rebuild and get another case.

Does anyone have a good second hand motor they are selling?

Thanks, Kane

 

[Dr Honda]

Well.... and new case isn't easy to get, or cheap. I think a new engine case is around $2700.

Personally, I would pull the engine apart, before deciding. If the crank is good... I'd bore the one cyl, and put in a new piston. If it's your labor... you may be on the water again for less than $300. (oh... and change the oil pump gear while you are in there)

A welded block is going to be normal for the Merc engines. When they let go... it's a 50/50 chance that a rod could come through the block.

Regardless... it isn't as bad as mine was. We can walk you through a rebuild. :thumbsup:

 

[OziX20]

Holy S^%t. I cant believe the case and piston on yours. I am assuming yours was moving at high revs when your heard pop?

Well now that you have told me that and shown me some pics it sounds like the best thing to do is exactly what you said. I will pull the motor out and then see whether i can strip it down and get back to you. I purchased a shop manual before i found out about this forum but it only has limited info available. Is there another manual i can purchase that might make pulling the motor apart and down easier?

 

[Dr Honda]

If you pay for a premium membership here... you can download the Mercury manual. You can just do it for one month. OR... you can get a used Merc manual for about $50 on ebay. (if you want a hard copy) You want the 2001-1/2 and earlier book. The later book is a little different from your engine.

As far as the RPM's when mine let go... don't know. I bought the boat with a blown engine. Personally... I think that's the way to get a Merc seadoo. Then you know you have a fresh engine, and you get them cheap. (lol) After my rebuild, and fixing all the little issues... I only have $7500 into the entire boat.


Here's a couple of the patch: (why spend $2700, when a few hours work fixes what you have?)

 

[OziX20]

Lol thats awesome. I would probably prefer a hardcopy but ill see how difficult it is first.

Well to have that much invested in a boat with a fresh motor is awesome. LOL

Wish i had of bought one with a blown motor and fixed it instead of getting one that popped a motor before i took it out lol.

And i imagine you have put a few hours on the motor without any issues motorwise yet?

 

[Dr Honda]

Yep... it always sucks when you think you are getting a good engine, and it turns out bad. We see it here a few times a year. Either someone buys a boat/ski that has been parked for a long time... or they get one that runs great... but it gives up after a ride or two. Unfortunately... when dealing with old 2-strokes... that's the gamble.

I generally buy all of my toys as a project. That way I can buy cheap (pay cash) and fix them properly.


Yes... I have some time on the rebuild. I didn't get it done until almost the end of summer last year... but I took it out every weekend, and we took it on a 4 day vacation to Deep Creek MD. I probably have 100 gal of fuel though it by now. I know that sounds like a lot... but I think it's drinking 18 gal/hr at the upper throttle settings. So... that's probably only 5 to 10 hrs run time.

Since I do my own work... I know that it was done right. (or at least acceptable, LOL)

 

[OziX20]

Lol well acceptable is more than okay if its still running and you get to use it.

At least it goes faster than mine anyway.

I am not too shattered about it, s&*t happens so it just means i will get to learn a bit more about these motors in depth.

I will get it out hopefully soon and let you know what i find. No doubt ill be asking more questions from you lol :facepalm:

Thanks again Dr Acceptable :thumbsup: