1992 XP What happened?

[burtshaver2021]

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.

Maybe your compression tester is a little off? And your compression is actually a little better than the 125.

 

[tomski]

That's very possible. Going to try my brother's gauge tomorrow and see where we're at.

 

[travial]

Did you check the timing on the rotary valve? I'd definitely check that to rule it out. Hard to believe it's a compression issue when it just all of a sudden started running like crap.

 

[tomski]

A buddy of mine who has helped me with these over the years, suggested that the flywheel key, for whatever reason, may have sheared. I guess that the inevitable is that this motor will need to be pulled. Redoing the compression check today as well as on the others, to rule out compression as the cause.

Regardless, the older I get, the harder it seems to get on in there and get the job done.

 

[tomski]

Question...so would it be possible that, while I did shut down the fuel supply while trying to start what I assumed was a completely flooded motor, I overwhelmed my motor with oil with zero chance of getting it to run....?

 

[tomski]

BTW....after further review, compression retest reveals a measurement of 135lbs .Both identical .

 

[Venturian1]

You were asked if the engine turned freely after the new wear ring, you replied yes the driveline turned freely.
How much did you rotate it, a couple of turns? with the plugs in, you should have felt the compression.
With the plugs out, it should have turned freely and easily a couple of full turns. All of this turning done with the PTO flywheel.
Did you check the pump alignment?
It should run at 125psi, as long as there's no drag at the pump. may be a bit difficult to start tho.
ground the plug wires and with the plugs out, crank it and blow the fluid out of the crankcases

 

[tomski]

I greatly appreciate your input. I was hoping for a response to what I was referencing in #30 of this thread. Currently, the motor has been pulled and is on the bench.

 

[burtshaver2021]

Question...so would it be possible that, while I did shut down the fuel supply while trying to start what I assumed was a completely flooded motor, I overwhelmed my motor with oil with zero chance of getting it to run....?

No, there’s no chance of getting so much oil in the crankcase that you wouldn’t be able to start it, when you were cranking at idle there’s pretty much no oil being pumped and even when they do become hydro locked with oil, just taking the plugs out and rolling it over will clear the oil sufficiently to get them started.

 

[tomski]

Ok, I can totally understand that. I just want to make it clear that it was running, very rough @idol, but wouldn't let me accelerate, and would die. When I pulled the exhaust, while removing it from the hull,it spilled out some really black, oily watery mess.

 

[burtshaver2021]

I have one like that, a 95 XP. The inner oil seals leak on it a bit, I had gotten it last fall and never got around to looking at it till this summer, cranked it over with the plugs out and blew maybe a half a cup of oil out which seems like a lot more when it’s being misted out the plug holes, when I start it now which is roughly ever week or 2 it will blow a black sludge out the exhaust but runs great.

 

[tomski]

Yes this one ran great too. I just was hoping to understand or have anybody help me to understand, what may have happened to it while simply sitting on the trailer. ( I have ruled out the wear ring replacement job, it turns freely.) Well, the motor is out now so I will probably throw a little $ and time into it and get her running again.

 

[burtshaver2021]

I’m not able to provide much help, except to say I see a lot of threads where people chase there tails for a long time to end up it being a fuel related issue. So when i hear theirs good compression and good spark I usually advise to go through the fuel system, check it for leaks, follow Mikidymac’s carb rebuild thread, make sure the circuits from the pilot jets to carb throat are cleaned well, new needle and seat, check them for leaks, test after all back together. How long did this one sit without running? Was it hydro locked with oil? Did you take plugs out and clear it if it was, try new plugs after that. I wish you the best of luck figuring it out, this is one I’m looking forward to following.

 

[tomski]

So yes now that the engine is out, I'll probably get that new needle and seat for both already rebuilt carbs , go over the rebuild thread, I have the pop off apparatus now so I'll learn how to do that. It only sat a few days on the trailer. Wasn't locked, 1st thing I did after the initial "rough running" episode, was to pull the plugs, remove air intake parts, pinned the throttle open, and run a fan on it overnight to hopefully dry out anything in the case. Next day, ran the same...rough like it needed to clear out but couldn't. I'll post progress.