2002 RXDI won't get up to speed.

[kneedragnr1]

Hi all.
My son was riding my RXDI when all of a sudden it won't get up to speed.
I started looking for anything obvious.. spark, pump/impeller, et cetera but could not find anything obvious. I rolled it in the shop and found that a spring had came off one of the (for lack of better words) bladder for one of the Rave valves. I went ahead and took both off, cleaned everything and reinstalled. Out of the water test seemed like the craft was performing fine. I have a decent size pond out back, so I tested there. When I first started it in the water, the red light came on and stated "maint." But quickly went away. I let it warm up a bit and it didn't seem to want to idle right, as if cold and wanted to die. I throttled it a bit, backed it off trailer and ran it around the pond a few times. The trim seemed functional and responsive but it never had much punch (as it did prior to) out of the hole. Midrange seemed okay but never really got up to speed, no matter where trim was, high or low.
I thought it could be in limp mode but it revs up to well over 5K (max) in and out of water. At present, I have pump off craft and checking for issues. Clearance between impeller and wear ring looks good and, other than a few small minor blemishes on the trailing edge (exit side), impeller looks good. I've also checked Rave valves again, which seem fine.
Any suggestions would be greatly appreciated.. Thanx!

 

[jhjesse]

Perform a compression test. Should be 135 to 140psi. Anything less than 120 and will need a rebuild.

Maintain light could be a rectifier. Start on trailer and rev to 5000rpms with volt meter attached to the battery. Needs to read 13.5 to 14.5vdc. Anything more or less and Rectifier will need replacing.

 

[kneedragnr1]

JHJesse, Sorry I didn't see your reply sooner. I have did a few things since I first posted this. First, I was led to believe that this was a DI model when, in fact, it is a carbureted RX model. Also, even though I stated before that it would rev up to over 5000 in water, I think it was more like 4600~4700.
So, I've pulled carbs off and went thru them. I noticed that the throttle cable actually splits into two cables, one going to the carbs while the other goes to the oil pump regulator and the cable was broke there.
I purchased a new one, installed and made adjustments according to the shop manual. I tested out of water and it seemed fine, running up to 7200 rpm. Checked voltage after warm up and running and it stays right at 14 vdc. I then took it out on the water and tested. It would only reach 4600 rpms or so and seemed to take a bit to get there. I then did a compression test and can only get a little over 100 psi. However, I am questioning the gauge and the integrity of it and hose/fittings. So, jury is still out on that one until I get a known good gauge set up.
Also, after changing to new/gaped plugs and running a few times, I noticed that the front plug seems to look new, while the back plug looks little brownish and just a tiny bit oily. I question if there is some issues with the front cylinder getting the fuel it needs. One thing I noticed after going thru the carbs is that the front carb has a "pulse" stamped on the side plate and a fuel tube on the side seemed to not allow me to blow thru it when apart. It's a good 1/8th inch I.D. or so, so I should be able to blow thru fairly easy I would think. Not for sure it there is an orifice or some other restriction that is factory installed or that there is foreign material built up there. I tried pushing a small piece of bailing wire thru it, to no avail. Again, jury is out on that, as well.
Something that is bouncing in the back of my head (hoping not the case) is that when this thing broke the oil pump regulator cable, it was ran several times trying to troubleshoot it. I'm wondering if it didn't cause ring and cylinder damage? One would think that there would be some sort of fail safe feature in play just incase something so important as OIL was involved, huh? Yet, I don't think there is.

 

[jhjesse]

When oil pump cable breaks the oil pump goes wide open as protection. If in fact it is 100psi compression it is time for a rebuild.
There is a resurge jet in that small hose part #72 on diagram below:
http://partsfinder.onlinemicrofiche...&make=seadoopwc&a=166&b=18&c=0&d=-CARBURETORS
When going through the carbs make sure to use only genuine mikuni parts as all others are junk.
Also good idea to replace the needles and seats in the carbs using the original springs while setting the correct pop off pressure otherwise you will have a condition as you described.

 

[kneedragnr1]

Yeah, I've ordered a new compression tester kit that will be here Monday 7/24/17 and will test then.
If I understand this correctly, the oil pump regulator is wide open when the cable breaks? Because, with the new cable and the throttle wide open, it rotates in the opposite direction (CW facing front of motor), which would seem to be closing, giving less oil, if that is the case.

The plate that I am referring to is not part of the fuel pump assembly. It is on the side of the front carb and has a 90 degree swept copper tube going in it. The plate has been bored parallel the face and has a ball that has been compressed in the side as a plug from factory. I question whether they installed an orifice or not before they plugged it.

I still question why the new plugs look so much different from one another. The rear one having a dark, oily tent while the front remains new looking. Something seems to be up there, just haven't put my finger on it yet.
I certainly appreciate all your help here. You've surely went out of your way. Thanks!

 

[kneedragnr1]

I noticed when I set up the new cable that I had to set the oil pump regulator cable adjustment so that two lines matched up on it, which pulled it away from it's maximum CCW rotation. I suppose that it could go to a different port, allowing maximum flow upon cable breakage.

 

[jhjesse]

The brown plug is getting good fuel oil mix. The new looking plug (mag cylinder I assume) is not getting enough fuel therefore it is running lean.
If you keep running it that cylinder will seize and ruin your motor.
Again I recommend you pull the carbs off give them a good proper cleaning and rebuild with only genuine mikuni parts. Replace the needles and seats while in there using the old spring. Set the correct pop off pressure when reassembling. There is a couple of YouTube videos on setting pop off pressure.

As far as the plate with the ball, I'm not sure from your description exactly what you are referring to, pictures can help. I will say that the ski has run since 2002, so l don't understand the questioning of orfice installation setting?

You are correct by setting the oil pump by lining up the lines. When the lines are aligned, that is the lowest the oil pump is pumping. When you open the throttle the volume increases. When the cable breaks the lever goes back past the low volume point and opens back up to wide open.

 

[kneedragnr1]

Yeah, I kind've figured as much with the way the plug looked so new.
I'm not really questioning orifice setting as much as I'm questioning if there is even one there. I'm thinking that there isn't and it could be foreign matter restricting flow.
I should get the new compression tester today or tomorrow and will be able to get a more accurate reading on compression. Hopefully it's above 120.

 

[kneedragnr1]

Well, it seems that the old gauge set was okay. Compression is below 120.
Guess it's time to freshen up the top end.
I'm hoping that a hone and re-ring does it.