2003 rxdi died on water won’t start

[Nski03]

Hey guys I’m hoping y’all can help me out with this issue I got myself into.
picked up an 03 rxdi for what seemed like a decent deal. Story from the seller was that It started taking on water only when running and ran rough in the mid range. It ran great on the trailer when I picked it up. Didn’t have access to a comp gauge at the time of purchase so I took his word that it came back at 130 on both cylinders.
I was correct in assuming the water leak was from the mid pipe and patched that up. Assuming that might have been what was causing the ski to run rough too, I took it out to see if I got lucky and was good to go. I didn’t get any water in the hull but it ran rough in the mid and great on the top until it started sputtering and didn’t want to get over 3k.
got it home pulled the plugs and they were black wet and fouled. Cleaned them up. Drained the gas and replaced the fuel. Cleaned up the rave valves. Now it runs even better than before on the trailer. Put it in the water and instantly get a low 12v warning. Let it idle a bit and it goes away and seems to be running the best yet. Make my way the the NWZ and as soon as I get to open water and open it up it stumbled in the mid again but the top screamed..... for about 45 sec and then cut dead .Had to get pulled back in. It only cranks and no fire. I have spark. I can hear the fuel pump when key is attached. I have a cheap press in compression gauge that I don’t trust and it’s showing 90psi in the front and 130 in the rear. Both rave valves are also cracked at the stem “possibly by me over torquing”. Front plug is dry and black rear is slightly wet and black.
should I move forward with what might be a fuel issue to hopefullyget to ride a little this season or do I definitely need to do at least rings before moving on? I’m not afraid of turning wrenches but I’m not super familiar with2-strokes and don’t want to cause any unneeded damage and costs.
thanks so much in advance.

 

[Mraw]

I would double check compression with a quality gauge, there should be no more than a 10psi difference between cylinders. If those numbers are right then a top end rebuild is in order, you will also have to figure out what killed the low cylinder in the first place

 

[Nski03]

I would double check compression with a quality gauge, there should be no more than a 10psi difference between cylinders. If those numbers are right then a top end rebuild is in order, you will also have to figure out what killed the low cylinder in the first place

Yea I definitely want to get more accurate numbers for the compression.
so as I understand it, even if I fix what cause the issue in the first place and I try to ridewithout doing the top end , I will most likely destroy the bottom end?
what is it about uneven compression that willdestroy the motor?
Can I do the top end with the motor in the ski still. All the vids I’ve seen the guys have it out on a bench.

 

[Mraw]

I'm pretty sure you can do it with the engine in the ski, running with low compression won't necessarily damage the bottom end but can cause running issues like your having now

 

[Nski03]

Ok so I got my hands on a better compression tester and the numbers stayed about the same. It was more like 85 in the front and 120 in the rear. Replace t rave valves came in early today so I popped those in with new plugs. Cranked it over once or hahas before doing the fuel and it actually fired right up but sounds like a pretty nasty rod knock.
I assume my best bet if I don’t want to lose too much money would be to find a decent low hour engine? Any good local places in the New England area?

 

[jhjesse]

If it were me I would pull the engine and rebuild it myself as long as the crankcase is good. When these engines knock loudly there is a better than good chance a rod has started to go through the case.
There are plenty of members here that can talk you through most anything that comes up.

Whether you rebuild or swap engines there are several things you are going to need to do as you have several things going on here.
1. You need to replace the rectifier to eliminate the 12 volt low alarm. Go OEM
2. You are going to have to get the injectors cleaned to eliminate loosing another cylinder.
3. You need pull the oil tank clean it, replace the oil filter and lines. Pre bleed the lines. I recommend Amsoil interceptor or OEM XPS full synthetic and never mix oils.
4. Pull the fuel pump clean it and replace the internal fuel filters. Replace the external fuel filter while you are at it.

Good luck.

P.S. If the engine has more that 100 engine hours I would not cheap out with just a top end rebuild.

 

[Nski03]

And the last thing I should add is that I paid 2k for it believing it wasn’t anything major. I was confident in doing a top end with some pep talking but a whole rebuild might require someone looking over my shoulder now and again.
I guess I can forget about riding this season at all but I’d like to be able to ride this thing for a season or two and not be top upside down when I resell it.

 

[jhjesse]

Ouch! Two grand.
I have done top ends on DI skis with well over a hundred hours before with success, but I was also “riverboat gambling.” I got lucky.
No matter what you do, I highly recommend pulling the engine because you need to be able to inspect the bottom of the engine for cracks.