1996 XP Bogs down when cold

[amarzzarella]

Newbie here with a perplexing problem. I have a 96 XP That I'va had for three weeks and it bogs down when it's cold. It idles fine but when you give it gas it goes nowhere. Once it warms up (after ten minutes or so) it runs fine and runs all day. Here's what we have done so far:

1. Pulled the plugs, there is a lot of oil buildup on otherwise great looking plugs.
2. Performed throttle and oil alignments but no adjustements were needed on either one.
3. The carb is an aftermarket one that I can't seem to find any info on. I am kindof reluctant to take it off for now because the last time it was done they (not sure who) used RTV instead of gaskets. I'd like to do a rebuild on it but won't be able to order parts til I get it out and identified.

Have not performed a compression test yet but plan to do it this week.

Also the VTS does not work. I have read a lot about the motor getting wet and shorting, but is there a good way to troubleshoot this to verify. I have looked through the forum but didn't see anything.

Any and all help would be greatly appreciated.

Andy

 

[Dr Honda]

Welcome.


First... check your compression.

Second... pull that carb. RTV is not an acceptable base gasket, and may be your problem. RTV is not directly fuel proof. couple that with high vacuum, and you may have a leak somewhere.

While the carb is off... open it up, and clean it.

Post a pic of the carb(s), we may be able to ID it for you.


As far as the VTS... yup... the boot at the rear of the hull rips, and the motor fills with water, then it shorts out. If it doesn't short out first... it shorts out the MPEM. (you got lucky)

Pull it out, disassemble, and clean the gears and the motor as well as you can. Sometimes, you can get them to come back to life... or you can change the motor in the housing.

 

[amarzzarella]

Tony,

Thanks for the input. I will try the compression test and get back to you. I'm not real thrilled with the RTV, but I also didn't want to get to a point of no return on the carb without knowing if I can get a rebuild kit for it.

Andy

 

[amarzzarella]

OK checked the compression last night both between 145 and 150. I've attached some pictures of the carbs. They may be stock I don't know but all I have to compare them to is a friend has an xp and his are different and I can't really tell by the pictures in the manual. I really don't want to pull the carb until I can ensure I can rebuild it fairly easily and quickly. As far as the VTS goes I disconnected the leads so I don't have to worry about any feedback to the MPEM and I will deal with that when I break it down this winter. I did realize I have the gray fuel lines so I will be changing them tonight. Any help would be greatly appreciated.

Andy

 

[sketchpad]

after you change your fuel lines you're going to have to clean the carbs, check both filters. the green stuff from those lines builds up in the nozzles, clean your filters.

and replace all lines not just grey ones...on mine there were a couple of black, such as the pulse line, but thought it best to change them all when doing it

 

[amarzzarella]

Thanks sketchpad appreciate the input

 

[sketchpad]

dont thank me, thank all the guys on here, I'm new and am learning from them

 

[amarzzarella]

Sketchpad, Since you have a 96 XP can you tell by the pictures if the carbs are stock?

 

[sketchpad]

my uneducated opinion, the carbs look stock, but your flame arrestor looks aftermarket. I have one that sits on both carbs instead of what looks to be one on each carb for you

 

[amarzzarella]

Thanks again

 

[amarzzarella]

OK here's the update so far:
1. Changed all fuel lines except the vent (That one is really hard to get to). The hoses were really gummed up, and I cleaned all the fitting and the fuel selector (that was really bad).
2. The carb is a BN40 so I got a couple rebuild kits and am about 75% of the way through that and will finish it tonight. A little disappointed with the rebuild kit. It didn't come with gaskets for where the carb mounts to the engine or the air filters, so had to amke a quick run to the auto parts store to buy them.
3. The VTS motor was dead, I broke that down and cleaned it up the best I could, put it back together and IT'S ALIVE. Can't wait to get it back together but I got to check the boot still (it was dark when I got to the VTS). I think the boot was repaired because the motor compartment was dry, it has a lot of salt in it that I still have to clean out, but I am pretty excited.

Hopefully when I finish the carb rebuild and get it running all my problems will be gone. I can't wait.

Thanks for all that helped and I will give an update after I take it out this weekend.

Andy

 

[sketchpad]

thats awsome
sounds like you're a step ahead of me, doing a top end rebuild right now.

I have the same non working vts, but you've given me hope, so while i'm waiting for the machine shop to take their fingers out of their ass that'll give me something to do. what did u use to clean it out? just carb cleaner?

 

[amarzzarella]

Actually I work in an electric shop so I had access to contact cleaner. I wouldn't recommend carb cleaner, it may break down the insulation on the wire in the motor.

Good luck

 

[sketchpad]

cool, thanks i'll try that

 

[amarzzarella]

No Joy in XP Ville. We have spent the past couple of weeks doing everything we can think of and no improvement. The actual problem is a misfire which caused the sea doo to bog down. Here's a total rundown of what we have done so far:
1. Changed all fuel lines except the vent (That one is really hard to get to). The hoses were really gummed up, and I cleaned all the fitting and the fuel selector (that was really bad).
2. The carb is a BN40 so I got a couple rebuild kits and completed that.
3. Performed oil pump and throttle cable alignment check, everything was right no adjustments.
4. Replaced the Ignition coil, wires and plugs.

The sea doo starts fine everytime and will idle as long as you let it. The first time you get on the throttle it seems to rev up fine, but as soon as you let off throttle the misfire starts. I haven't had it in the water since we did the above work so I am only assuming it will still clear up when it warms up. Any and all help/input would be greatly appreciated.

Andy

 

[amarzzarella]

One more thing... I read on another web site to try to disconnect the rectifier and see what that does. I did it and it runs like a champ. I tested the output of the rectifier and it is 55 volts at high RPM and 25 volts at idle. I understand that it should put out between 14 and 15. So I am assuming it is bad. But unfortunity the person on that site replaced the rectifier and the problem did not go away. So I'm a little reluctant to replace it and have the same problem. Does anyone know what voltage the magneto should put out?

 

[sunbaby69]

run power directly to VTS motor, if it moves- its the control module, if not, its the motor

 

[Dr Honda]

I guess I forgot about this thread... but yes, those are the stock carbs... as you found out. Also, the kits never come with base gaskets, and there isn't a gasket between the top and the airbox. If you made one... that's fine, but you don't need it since there isn't a lot of free floating dirt over the water.

VTS... you are working thought it.


Now as far as the rectifier/regulator... if you are getting 25v out of it REPLACE IT BEFORE YOU ROAST YOUR $500 MPEM or $300 CDI!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


If nothing else... pull the red wire, and go give it a test drive. Even if the high voltage isn't causing the miss fire, its still a problem that needs addressed.

As far as "What voltage does the alternator produce"... I don't know. It's not a spec, or a test that is used. Also... its a 3 phase alternator, so you can't check it with a regular meter anyway. You would need a good linesman meter that could put a load on it, and check phasing. (not normal home tools) If the impedance of the coils is right... then the stator is good. Also... 15v is too high of an output on the regulator. at 5000 rpm, you should see 13.5 to 14.5 volts. Anymore or less than that... replace it.

The 800 engine uses a DC current CDI unit, so if the voltage is out of range, it will do strange things. On an engine like a 720, high voltage doesn't affect the ignition since it uses an HV mag coil, and the MPEM is just a kill signal. (doesn't control timing)

 

[amarzzarella]

Dr Honda,
Thanks for the quick reply. Yes I have disconnected the rectifier, but believe it or not I do have a linemans meter (I am an electrician by trade). My concern is that if the alternator is putting that much voltage out, I might fry another rectifier ($70 locally) giving it a shot. I had read on another older post that someone had the same problem replaced the rectifier and the problem came back. Also you recommend taking it for a test ride with the rectifier disconnected. How long do you think the battery will last? Where I put it in, it's a better than 5 minute ride out of the no wake zone (and back in) and I really don't want to get stranded out in the bay or worse get towed into the thin canal back to the ramp.

Andy

P.S. Where at in Pittsburgh? I grew up in West End and my wife grew up in Beechveiw.

 

[kustomkarl]

The only thing the battery is for is starting the engine, and drawing for other accessories. Do as Dr Honda suggested and see if it helps the problem. If the power output is that high, it can only be the Rectifier, as it is the only component that regulates the voltage, high or low...

Karl

 

[Dr Honda]

If your battery is good... it should run the ski for a couple hours as long as you aren't stopping and starting. But, if you disconnect the red wire from the regulator... you will know pretty quick if it's your problem.

On thing though. Even if you replace the regulator... the CDI or MPEM could already be damaged from the high voltage.

As far as the over voltage from the stator... I don't think that's possible. If the impedance is in spec on a static test... they are within their design parameters. I've never checked myself... but un-loaded, on one phase... you may see 100 vac at high RPM's. When balanced, and loaded, I would think 50 vac or more is possible.


Last thought. On the 800 engine, the pick-up coils are known to break away from their mounts, and cause issues. You may want to open the MAG cover and make sure it's still attached. (it's external of the flywheel)


BTW... I'm in Irwin, and my shop is in Latrobe.

 

[amarzzarella]

OK here's what I got. I checked all my grounds and they were good, cleaned all connections. I replaced the rectifier and checked output prior to hooking it to the ecm. Same output as the previous one. 25v at idle and up to 60v at high rpm. I took the ski out today with rectifier removed and yellow magneto leads taped off. It ran great probably put 4 hours on it and she purred the whole time. So now I am really confused. There is very little chance that I bought a bad rectifier/ regulator. I admit it is possible but very unlikely since the other person did the same on his ski and got the same result that would mean we both got bad rectifiers. Any and all suggestions would be appreciated.

Andy

 

[Dr Honda]

Yes... it's very unlikely that you would get a bad regulator... but it is possible, and we now know thats the problem. With it disconected... it runs.

You mention a second person... was the regulator used?

 

[amarzzarella]

No the regulator wasn't used, but I had found a thread on another site where a guy had the same problem. He didn't discuss regulator output voltages so I'm not quite sure he has the same problem. But all the symptoms were the same. That's what lead me to check output voltage of the regulator. When I replaced the rectifier/regulator, I got the same output as I did with the original. So that's when I decided to just run it without the rectifier. As an update since it ran so well Saturday we took it back out Sunday and ran it another 6-7 hours without charging the battery. When we were done Sunday I checked the battery and it was still 12.53 volts ( I am impressed) so right now I just plan to run without rectifier regulator unless you have anymore ideas that I can check.