95 XP 720 erratic throttle, sputtering, dieing after carb rebuild

[Kal Brigger]

I rebuilt the carbs with Mikuni kit including Mikuni needle and seat (1.2)
I set both low speed at 1 3/4 turns and the other at 0 (when I was tearing them down I noticed that one was at 1 1/4 turns and the other was over 3 but it ran OK at best).
Pop off test had one of the carbs at 42 psi and the other around 46.
I did not soak the carbs in anything but I did super deep clean them paying attention to EVERY nook and cranny and orifice then after they were dry, I proceeded to install the rebuild kit.
I have new gas, new fuel lines, new in line filter with the glass so I can see the fuel flowing, new on/off/reserve switch (which I'm not 100% sure it's working properly since I was noticing some fuel drip through the filter while in the "off" position but it was brand new, still in the bag before I installed it), new fuel/water separator O-ring, all linkages are working and lubed, oil pump lines match up, choke butterfly valves are synced and I'm showing around 132 and 133 on compression. I double checked all the oil lines when the carbs were still off- I recently changed them and changed oil to XPS.

Anyway, after sitting for a couple of weeks, it started great on the trailer but with a little black oil out of the exhaust (for the first time since bringing it back to life). The plugs showed the perfect cardboard color and the oil system must have been working since it smoked what I would consider the correct amount. There was a trippy smoke that poured out of the exhaust like fog in a horror movie after I shut it down. The only other thing I did notice was the RPMs started to slowly rise but of course I shut it down after about 10 seconds so I couldn't diagnose that very easily.

After getting it into the water, it didn't want to start. I was hoping that by rebuilding the carbs with Mikuni rebuild kit and setting as close to perfect specs as possible, it would fire up without having to do the contortionist act with the start button, choke and elbowing the throttle.
It took several minutes to fire (and this is about 5 minutes after it was running on the trailer before getting in the water). When it finally did start I had to keep feathering throttle to keep it going. I did 4 straight lines about 1/2 mile each, all trying to keep it going. It was very erratic and random up and downs in all positions of throttle. When it did die, I had to wait a minute or two to get it going again. There were brief moments of high RPM and high speed then start to die, bog down, sputter and occasionally just died.

I pulled the plugs and noticed they were a little wet and a little more black than before. I changed them with brand new ones (NGK) and it didn't start again, even on the trailer.

There was plenty of gas in the filter, no beeps from the new buzzer, no backfiring, and a normal amount of smoke when it was running on the water.

If this was happening on a car (which I'm more used to working on), I would guess it was a plug not firing or a bad vacuum leak.
I did use new gaskets under the carbs but nothing on top of carbs where the air box attaches.

I don't know anything about the Rave valves or what symptoms surface when they go bad and I don't know what/how to check electrical issues on these motors when it comes to running.

Everything else seems to be working (except for tach- if you have any suggestions on how to test that also, I'm all ears).

Thanks ahead of time!!

 

[mikidymac]

When I have seen the black oil coming out of the exhaust it is usually a leaking needle and seat.

Did you pressure check them after putting them back together? They should hold 10 psi no problem.

 

[Kal Brigger]

I did the pop off test resulting in 42 and 46 psi.
After the actual "pop", they held pressure for at least a few minutes and no bubbles in what was left of the wd-40.

That's the only pressure check I did. '

Did I skip a step?

 

[mikidymac]

When you get them back together and the diaphragm covers on you should pump them up to 10 psi and make sure they hold pressure.

Just to be sure nothing is leaking.

 

[Kal Brigger]

yeah... I didn't do that.

So that might be the answer to the oil out of the exhaust but would it also be the cause of the other problems like not running or starting right?

 

[Coastiejoe]

Did you use OEM gaskets or aftermarket?

 

[Kal Brigger]

I can't remember where I got the gaskets from.
They're green with some words on them (can't remember what they say) and feel like paper about 1/8" thick at most.
I didn't use any kind of sealer on them either- not sure if I was supposed to or not.

 

[Kal Brigger]

Finally getting back to this ski. I was "notified" that I need to get the wife's XP running by this weekend (4th of July).

I pulled the carbs and did another pop off test first.

One pops at 46 psi and the other pops at 42 psi. Do these need to be exactly the same?

I used the genuine Mikuni needle and seat and have very minimal bubbles occasionally after they pop and before I release the pressure. They hold pressure for at least a few minutes but I haven't tested that part for any extended amount of time.

I put them back together with the diaphragms and pumped to 10 psi. They both held for at least 10 minutes without leaking.

I'm going to replace the yellow/see-through fuel lines around the carb to the normal black lines b/c I think the screw type clamps I'm using might be digging into them too much.

I have new name-brand base gaskets to use when I reinstall.

I'm going to check the fuel separator and selector switch to see if there is anything wrong there.

Any other ideas while I have the carbs off?

 

[Kal Brigger]

Went ahead and reinstalled the carbs with new gaskets "Intra-something" brand. Made in USA

Checked the separator filter. Filter had a little bit of junk in it but cleaned it out. The new O-ring I previously installed seemed too big and would not sit down in the groove. I found the original that was installed when I bought the ski and checked it over carefully. It still looked good and it fit correctly.

Started it up and ran it about 45 seconds before stopping it (three times, cooling between for about 15 minutes).

It seems more sluggish then it previously did (yes, I know its a cold start but I'm comparing to previous cold starts).

Good amount of liquid coming out the exhaust. Started off looking like gas with a little oil then ended up looking like liquidy black oil.

I didn't do anything with the selector since it was holding the fuel back when the carbs were off and then it flowed after turning to "on" like its supposed to.

I have a feeling the water test while show the same results as last time (erratic and random throttle, dieing, ect.) but I'm crossing fingers.

Again, any thoughts, tips, whatever would be appreciated!!