2004 XLT 800: Smoke in Engine Compartment

[raymond90]

Need some experienced advice. I am not familiar with 2 stroke engines, especially in Waverunners. Just bought 2 used Waverunners. I am having an issue with one where it will start(only with wide open throttle) and run(poorly) and the engine compartment fills with what seems like exhaust smoke. I cannot tell where the smoke is coming from.

I have already removed the exhaust joint and chamber assembly. They do not look cracked, not sure how to tell if the gaskets are bad visually. There is no soot around the joints. The rubber hose connecting the exhaust chamber to the water lock was tight.

The smoke seems like it is coming from the bottom of the engine or on the carburetor side of the engine. Any ideas how the exhaust could be escaping there or what to check? I read that the crank seal could be bad or the crankcase could have a hole in it. Not sure how that could leak exhaust though. I would think that only intake air mixed with fuel and oil would escape there. I am going to pull the engine tonight hopefully and see what I can find.

Also, when I was flushing water through it while the engine was running, the bilge filled up and turned black like it was mixing with oil. Engine did not try to cut off but I shut it off because it didn't look good.

[Technical Support]

Re: 2004 XLT 800: Smoke in Engine Compartment

you need too check the water box all connections and hoses for cracks and breaks

[raymond90]

Re: 2004 XLT 800: Smoke in Engine Compartment

Pulled and disassembled engine. Pics are attached. Any ideas what caused all this damage? The Power valves appeared to be broken off and are no where to be found. There was a lot of oil in the one broken cylinder. Is it possible that the injector put to much oil into the one cylinder? Water? Or power valves?

I am getting a rebuilt engine so I don't want to have the same failure.

[raymond90]

Re: 2004 XLT 800: Smoke in Engine Compartment

Well, I got the engine rebuilt by pwcengines.com. Would not recommend that to anyone because it took over 4 weeks, they sent me the wrong engine, and when I finally got it the flywheel housing was dented in and the water fitting on the head was crushed in. The guy that rebuilt the engine said that wasn't a big deal and he would sent me the water fitting so I could replace it(he never sent it). FYI the fitting is pressed in and can be removed by heating up the head.

After overcoming those setbacks, finally got the engine installed and rebuilt the carbs using aftermarket kits which were missing o-rings for the high and low speed adjustment screws. Put it all back together using the original o-rings(mistake). Set the screws to spec. Could not get the engine to idle below 1500-2000 rpms and I noticed some rpm surging around 6300 rpms. Engine seemed to lack power full rpms and speed. I used it like this for the break-in period and a few rides but then decided to replace the o-rings. Once the o-rings were replaced, the engine now idles at 1100 rpms but the surge at high rpm and lack of full power is still there. Confirmed that the power valves are functioning correctly with seat off on the water. Also confirmed that they are not broken or scraping the piston by using a borescope through the spark plug hole and moving the lever. When i take off from a stop to WOT the engine rpms will rise to 7000 and stay there for a few seconds till it gets to about 15 mph and starts to plane. Then it drops down to around 5000 rpms and the power valve opens momentarily. The rpms then gradually rise back up to around 6500 where it surges and drops a few hundred rpms. Power valves seemed to be closed. I can get the pwc up to 46 mph on smooth water, but it doesn't have anywhere near the power of the other waverunner(same model).

Noticed that oil has been accumulating in the hull slowly. Pulled the exhaust bellows and found that the rear carb was wet with oil on the top and bottom. The bottom of the exhaust bellow also has oil splashed up on it. Not sure where the oil is coming from. Tried running the engine and looking for leaks, no sign. I had already removed the oil pump and run premix. Plan to replace the fuel hoses and the pulse hoses. Maybe this will correct the leak and surging and lack of full power. Let me know if you guys have any ideas. I have also replaced spark plugs and I am considering replacing the spark plug wires or at least trimming and re crimping. I read some post that said this fixed a similar problem. Also read that changing the pop off pressure springs could fix this as well. But I though pop-off pressure only affects low rpms and throttle? Anyways, figured I would share what I have learned so far. Its hard to get answers sometimes.

[SBT-Tech 1]

Re: 2004 XLT 800: Smoke in Engine Compartment

Pictures indicate a lean condition. Possibly a crank seal. I would have sent the engine back for the warranty. I guess there is no chance of that now that it has been disassembled. You will need to rebuild that engine or order up a new one. I would go through the carburetors again.
XL 800: ShopSBT.com

[raymond90]

Re: 2004 XLT 800: Smoke in Engine Compartment

Those pictures were from when I first bought the ski and found the problem. I have since had it rebuilt and am just working on getting it to run properly at high rpm. My questions are:

1. Does popoff pressure affect high rpms? For example if the spring tension was to high, would it limit the fuel delivery at WOT.
2. What else would cause the engine to surge at 6500 rpms and not reach 7000?

[SBT-Tech 1]

Re: 2004 XLT 800: Smoke in Engine Compartment

If you are getting to 6500 RPM's the needle and seat is open, which means the carb has already "popped off". The fuel pump portion of the carb may not be working to its max, or possibly a restiction in fuel delivery.