96 XP First Ride of The Day Sputter

[skewba98z28]

Ever since I bought my XP it has had what seems to be a blubbering rich sputter when you first go WOT for the day. I usually idle around for 2 to 3 mins to allow the motor to warm up some (could be a issue) and then I'll slowly transition the throttle to WOT. Then when I get past 1/2 throttle to wide open it sputters like its rich and won't get up on plane. I can do that a few times and pull it back to 1/2 throttle and then mash it again WOT and it will "clear" out and run like it should the rest of the day. When its sputtering I can slowly pull the choke out and it dies instantly and doesn't pick up any rpm before it dies so i'm assuming it its not lean. Its not hard to start when I first arrive to the ramp. It takes slight choke like most and it fires right up. Doesn't smoke real bad either.

To try to remedy this and for piece of mind I rebuilt the carbs including needle and seats, installed new plugs, and installed a new fuel selctor as it used to be bypassed. Needles are at stock settings (Low 1 out and High 0 out) and the pop off is around 26-28psi. Before the pop off was the same, but the needles were (Low 1 1/4 and High 1/4 out) I also pulled the plug boots, cut the wires back, and reinstalled them.

I put new plugs in it and gapped them correctly before I rebuilt the carbs and that didn't fix it. It acutally seemed worse. The old plugs were gapped wider than the new ones. Also I could get it to clear out and run smooth for a few seconds at WOT and then it would go right back to sputtering. I could ease the choke out at WOT while it was sputtering and it would die instantly.

Today was the first day on the "new" carbs and it fired right up at the ramp. I idled around a minute or two and at this time I eased out on the choke to check for a lean low end and it died instantly without picking up any rpm. I fired it up again and blipped the throttle a few times and started slowly transitioning up to WOT. It was smooth until right before the raves like normal. After the raves opened it started doing the same sputter it was doing before. Ease the choke back and it dies instantly so its not lean. After a few tries it cleared and ran great. I ran about 2 gallons of fuel through it, the plugs look fine, cylinders feel normal heat wise, and the plugs do also. The rpms follow the throttle with no hesitation anywhere other than right when the raves open up which is normal. It seems all is well once you get past the initial sputter....

Is there anything i'm missing here to try to remedy the first WOT sputter or is that just the nature of the beast. The ski had been sitting about a week so i'm going to try it again tomorrow and see what it does. My spx does the same thing but only for a second or two and it clears out.

One thing that I could think of is my oil pump adjustment is set to the rich side so its possible i'm oil fouling the plugs as i'm warming the machine up??????

 

[Dr Honda]

What you are describing is very typical of a high performance 2-stroke engine. My XP will do the same exact thing. Actually... most of my "Seadoo" watercraft will do that. It's basically because they are squeezing so much power out of that little engine... they have to tune it for normal operating conditions... and it leaves the "Warm-up" time on the rich side. So... until you purge any extra fuel... and you warm up the tuned pipe... it's going to have a miss or sputter.

FYI... every one of my 2-stroke dirtbikes have also done this.

Last thing. If it gives you this same problem after it's been "Cleared out"... but you have been idling in a no wake... then your low needle needs to be turned in a little.

 

[skewba98z28]

I'm used to having to "clear them out" but it just seemed like the XP was doing it worse than it should. I need to consider though I really haven't rode it all that much and I have probably checked the compression once between each ride so that is not helping the loaded up condition. At least its a rich sputter and not a lean bog. Like I said it feels right once its going. Snappy throttle, smooth rave motor transition, no dead spots, and hard acceleration. Thanks Honda!

 

[Matt Braley]

Keep in mind that a rectifier heading south will act like this sometimes. I have had them warm up and act ok for awhile, then fail the rest of the way a month later.

 

[skewba98z28]

I'll keep that in mind Matt. I owned a RFI so I know all about rectifier troubles

I took the ski out again today for testing and here is what it did.

Started it out of the water and blipped the throttle a few times and then shut it off.

Backed it in started it up and idled away from the trailer for about a minute.

Slowly advanced the throttle and it started the rich sputter at around 1/2 and sputtered all the way to WOT.

I let it sputter for a few seconds to see if it cleared and it didn't. I repeated that a few times and it took off.

WOT felt great and sounded great. No surging, accel lazyness, or rpm fall off. I backed it out to around 60% and held it there for around 10 secs and hammered it again and it picked right up.

I chopped the throttle from wide open, turned the boat around at an idle and hammered it again and it did fine. I did this a few times with no issues.

Then I slowed down and let it idle for a minute. I then advanced the throttle to around 30%-40% and held it there for around 15 secs. I then hammered it WOT and it sputtered. I let out of the throttle and hit it again to try and clear it and it sputtered again.

At this point I was headed towards the trailer so I just loaded it.

I pulled the plugs and they were wet with a clearish black liquid color.

So i'm thinking I need to back the oil pump off a bit as it is set rich also i'm going to go in on the low speed needles slightly because it seems to have a overly rich bottom end. Do you guys agree? Any tricks on adjusting the low speed needles with the stock airbox on? Can I pull it and leave the screen on the carbs for testing purposes or will that change the settings like a set of flame arrestors? I had my gopro camera with me to document the issue, but I turned it off instead of recording!!!

Also for clarification. Less pop off psi is richer and a higher pop off psi is leaner correct?

 

[purple_people_eater]

what is your water pressure regulator set to? you might want to check it and clean it before you do anything else.

 

[Matt Braley]

Yes, less pop off psi is richer but this should only effect your "just off idle" response. I like the water valve idea, it could be full of sand.

 

[Dr Honda]

For a recreational ski... I don't like to tune with the pop-off. If you are going to take the carbs off... verify the pop-off, (I like to me on the lower end for an 800 engine) and the pilot jets.

 

[skewba98z28]

Ok guys I made some progress and I think I found the real issue. First thing first:

1. I went in right at 1/8 of a turn on the low speed. Took it to the water, fired it up and it took slight throttle to start it. Could be idle screw, but i'm insure since I don't have a tach. seems to idle correct in the water, but I don't want to go off of "seems" so a tiny tach is on order. Now I idled around for about 30 secs. stabbed it wot and it took of like it should. It then reached top rpm, faded off, and started to sputter. I idled around a minute and tried it again and it did the same thing. Hmm sounds rich.

2. I remember by high speed needles were closed, but not snug. I pulled the PITA airbox off at the dock, snugged the high speed needles thinking it's rich on top end. Launched and it did the same thing.

3. As I was adjusting the high speed needles I noticed some water on the carbs. Not a ton, but it was there. Now i'm thinking exhaust leak! I pulled the seat off fired it up and it ran perfect. I looked down and at high rpm the manifold to pipe gasket was spewing like old faithful. Also my water box is leaking around where the regulator screws in. I made a couple more passes on it with the seat off and it was flawless.

SOOOOOOOO I'm going to go back to the original settings on the carb because I was tuning with a exhaust leak and fumes in the hull. Order the parts, fix the leaks, and try again. Hopefully that will take care of it.

 

[skewba98z28]

O.k. guys I got the exhaust leaks fixed and its doing the same thing. I believe it is just cold natured like Honda said. Once it warms up it runs perfect. You can idle around for a minute or two and stab it WOT and it picks right up. For now on i'll idle around the no wake zone longer and i'm sure the 70 degree water is making it take longer to warm up and clear out. :thumbsup:

 

[skewba98z28]

I'm gonna try a "new" water regulator or just jet it. I pulled mine apart today to find water standing in it and a rusty clamp that was started to punch a hole through the bellow. I don't know if its leaking there, but its obiviously leaking somewhere. I also noticed my ski has somewhat of a quiet exhaust note so it could be dumping way to much water into the pipe. If that doesn't help the issue i'm just going to roll with it

Is there any drawbacks to just jetting the water vs actively regulating it?

 

[skewba98z28]

Ok guys I got it fixed. I installed two parts at once, but i'm pretty sure it was my water regulator.

First thing the water regulator was leaking.
Second thing was the regulator was about 1 3/4 out from bottomed out instead of 3. So leaky bellow combined with a stiff spring would for sure cause it not to close.

I also installed a new voltage regulator, but I think my old one was fine.
She's turning 6850 all day long!
Thanks for the help guys!