Oil pump problems

[Robj]

Oil pump problems...help please

Hello,

Well with the help of Chester, we fired up my 1997 GS with a newly rebuilt 720 engine from SES. The engine ran great, but one of the clear oil injection lines was not pumping oil, it was filled with air. The other side was pumping fine. I did replace both oil injection check valves, and we think that one of them is faulty and letting oil flow back through. It did pump up fine when we turned the pump with a drill, but soon as we installed it and ran the motor, the one oil line was filled with air and did not inject any oil into the cylinder. Anyone have any other ideas? I would like to keep the injection system intact and rather fix the problem than run premix. Luckily I am running a 50:1 mix so the cylinder that did not get the oil was still adequately lubricated.

Thanks and have a great day,

Rob.

 

[LouDoo]

What does Chester say? You got one of the best guys on the forum helping you. Did you bleed the pump and injection lines?

Lou

 

[Robj]

You are right Chester is one of the best. He has never seen this type of problem before. He thinks it is the check valve just wanted to see if anyone has any other suggestions. Finally got a nice day and the seadoo is sitting in the garage. Oh well. Have new check valve on order and hopefully that will fix it.

 

[Thumper3322]

What happens when you are at idle and you turn the pump to full on? It should send oil then. Your connections tight on the pump side? If not (via zip ties went thru that bs today), you will get air in there. But with full on at idle you can see oil going thru it.

 

[Robj]

Yep with the pump full open there was air in the line, it was not pumping on one side. My guess is check valves. Maybe someone else has some suggestions.

 

[Thumper3322]

Air and oil, or just air?

What did you secure it with? I'm asking to help and to see for myself. Had similar issue today, but seemed to be I couldn't get the zip ties tight enough, so put another one around them and seems to have fixed it.

 

[Robj]

The zip ties have nothing to do with my problem. The lines after the checkvalve see positive pressure, no suction. If the zip ties were the problem then the oil would leak out. The oil seems to be flowing back into the pump through the faulty check valve, hence the air in the line.

 

[Dr Honda]

I would make sure the screws on the top are all tight. Then... I would make sure the check vlave, and nipple are both clear.

It's the second time we've heard this... this summer.

 

[griz400]

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[Robj]

Thanks for the replies. While I could have easily goofed up, I had Chester check things over and he could not figure it out either. I do not think it is a faulty pump, I still think it is the check valve which is why I am only seeing air on one side. If it were the pump there would be air on both sides, I think? Thanks for all the help, greatly appreciated. I will get it figured out.

 

[Robj]

Anyone else have any suggestions?? They are greatly appreciated.

Have a great day.

 

[Thumper3322]

Borrow a pump from Chester or someone and try.

 

[mikidymac]

My guess would be the check valve like you suspected. The pump seems to be ok but it only takes a small piece of junk to stick the check valve and they will fail in the closed position. You have one on order so just wait and see if that solves it. You could go to the trouble of swapping your used chcek valves now and see if the blocked line follows the bad check valve just to confirm.

 

[Robj]

I asked Chester and he did not have one. If I understood better how that pump works I would be more comfortable with my decision. Does the pump need a properly functioning check valve to pump? I see how the oil flows back because the valve failed open, but cannot understand why the pump cannot pump oil in that line once the engine is started.

 

[mikidymac]

Not sure of the exact internal of the pump but seeing as your line will not fill I would assume the valve failed in the closed not open position as you have stated. The oil can not "flow back" into the pump either because it can not overcome the pressure of the tank above the pump. Also if the valve was default open it could potentially drain into the engine at rest. I know of situations on the 787 motor that has the check valve on the rotary cover and not the pump have stuck closed and fried an engine. Swap the check valves like I suggested to make sure if you want.

 

[One40ozBUICK]

Ok. I need to jump in and ask a question. Sorry if I need to start another post . Let me know if i should... I have a 98 GS as well that sat with gas for a year or two. I drained it cleared the lines and filter and drained the gas tank. New gas in it. How do I check if the oil is pumping or if it clogged or does it even get clogged?

 

[mikidymac]

These pumps almost never fail or get clogged, this is somewhat of a isolated incident. There is asection of the oil line that was not painted so that you can see the oil through the clear tube. Take a look at the tube and just make sure there is oil in it. Sometimes it is hard to see because the oil stains the tube but a piece of white paper inder the clear section can make it more visable. Another way is to start the ski and let it idle and use your finger to pull the oil pump lever to full open and watch the exhaust. After a few seconds you should see more smoke indicating that the oil pump is supplying too much oil at idle because you are giving it full oil by hand.

 

[LouDoo]

I've pretty much missed the weekend, we've been at the lake. I haven't made any comment except my initial one at the beginning of this thread. I keep thinking how nice it would be to have someone like Chester or Dr Honda help me with my ski's. Anyway I really don't have any suggestions except wait for the check valve to arrive and see if it works.

The comment that I would like to make is this is another reason to change the injector lines, of course the primary reason is because the lines get brittle, and break, deprive the engine of oil and you get a roasted engine. If the oil lines had not been changed to tygon lines this problem would have never been diagnosed, same result roasted engine.

There is not reason not to change these lines it's a relatively easy job, I've found it easier just to remove the carbs. you don't even need to remove the cables, just lay the carbs. in the hull.

Getting off my soapbox now.

Lou

 

[Robj]

Yep it was great to have Chesters help. You are right we would have never spotted this problem with the old lines. Funny thing is that with the drill the pump seemed to work fine. When running the engine that is when there was only air in the line. Glad I had premixed the fuel as well so there is no damage done, just need to get it fixed.

Thanks for all the replies and tips.

Have a great day.

 

[RodInEscondido]

I have been inspecting and cleaning up stuff on my 89 SP project and this might help (I will put pics on that post when I get them):

For the oil check valves I took a syringe (you all should have one in your tackle box for pumping a bit of air in night crawlers), attached a short piece of the tygon oil line to it (remove the needle first), connected the check valve and dipped it in a small jar of solvent. You can then draw some solvent thru the check valve to check its operation and clean it at the same time. Draw some air thru it to get rid of the solvent.

Rod

 

[Robj]

Well I just got a new check valve installed and it fixed the problem. No more air in oil line and the system now seems to be working like it should. Probably the biggest lesson learned is to get rid of those painted oil lines and replace them with clear ones, that way if there is a problem with the oil injection system, you can see it before it toasts your engine.

Have a great day,

Rob.

 

[Thumper3322]

Maybe a dumb question, but what exactly is the check valve in the oil pump. Not what does it do, but where is it located? I thought the pump came as one piece and you can't get internal parts for it.