96 XP--so close after lots of work, please help

[acbprop]

got 96 XP, started and ran but bogged down (but kept running) once you got up and running. Wouldn't stay on plane. Had original hoses. Replaced them and gunked up filters, cleaned selector, rebuilt carbs, cleaned up RAVE valves, even removed fuel tank and cleaned it. Now it starts, but any throttle and it immediately stops running. Went back through all hoses, selector, even took carbs off and went through again. Still does same thing. So it's worse than before.

Last night, pulled rear plug boot and it kept running. Hmm. Pulled front boot and it quit. Swapped plugs, and pull either boot and it quit. So maybe a bad plug? Replace both plugs today. Pull either boot and it stops. Cut back wire 1/4" as suggested other places and no improvement. 150 psi compression both cylinders.

Any ideas? The main things I've worked on have been carbs, hoses and the RAVE valves (though I did that before the hoses and it was running as original--don't think that's screwed up). Any suggestions? Does the weird plug thing last night mean anything?

 

[D 5UPE]

Check the choke isn't jambed on.Could be over fueling.
Are your plugs soaking wet with fuel when it dies, or on start up?
Those carbs have diaphragms which work via crankcase preasure. Could be a holed diaphragm. Check the hoses from cranckcase to carbs. Lets know how you get on.

 

[acbprop]

Choke is working fine. But it does feel like over fueling.

Plugs appear to be wetter than they should be.

Diaphrams are both new from rebuild kits.

The hose that goes from the crankcase to the mag carb appears fine. Put new hose clamp on the carb end to be sure.

I really appreciate your help. I feel like there's something simple I've overlooked.

 

[D 5UPE]

Did you reuse fuel after cleaning the tank.
If so could be dodgy fuel or lost its octane.
I know you have poor octane fuel over there 85 ron
we use 95 ron over here and it lasts longer in the tank than 85.

 

[acbprop]

completely removed the tank, all new fuel. When I first ran it and it was running better than it is now, it was actually with a mixture of very old fuel and some new fuel. so I don't think it's bad fuel or low octane.

 

[JDC]

Had the same problem with my 98 SPX after I rebuilt it. Idled fine, then bogged down and would quit running all together, when I tried to take off.


Took the carbs back off, read the thread about the "insides of an 800" and took the accelerator pump apart and cleaned it. It was sticking bad.

Went through the shop manual on how to tune the carbs, (high/low settings, cable settings, etc)

Synced it with the oil pump, and then set the idle screw in place, the thing ran great today, NO BOG!

I don't know if this helps, you said you went through the carbs, but maybe tearing the accelerator pump will be the ticket.

JD

 

[timmyboy76]

did you replace the internal springs of the carbs, with the ones from the rebuild kit?

 

[acbprop]

Not sure what the accelerator pump is. or synch with oil pump. could you elaborate?

Settings-wise, I put everything back to original. The high speed screw was all the way in, the low speed was 1 turn out. Put all cables back to original. Nothing else to adjust, is there?

The springs on the popoff valves: I used the old ones, because the kits came with two silver colored and two goldish colored. And I lost one of the silver color, so I figured it would be best to re-use the old ones, because they seemed ok. Mistake there? I might be able to find the other silver colored one. also, my first "rebuild" I didn't even mess with the popoff valve--just gaskets and diaphrams. The second time, I did more through job replacing the popoff parts and the running conditions are the same.

I did not test the popoff pressure before and after--beyond my abilities. But I did make sure the lever was level.

Thanks you guys for all the help.

 

[JDC]

Yeah, I did not rebuild my carbs, just cleaned everything out.

The accelerator pump is a small pump on the side of the pto carb. It pumps in a small amount of fuel to give you the burst of power to get you going. The pump itself is pretty simple. Just a diaphragm and some springs. Mine was tight, and not releasing well. Took it apart, cleaned it, and greased the piston on it. The back of the piston that goes through the diaphragm and pushes it was a little rusty, so cleaned that as well.

Then set it. There is a set screw. I believe you are to back it off till there is a small gap on piston and arm, then screw it back until the arm touches the piston on the pump. When pulling the throttle, the rocker on the carb itself come in contact with the accel pump arm, causing it to push the piston and pump fuel into the carbs, again just at the start to get rid of that bog.

The "sticky" on the seadoo main thread describes the accel pump and what it does, pretty well.

Syncing the oil pump, it should not have much to do with your power problem, but is crucial if you have disconnected the throttle cable and oiler cable.....

To sync it, you need a small mirror, like a dental mirror. On the oil pump, there are indexing marks. On on the stationary part, and one on the rocker that the cable is connected to. At NO throttle at all (ldle) these marks must line up. This ensures that oil is going in at the start, and more importantly, that at full throttle, as much oil is needed is going into the engine.

Mine was off about a quarter of the way. Lucky for me, I was running premix to break my motor in. I stumbled across the oil pump sync in the section on setting the carbs in the shop manual, and jumped to it and about fell over. I am glad I caught it.

Hope that helps, or at least gets you on the road to some help,


JD

 

[acbprop]

That doesn't sound familiar. Do I have an accelerator pump on my motor?

 

[acbprop]

Looking at those pictures, I don't believe I have an accelerator pump. That agrees with some other threads.

 

[JDC]

Bummer, I am not sure what carb set ups have them.

I don't know where to go from here, the accel pump solved my bog problem, hopefully someone on here can help you go from here.


Good luck on getting it running, let me know if there is something else I can help you with,


JD

 

[acbprop]

I'm wondering if Timmyboy could comment on the spring issue, which I replied to earlier.