Any advice on seadoo 951 rx di 2000

[Fosta]

Hi guys,
ok some of yous know ive had a number of problems with my seadoo rx di!
in a nut shell when I bought it just over 2 weeks ago I took it out for a test ride and it was misfiring and it wouldn't rev over 4500rpm then after 10 mins we had full revs and it was a flying machine! but with this it had a " MAINT" and "12V LOW! light.

so I took it home feeling sort of happy and thought it would just be something simple! that aside ive took it out a few times now and its had problems starting! if and when it dose it misfires really badly and now and again it will feel awesome for a minute or so then it will start missfiering and give out 3 loud beeps then go into limp mode!
the misfiring seems to have gotton worse and its getting harder to start!

here is what ive done so far:

. changed spark plugs and gapped correctly to 1.1mm
. changed rectifier as it was damaged.
. I found that the earth cable going from the negative battery terminal to under the starter motor was badly corroded and snapped at the battery terminal end but was only held on by instulation heat shrink so took me a while to notice that, but someone had already put and extra earth cable in and fixed it to the engine mount near the battery! I got out my multi-metre and probed the positive battery termamal and then probed the engine manifold bolt to see if that cable that had been put in after was earthing the engine block and I got a reading of 12.3v so it is earthing!
ive went ahead and took out the old corroded earth cable and put in a new one to the negative terminal to under the starter motor just incase. so the engine has 2 earths :/

.ive cleaned the RAVE valves but noticed that one of the valves O-rings looked slightly too big and although it went in the hole it didn't sit /hug tight around the RAVE valve shaft. ( this is the only thing I havnt fixed yet.)

.replaced the battery for a good one.
. replaced starter motor (as I damaged the last one keep cranking the engine trying to start the ski.)
.checked all fuses
.drained and refilled fuel tank with shell v-power nitro 100 octaine.

But the ski still struggles to start and misfires badly if it dose start. is there anything else I could look for? it gets fuel and its giving a spark. im stumped with this engine I just cant work it out!

after changing the rectifier there is no maint light or 12v low showing and its not beeping to tell me of any problems, just the normal beeping when I plug the key in.
and there is no fault codes stored.

here is some pictures of some of the faults ive came across:


rave valve O-Ring looks too big. (not replaced yet.)




EARTH CABLE.



starter motor from constant cranking to try and work out the problems.




I hope someone can point me in the right direction to what the problem is. ive spent every night for the last two weeks searching to try and find what my problem might be but no luck yet. after doing all this research ive noticed that a lot of seadoo 951 DI owners seem to have nothing but problems with theese ski's

thanks guys. FOSTA

 

[Fosta]

Took the brand new plugs out to inspect, they look sort of blank.

Any ideas what's going on guys?

 

[AdamXP800]

I see mocha on those plugs. Maybe a tad dark but they look good.
That can't be the right oring for the RAVE

 

[Fosta]

I see mocha on those plugs. Maybe a tad dark but they look good.
That can't be the right oring for the RAVE

Yeah I thought that with my rave valve, I will be changing that one out but that wouldn't give me all the problems I'm getting would it!?

 

[Sportster-2001-951C-Stock]

You don't want to see white or grey or black, the cardboard brown(mocha) color is the normal oil film and that's what you want to see in any two-stroke that uses API-TC oil for lube.

What I think I know, until proven wrong by someone smarter than me:

If you see black, it's likely fuel soot from too much fuel, could be wrong type of oil or too much oil, IMO most often black is too much fuel. Gray is aluminum from your piston and very bad news! White is probably impossible but it's bad news too, plug is wrong heat range or the cylinder is not firing and washing the plug clean with fuel while causing cylinder damage due to dead cylinder.

 

[Fosta]

So is that a normal looking plug then?
If so what could be causing these hard starting issues and bad misfiring?
Huge thanks guys

 

[68ragtop]

Great comment on the oil sportster. I have seen different oils make plugs different colors too. If I post a picture of the plugs I run in My snowmobiles, you guys might be surprised. Lol, they are almost grey, but piston wash is perfect at the same time.

Fosta, did you happen to remove the throttle bodies & inspect the reeds? Could be you have a damaged reed, or reed cage?

 

[Sportster-2001-951C-Stock]

Great comment on the oil sportster. I have seen different oils make plugs different colors too. If I post a picture of the plugs I run in My snowmobiles, you guys might be surprised. Lol, they are almost grey, but piston wash is perfect at the same time.

Fosta, did you happen to remove the throttle bodies & inspect the reeds? Could be you have a damaged reed, or reed cage?

Yes, the oil's additive package is what causes our mocha brown color, and grey insulators in a 2-stroke always make me nervous b/c I've seen this many times and the result was not constructive.

For the OP, I think you should look carefully at your ignition coils and the plug wires, sometimes the wires center conductor can burn at the end where it connects to the plug adapter and triming off the end 10mm and refitting can take care of that.

I assume you installed the correct spark plugs, if not then get the correct ones.

It has spark on both plugs but misses and is hard to start -

Just b/c a plug will fire out of the cylinder in air doesn't mean it will while in the cylinder, b/c it takes more voltage while in the cylinder under pressure to make the spark jump the gap. As the voltage rises to some point the spark will normally jump the gap but this voltage cannot happen if the coil is breaking down and leaking electrons due to some kind of insulator damage.

I'm surprised if your ski is going into limp mode it doesn't report a fault, but I don't own a DI. There is a troubleshooting chart in the factory service manual that may lead you in a logical direction, based on the symptoms you are experiencing (buzzers beep sequence and such).

Good luck and keep going, measure the cylinder compression if you can (absolute marine engine rule).

Keep us informed of your progress!

 

[Sportster-2001-951C-Stock]

So is that a normal looking plug then?
If so what could be causing these hard starting issues and bad misfiring?
Huge thanks guys

It is very close to normal but as Adam mentioned it's a little on the dark side. I'm guessing the plug was not quite reaching normal operating temperature and some fuel soot is causing the slightly darker color.

This would be consistent with your symptom of an ignition miss, for which I gave some ideas in the above post.

Also the 951 is known for damaged reed valves occasionally but it seems to me if that were the case it would run like crap all the time. Maybe one of them is partly broken, I can't say it's not.

As far as reeds go, I have always noticed in a carbed motor a weak or broken reed tends to spit fuel out of the carb throat during idling, perhaps you can feel a slight puff of air coming from the throttle body in the case of an injected 2-stroke.

Remove the spark plugs and give it a crank while comparing the sound at the throttle body, it should not puff air at your eyebrows, it should only suck air inward into the crankcase. Maybe you can even turn the motor by hand and feel at the intakes the rush of air inward as the piston rises to top dead center but not air coming from the throttle body as the piston drops into the crankcase?

This is the quick and rough method I use for judging the condition of reed valves by these observations. The reed valve is a simple one-way check valve to allow air into the crankcase and not back out of the crankcase, it should breath in, not out.

You will probably want to prop open the throttle butterflies while rolling the motor over during this test.