787 engine spewing oil from PTO cylinder plug hole

[Rdessewffy]

It was running fine before hydrolocked. When engine filled with water I turned it over until nothing came out plug holes and then pulled engine from ski. I took off the cans and sprayed everything I had
into the bottom end....fogging oil, WD40, T9(my favorite). I turned crank and kept spraying and draining while tilting engine until I felt like there was no more moisture in it.I put it all back together after a couple days then started it and ran good in driveway. I then let it sit for many months until now and went to crank it up and it fired for a split second. I took plugs out and cranked it over and PTO cylinder spewed oil all over. I kept cranking it several times and oil didn't seem to be getting any less and didnt want to ruin anything so here I am now not knowing what to do. My first thought was just pull engine all the way down and split bottom end. I Googled issue and found several posts where people just keep cranking until oil is out and then all is good, but that doesn't seem right to me. I dont have a problem pulling engine and rebuilding if needed, but if there is a chance I dont need to , of course I want to know about it. Thanks for any suggestions.

 

[AKnarrowback]

Inner seal on the crank is leaking oil from the rotary valve shaft chamber into the case. Very common.

Interesting that the motor did not have this problem prior to getting hydrolocked. Just guessing but it sounds like maybe some seal damage might have been done in the process.

There are some "fixes" for this scenario, but the sudden appearance is standing out as a red flag. If it had no oil problems prior to the water incident I would take the motor down and check the seals. One of the fixes requires splitting the case anyhow.

 

[JeremyD615]

Yes, it’s almost certainly the inner crank seal. Sometimes they will leak like that after sitting for a long period and will then “plump back up” once you get it running and heat cycle the motor a few times, but I’d be concerned that it’s filling so quickly. I’d probably try to get it to fire up and run it if the weather is still warm enough where you’re at, just to see if it will clear up. If the season is already over though, I’d order a new crank and start tearing it down...

 

[Rdessewffy]

I'm going to pull it rather than try to start it. My press is 20 ton not 50 and wouldn't feel up to the challenge lining everything up any way, so if it turns out to be inner seal I will buy crank. I'm sure once I pull engine and split bottom I'll have more questions, so thanks to both of you for reply. Hopefully I can put it on dolly in garage today and disassemble tomorrow. THANKS!

 

[Rdessewffy]

I pulled engine and split case. Evidently the previous owner installed a new crankshaft as I can see the welds. They must have had a hard time lining up the two halves on re assembly because I see two nicks on inner seals which tells me they pushed too hard then tried again and forced them together. I'm thinking I can save this thing if I trim off the little dangling rubber that may have let oil pass..... nicks seem to be lower than where the seals would sit in the grooves of the case. Maybe a little sealer of some kind too?? What do you think? I dont mind pulling it apart again if it doesn't work to try and save $350..... the ski always smoked a lot and now I know why.... im going to replace rotary shaft seal and counter balance seals ( one was shredded) , I also want to put new rings in because I may have ever so slightly bent one being careless. The top of piston has a stamp 1.50 on it, I Googled and cant figure out which replacement rings to get. Any info on ring size would be great. When I got the ski I knew the guy put new pistons and rings in it but never knew the crank was new. Thanks!

 

[mikidymac]

Looks like a SBT crank. They weld theirs.

Does that crank have rust on it?

You are going to have to rebuild the balancer and replace it’s seals.

Typically it’s the inside lip of the crankshaft seals leaking not the outside diameter. I would be surprised if those nicks let that much oil leak but without pressure testing it’s hard to tell.

 

[Rdessewffy]

Looks like a SBT crank. They weld theirs.

Does that crank have rust on it?

You are going to have to rebuild the balancer and replace it’s seals.

Typically it’s the inside lip of the crankshaft seals leaking not the outside diameter. I would be surprised if those nicks let that much oil leak but without pressure testing it’s hard to tell.

No rust on crank and bearings spin free with no noise, its definitely cherry and I was very surprised. Counterbalance bearings good too, I ordered the seals though. I thought same thing about leakage, but figure its the dangling part that let oil pass. I can see by pulling everything apart that quality parts were used, but for some reason they were careless putting it together..... I did not pressure test and would have to Google how to. I rebuilt another engine with new SBT crank and never pressure tested but its fine. Its actually pretty cool to pull it all apart and see exactly what happened when you don't know the complete history, like CSI Sea Doo lol.... any idea on ring size part of my post? Thank you, I always get good responses from you!

 

[mikidymac]

You will have to determine what brand of pistons they are to get the correct rings. Size is 1.50mm over. It sure sounds like a full SBT rebuild. I know they bore stuff out pretty big.