96 XP 787 stalls and locks within seconds

[wilbird287]

Hey guys,

I've got a 96 XP with the 787 which I just bought last season. I stored, and winterized (did the same procedure on a GTX also with the 787 which is fine) for the winter. This summer the XP's cylinders were filled with oil and the engine hydro locked. I spent some time reading on the forums and see this is a common problem either caused by bad check valves on the oil injection lines, or bad RV seals.

Either way, I tried "pumping" the oil out which worked, put new plugs in, fired it up. It started up and ran for about 7 seconds and stalled out. When I tried to start it up, the solenoid clicked and the starter motor engaged but wouldn't turn it over. I checked and cleaned electrical connections, everything was good. (FYI- this was a brand new battery I bought this year and installed after I used the old one for pumping out oil.)

I suspected it was more oil which made it's way into the cylinders again, so I pulled the plugs and they were fouled with oil. So I went ahead to try to blow out more oil but nothing came out.

If I waited about 15-30 minutes it would start again, but stall just as quick (tried a few times with variation; letting it idle as well as trying to give it some gas). Every time it stalls after about 10 seconds and the plugs come out dirty, and then the engine won't turn over. (but no excess oil in the cylinders)

Any ideas? I'm suspecting this one is in need of some major work...

Thanks guys (and so far this place has been a great source of info!)
--Will

 

[seadooya]

nah, just alot of oil still in case and on/around everything. Think a few more fire ups, and it'll clear out. Mark the oil resivoir tank, then take a look in the morning, see if level dropped.

 

[wilbird287]

Thats what I thought until I tried to clear out the oil and nothing came out...

So the only thing to do is just clean the plugs, wait 30 minutes and start it again (then repeat all afternoon?)

How many times should it take to get it running properly? I had it run and stall 4 times monday, but haven't worked on it since.

Also- I didn't mark the tank, but if it's leaking quick I'll certainly know if the next time I'm working on it the oil is shooting out again. I'll try mark the tank as well today.

Thanks
--Will

 

[seadooya]

wats compression at? Gone thru carbs yet?

 

[wilbird287]

I honestly haven't taken a look a the carbs yet...ran out of light monday.

I was planning since last year to do the fuel system overhaul so next time I have a chance to work on the machine I'm going to replace fuel lines and do that repair on the fuel sending unit (dead fuel gauge). I'll take a look/clean the carbs as necessary at that point too.

Thanks for the tips so far...but I'm still stumped why it won't turn over after stalling...

--Will

(Don't own a compression tester...altho I guess I should...)

 

[wilbird287]

Finally got some good weather today so I got out to work on the XP. Oil level didn't move, and the first thing I did was try to see if more oil filled the cylinders but none came out when I cranked with the plugs out.

Then I replaced all the grey fuel lines, cleaned and checked the filters (they were good).

I had bought a compression tester, so next I threw that on the MAG cylinder and it climbed steady up to 150 then slowly increased to 180, at which point oil began to appear out of the empty PTO cylinder hole...this result was repeatable. I didn't test the PTO cylinder for fear of pumping oil up into the compression tester gauge.

Any thoughts? Im stumped...why is there oil coming out of the PTO cylinder only when there is pressure in the MAG cylinder, and why is MAG pressure so high?

Thanks,
--Will

 

[voodoo]

Place the plug cables onto the holder and crank the engine with both plugs out, put in a coffee shop spoon of gas in each hole, screw the plugs back in and see if it starts up, let it burn out the oil then test the compression, 150 is ideal.

 

[wilbird287]

Place the plug cables onto the holder and crank the engine with both plugs out, put in a coffee shop spoon of gas in each hole, screw the plugs back in and see if it starts up, let it burn out the oil then test the compression, 150 is ideal.

Please read the initial post...I've already been able to start it normally without extra help or sprays or gas several times (I'd say 8 at this point).

The issue is that 5 seconds after starting the engine stalls and is completely locked (won't turn over like a hydro lock) until I remove the plugs and turn it over with the plugs out. This process of "clearing" out the engine ("clearing" in quotes because there is no oil coming out when i'm cranking with plugs removed), replacing plugs, starting, running for 5 seconds and stalling, can be repeated over and over again with no variation, and no improvement in running time.

The new data I just added is that it seems when there is pressure in the MAG cylinder (my compression tester) and the engine is turning over with the plug out of the PTO cylinder, oil comes out of the PTO cylinder...but no oil comes out of either when both plug holes are open...

I have a feeling something else other than just a little bit of oil being in the cylinders is going on here, and I'm hoping one of the mechanic guru's here can help me out...

--Will

 

[norman504]

It doesn't take much to lock it up. I was amazed today when i fired up my gts for the first time in three years that I only had to pull the plugs twice. I used to spend three to four hours continously pulling, cleaning, burning and replacing plugs before the thing would stay running. when you crank it with the plugs out you won't necessarily get massive amounts of oil, just a light mist. If it still wont run after say 30 times then i would say you might have another problem. don't bother waiting 30 minutes just clean the plugs and fire it right back up.

I don't know why this happens, glad to know I'm not the only one. I even installed a shutoff valve on the oil line and it still fills up over the winter. I'm not an expert by any means, just my experience with my machine. I hope this helps a little

 

[wilbird287]

I think it's time to wave the white flag...after 4 days of working on this, pulling and cleaning various parts, and still having it lock up, I think it's time for professional help.

Could anyone recommend a good tech/mechanic that's familiar with the 787's around the NYC area?

--Will

 

[seadooya]

Will, with the amount of oil present, i'd say, your seals are shot, which means, time for new crank assy.

Depending on which route you go, i'll buy the used pistons off you?

 

[wilbird287]

Decided to sell it whole...

See it here:
http://www.seadooforum.com/showthread.php?p=142180#post142180

Thanks to everyone who helped,
--Will