1992 XP What happened?

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tomski

tomski

Active Member
Hi guys... so after replacing the wear ring on my jet pump, I went to fire it up before putting it back on it's trailer. For whatever reason, after a uncharacteristic hard start, it started running like the timing was off. Is it possible for the timing to change? It will be running extremely rough, like it is trying to clear itself out, but just doesn't. Plugs very wet. I have had the plugs out, a fan blowing in the open cylinder, with the carburetors wide open trying to just get all the fuel out of the block.
 
Would anyone think that maybe the MPEM box could/would cause this erratic idle. When it's running like it does, it won't accelerate without choking out the motor. It just seems like it is so close to clearing out but just can't get up the r's !!
 
Yes, I can turn the shaft freely. So crazy this ski ran awesome. It just needed the ring replaced
 
Yeah, not sure what could have happened. At this point I think the problem has nothing tp do with the ring replacement. Just a random coincidence. Maybe new spark plugs. If nothing then maybe fuel system. Carb rebuild?
 
I had mentioned taking the plugs out and blowing air in to remove fuel from the crankcase, I agree, I don’t think the wear ring replacement is related to the rough running. If the engine has filled up with some fuel, sounds like the needle or seat may be leaking
 
Yeah I'm pretty positive that it's not a related matter. Just tough to understand how a running machine can start to run like that when just sitting on the trailer for a day or so. Wondering if these motors can go out of time for any reason.
burtshaver2021 said:
I had mentioned taking the plugs out and blowing air in to remove fuel from the crankcase, I agree, I don’t think the wear ring replacement is related to the rough running. If the engine has filled up with some fuel, sounds like the needle or seat may be leaking
Click to expand...
 
tomski said:
Yeah I'm pretty positive that it's not a related matter. Just tough to understand how a running machine can start to run like that when just sitting on the trailer for a day or so. Wondering if these motors can go out of time for any reason.
Click to expand...
No experience with it, but I do definitely remember reading a post from Mikidymac that they don’t just go out of time. Again, not familiar at all, never had one that I had to adjust the timing so ????
 
Might be worth it to check some basics like compression and putting in-line spark monitor on each plug to see if consistent spark.
 
***UPDATE***
Compression for each cylinder was at 125lb. ish( both identical)
Spark is bright and consistent.
Both carbs completely, and I mean completely, dismantled, thoroughly cleaned, and reassembled using Genuine Mikuni rebuild kits.
No changes, still running as it did before.
My last chance I thought would be to switch out the MPEM box from one of my other running '92 skis, to one. Again, no changes.

Is it possible that somehow, this motor may have jumpedaor stripped a tooth on that internal brass sprocket ? Thanks for any other ideas on what to try next.
 
I'm not sure what is normal for a 92XP but 125 might be low. What is the compression on your other running 92?
 
tomski said:
***UPDATE***
Compression for each cylinder was at 125lb. ish( both identical)
Spark is bright and consistent.
Both carbs completely, and I mean completely, dismantled, thoroughly cleaned, and reassembled using Genuine Mikuni rebuild kits.
No changes, still running as it did before.
My last chance I thought would be to switch out the MPEM box from one of my other running '92 skis, to one. Again, no changes.

Is it possible that somehow, this motor may have jumpedaor stripped a tooth on that internal brass sprocket ? Thanks for any other ideas on what to try next.
Click to expand...
If that compression tester is accurate that’s pretty low compression, probably low enough that even if it was running correctly it would most likely have difficulty starting when In the water. You mentioned that you cleaned the carb and rebuilt, where did you purchase the carb rebuild kit from? Did it come with a new needle and seat? Did you check pop off pressure when you rebuilt the carb? Any bubbles /leaks when you were checking pop off? From you previous post mentioning the plugs being wet and you trying to dry the fuel out of the engine it sounds like the needle or seat could be leaking.
 
One things for sure, there is a big benefit to owning more than 1 if the same machine, take the carbs off 1 of your running XP’s,
 
I'm going to check the compression on the other 3 for an average. Over the years, I've ordered at least 8 or so rebuild kits from our local Seadoo dealer. Always the same. Have yet to see one with a new needle and seat. If they manufacturer them, I haven't heard of it. I know this is going to be hard to believe, but with all the work I've ever done on all 5 (yes 5) of these XP's, I have yet to have done this popoff adjustment. I haven't taken the time to figure out how to do it. I understand there are a couple of methods.I know I should do it. I have done these carburetors a lot with a really good success rate. I don't believe that the way this ski is currently running, is a carberation issue.
This machine ran great this summer.
It sat on the trailer with the others.
It needed a new wear ring.
It broke itself.... 💔
 
tomski said:
I'm going to check the compression on the other 3 for an average. Over the years, I've ordered at least 8 or so rebuild kits from our local Seadoo dealer. Always the same. Have yet to see one with a new needle and seat. If they manufacturer them, I haven't heard of it. I know this is going to be hard to believe, but with all the work I've ever done on all 5 (yes 5) of these XP's, I have yet to have done this popoff adjustment. I haven't taken the time to figure out how to do it. I understand there are a couple of methods.I know I should do it. I have done these carburetors a lot with a really good success rate. I don't believe that the way this ski is currently running, is a carberation issue.
This machine ran great this summer.
It sat on the trailer with the others.
It needed a new wear ring.
It broke itself.... 💔
Click to expand...
If you don’t find another issue then you could take the cover and diagram off the metering side of the carb, spray some wd-40 in the needle area saturating it, push down on the needle arm and spray a little in there to, cover the return fitting and the fuel outlet if it’s a dual carb which I’m sure it is on a 92 XP and put some air pressure in the fuel inlet of the carb. Pop off test is actually exactly the same except you need to build yourself a pop off tester which is just a schrader valve, t fitting with a gauge on top and a barbed fitting to run the line to the carb. Actually you don’t even need to take the metering cover off, just put 10 pounds to the carb Inlet and block the other fittings to see if the needle is leaking. Good luck,
 
tomski said:
I'm going to check the compression on the other 3 for an average. Over the years, I've ordered at least 8 or so rebuild kits from our local Seadoo dealer. Always the same. Have yet to see one with a new needle and seat. If they manufacturer them, I haven't heard of it. I know this is going to be hard to believe, but with all the work I've ever done on all 5 (yes 5) of these XP's, I have yet to have done this popoff adjustment. I haven't taken the time to figure out how to do it. I understand there are a couple of methods.I know I should do it. I have done these carburetors a lot with a really good success rate. I don't believe that the way this ski is currently running, is a carberation issue.
This machine ran great this summer.
It sat on the trailer with the others.
It needed a new wear ring.
It broke itself.... 💔
Click to expand...
I order the back to OEM kits from OSD marine, those kits come with new needle, seat and spring. Pop off being incorrect isn’t the Only concern. Just thinking they may be leaking when you mentioned the overly wet plugs and fuel in the engine
 
Thanks for your info on the kits. I'm going to change out these carbs for another set. Hopefully it will rectify the issue. Having my doubts 😕
 
Ok..but I wonder what may have happened, while on the trailer, to have this catastrophic development to the compression. Again, this was a strong running motor.
 
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