Two stroke oil pump operation??

[Ankeneyou]

Did you ever figure out the oil injection line issue? I'm having the same problem on my XP. If i hold the injection pump to full at idle it pumps just fine and clears any air. As soon as I gun it to full throttle, large air gaps appear in both lines (too big to just be bubbles). Just replaced both lines with tygon and had fully bled them before taking the ski out. Zip tied both and they are secure to the pump. I'm just glad I was watching them with the seat off so I didn't cause damage.

Not trying to hijack your thread, just hoping you got a resolution since this popped up in my search. I've got a questionable 787 in the basement i may just rob the pump from.

 

[JJinSC]

I wanted to address a couple of points. 1) if everything is working properly, idling 15 to 20 minutes should not hurt these engines. 2). If you are seeing air bubbles in the lines, either you are not bled completely or you have an air leak somewhere in the supply line or a pump seal. That is simply a matter of physics. No air, then it is impossible to have bubbles.

If you are not seeing oil leak out anywhere and sitting in the hull/bilge or ruining down outside of a line then it is probably a pump seal issue. Replace pump. Replace filter while you are at it.


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[Sportster-2001-951C-Stock]

The replacement small oil lines should be 3/32" ID, what size are you guys using?

 

[Ankeneyou]

3/32 tygon. I have no oil leaks anywhere and no bubbles at all in the supply line. I'm going to replace supply line, oil filter, swap pumps and hope one of those resolves the issue.

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[Ankeneyou]

I replaced all as stated above and found the root cause. The pressed in fitting in the oil pump was so loose it fell right out when I removed the pump. I'm hoping this isn't a common occurance. If I hadn't changed the injection lines and watched them closely on the first trip it likely would have cost me an engine.

 

[Sportster-2001-951C-Stock]

Great feedback! Ah yes, and now I recall this has happened before.

The outlet fittings are press fit as well.

These may have been epoxied in and so it's likely many will fail. Amazing it wasn't leaking oil into the bilge!

 

[jimmaki]

I replaced all as stated above and found the root cause. The pressed in fitting in the oil pump was so loose it fell right out when I removed the pump. I'm hoping this isn't a common occurance. If I hadn't changed the injection lines and watched them closely on the first trip it likely would have cost me an engine.

Glad you pulled the pump and found that loose fitting! Sometimes just changing the injection lines will show up a loose fitting as you pull and push on the tubing or tighten the tie wrap clamps. Your spring looks fine from what I can see. A big mirror helps getting the pump back on.

 

[JJinSC]

Yep, that happened to mine during break-in of a rebuilt engine. I found mine in the hull with most of my oil. Fortunately, I still had premix in the tank for break in. PTL!

I have heard of at least two other accounts since. I'm glad you found this before it actually fell out.


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[Ankeneyou]

I have to thank everyone here for all the great info. If it wasn't for this site I would have never changed the injection lines so wouldn't have seen the issue. My old lines were still original and painted so I would have been clueless. Thanks everyone for saving my engine!

On the plus side, I now have an additional item on my ski inspection checklist!

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