97' XP 800 Stalling when accelerating

[1099ezg]

I recently purchased a really sharp looking yellow '97 Seedoo XP 800. I have ridden jetskis a lot in the past, but this is my first jetski that I own. For context, I know quite a bit about car engines and have rebuilt a 2.0t in the past. During my inspection, the jet ski started up right away and revved awesome out of the water.

When we first brought it into the water however we noticed some problems.
1. Blue smoke was coming out of the exhaust badly during the first few mins, it went down later but it was still happening.
2. For the most part, the jetski would only idle normally. I could put the throttle all the way down sometimes and nothing would happen and would be going the same speed. Sometimes it would rev up and start going quickly, but then it would turn off and almost sounded like a whoosh of air was released during the stall. After the stalling it also had trouble just idling.
3. Once we took it out, we noticed some blue oil coming out of the exhaust. There is also some blue oil in the bottom of the hull but was there before we ran it.

The jetski is still premixing, I do not put oil in with the fuel. I thought that maybe the carburetor could be a problem, so I removed that. It looked very clean, like maybe the past user had already cleaned it. I replaced a few parts inside the carbs that I noticed did not look great and also one of the carbs was missing the black hard gasket on the fuel pump....... Guessing the other person forgot to put that back on.

I have not put it back together yet, but I am wondering since the carb looked so clean and there was nothing clogged if this was even the issue. I know a missing gasket is bad and could have been the problem but I am wondering if I need to check anything else before I put everything back together. The plugs looked fouled and I am going to change that as well.

Anything else I should check with those three problems? For the oil, I am guessing that it is being burned and maybe could have been due to the carb but I am also going to put some Lucus stop leak in the oil to see if any internal seals or rings may be damaged as well.

I also have zero clue on the hours this engine has, I got it for an absolute steal and am mechanically inclined so I was not too worried about any potential problems. It also has a aftermarket intake grate and a motorcycle steering wheel from the previous owner.

 

[burtshaver2021]

myself I would start with a compression check to see where I stand ( determine if I want to move forward ) if compression is good ( 130 to 150 and the cylinders are within 6 or 7 pounds I would then go ahead and rebuild the carbs with back to OEM kits from OSD Marine ( osdparts.com ). If you want to try and save some money on the carb rebuild kits you could check the pop off of the needle, after checking the pop off, put the diaphragm back in and cover and pressure test it, also could test the fuel pump side with 4 pounds. Could also verify that the correct jets are in there. Set the high and low speed screws to factory settings. Does it have the original air box and flame arrestor? Test or change the 2 fuel vent check valves. And go from there. Ive tried to save some money by not doing te carb rebuild, hasn’t worked out for me yet, lol. I’ve had to buy the back to OEM kits every time, you could also check the voltage regulator/rectifier by putting a bolt meter on the battery, rev machine to 500”rpm, the volts shouldn’t go above 14. Never had a bad one myself, but I’ve read that they can cause all sorts of problems when they are bad and specifically remember reading of a situation like yours where it ran well out of water but had issues at higher rpms in the water.

 

[1099ezg]

myself I would start with a compression check to see where I stand ( determine if I want to move forward ) if compression is good ( 130 to 150 and the cylinders are within 6 or 7 pounds I would then go ahead and rebuild the carbs with back to OEM kits from OSD Marine ( osdparts.com ). If you want to try and save some money on the carb rebuild kits you could check the pop off of the needle, after checking the pop off, put the diaphragm back in and cover and pressure test it, also could test the fuel pump side with 4 pounds. Could also verify that the correct jets are in there. Set the high and low speed screws to factory settings. Does it have the original air box and flame arrestor? Test or change the 2 fuel vent check valves. And go from there. Ive tried to save some money by not doing te carb rebuild, hasn’t worked out for me yet, lol. I’ve had to buy the back to OEM kits every time, you could also check the voltage regulator/rectifier by putting a bolt meter on the battery, rev machine to 500”rpm, the volts shouldn’t go above 14. Never had a bad one myself, but I’ve read that they can cause all sorts of problems when they are bad and specifically remember reading of a situation like yours where it ran well out of water but had issues at higher rpms in the water.

I already went in and replaced a few gaskets and stuff on the carb using a Mikuni kit. Not sure how great those are compared to OEM. The carb insides were very clean. I opened the high and low speed screws and replaced the orings and put them back to where they were. How do I know what the factory settings are supposed to be? I think it was about 7-8 turns for both carbs. It also does have the original air box and flame arrestor.

Sometimes it wouldnt even rev any RPMS above idle with my hand on the throttle, but when it did it only did it briefly before stalling. I will check out the check valves too as I saw some other people stating that could be the case. I also did not check under the jetski to see if anything is stuck but im guessing if it revved up in the water even for a few seconds there probably isnt anything clogged down there. I will check though before I try again.

And that is interesting about the voltage regulator, I will have to check that as well.

 

[burtshaver2021]

Sea Doo PWC Carburetor Reference
From what I see here the 97XP low speed screw should be out 1 3/4 turns from closed and the high speed screw should be closed, 0 turns out. Low speed screw would have a T handle I think ancc dc the high speed screw has a plastic cap you have to take off before you can adjust it, a pair of needle nose will work to pull it off. Don’t close the high or low screws hard, just lightly closed. There’s a real good thread on rebuilding the carbs on here I can attach if you like? Even if you don’t fully rebuild them, it’s a super handy thread

 

[burtshaver2021]

the regulating side of the carb is responsible for fueling up to 1/4 throttle. You could also take jets out, put the low speed screw in a turn or so and spray some carb cleaner in where the jets screw in, you should see some fluid coming out the 3 holes in the carb throat when the choke plate is opened. It’s all explained better in the carb rebuild thread.

 

[Grim]

One thing I would check is if the cable to the oil system is off. The system will go wide open if the cable is off/broke, with all that smoke it sounds like it could be. Did you reconnect it when you reinstalled the carbs. Also you said you rebuilt the carbs, did you check the pop off and do a leak check?

 

[JJinSC]

That model also has accelerator pump for carbs. Function test it to make sure diaphragm is good, check valves are working and nozzles in carb throat is spraying.

 

[1099ezg]

I rebuilt the carb and replaced the diaphrams and cleaned out the nozzles. I tried messing with the low speed screws and high but it still is not working. It will accelerate great for about 5 seconds the first time of the day we get it into the water than we cant get it to go again. Its no longer stalling after some carb tuning, but it will not go past about 20mph with full throttle down.

Could it be a fuel filter clog? Rave valves? Ignition coils? I replaced the plugs so I know its not that. The throttle cable is good as well. I am only getting small white smoke coming out now as well.

 

[Grim]

I would replace the filter if you don't know how old it is. Also have you cleaned the raves? They are easy to take apart and clean, you can verify that they slide well too. If you don't have history with the engine I would get a rebuild kit for the raves too. Have you checked that your rectifier is working. All you do is put a multimeter on your battery and rev up the motor, the voltage should start in the 12vs but cimb into the13s maybe low 14s when you rev it up.. Check your book for the exact numbers. (you can dl the book for free online) If you hit the 15s or higher you have issue , if you stay in the 12s you have issues.

I would also set the low and high speed screws to factory and not mess with them. That is something you really have to know about to make it work outside those setting, normally it is used if you have racing parts and other aftermarket kits. IMO There is a sticky thread that tells you all about those setting if you want to read up on it.

Does your buzzer work? Are you getting any beeps?

 

[1099ezg]

I would replace the filter if you don't know how old it is. Also have you cleaned the raves? They are easy to take apart and clean, you can verify that they slide well too. If you don't have history with the engine I would get a rebuild kit for the raves too. Have you checked that your rectifier is working. All you do is put a multimeter on your battery and rev up the motor, the voltage should start in the 12vs but cimb into the13s maybe low 14s when you rev it up.. Check your book for the exact numbers. (you can dl the book for free online) If you hit the 15s or higher you have issue , if you stay in the 12s you have issues.

I would also set the low and high speed screws to factory and not mess with them. That is something you really have to know about to make it work outside those setting, normally it is used if you have racing parts and other aftermarket kits. IMO There is a sticky thread that tells you all about those setting if you want to read up on it.

Does your buzzer work? Are you getting any beeps?

There is definitely a LOT of aftermarket parts on it, such as a modified intake grate, motorcycle steering wheel, and who knows what else. So I brought the low a little closer to 1/2 to 1 turn. With the low speed out more it felt like I was burning oil and it was overheating and sounding worse (More hiccups and misfires when trying to rev up). It is really hard to adjust the carbs and to keep them aligned together with the screws under the carb and I feel like I cut my hand up so much doing it, but i do not really want to take it completely off again. I feel like it would at least somewhat work if the carb screws were barely off but I do not know. I feel like since its sounding good at low speeds now unless i put my hand on then throttle and then it hiccups a bit like its trying to go fast but just cant. Its just odd it never wants to kick to high gear, making me think something is blocking the flow of fuel so I will definitely replace the filter and filter housing.

I will have to check the rectifier I did not know that could cause problems like this. Also, no, I have zero beeps or buzzes and my gauges dont work either. The previous owner left some spare parts with me and it looks like he changed the MPEM out. I am just getting tired of diagnosing this and there are zero shops or dealers around me that will still work on these two strokes. I haven't touched the raves at all yet, so I will look into them as well.

I am not sure if this is related but I saw some blue oil coming out of the prop/jet housing in the back when we were putting it back into storage. None inside the engine bay or through the exhaust and no blue smoke as far as I have seen recently.

 

[Grim]

Do you know if it is an aftermarket MPEM, those are notorious for being unreliable.
The blue oil might be the two stroke oil. I think mine is bluish, . Also don't mix 2 stroke oil, they don't always like each other, And use the right type.
As far as fuel supply, you could put a hose on the carb and in a container of gas/premix, that would eliminate all the parts in the gas supply chain, if you are running good then you got a filter, selector valve or tank baffle issue.
I'm no guru on the rectifier but I have read where people have problems at higher RPMs when the rectifier isn't working right. Search on this forum and see if they match your issue in any regards, there are a lot of threads on rectifiers.