1998 GTX Limited Oil Pump Output

[val-e-vue]

After rebuilding the engines in two 1998 GTX Limited skis, I had them at a camp on Lake Champlain for 3 weeks. During that time I pre-mixed the fuel at 40:1 to be on the safe side. I filled the oil injection tank on both machines on day 1 and proceeded to keep track of the fuel I burned in each machine. After the second week I totaled up the fuel burned, refilled the oil injection tanks to see how much oil had been delivered. Here are my results:

Ski #1:
Fuel usage: 40.5 gallons
Oil usage: 78 oz
Fuel:Oil Ratio: 67:1

Ski #2:
Fuel usage: 43.5 gallons
Oil usage: 52 oz
Fuel:Oil Ratio: 107:1

Clearly, I'm thrilled that I pre-mixed ski #2. I'm not so sure about ski #1. I have not found good documentation on this other than the shop manual provides a good procedure for testing the pump at 1500 RPM with pump at full open position (0.83 - 1.01 ml each port).

Any experience with measuring oil usage vs fuel usage?

I think I should take the pump and carb adapters off both machines and bench test. Of course I will be challenged to find the actual RPM of my drill motor. It looks like the pumps are linear because they say you can double the RPM and you should get double the oil. You don't find much information related to rebuilding the pump, so I would guess the focus might be on cleaning the nozzle (check valve) and hope that gets the flow rate back to normal.

Thanks, Gregg

 

[mikidymac]

As long as your alignment marks on the oil pump are set correctly you will be fine.
These skis use a variable rate oil pump so the usage really depends on how they are ridden and can vary greatly just on different riders. At wide open throttle they are around 32:1 and at idle over 100:1 so depending on how you ride it can be very different.

 

[Chester]

You're overthinking it.

Chester

 

[val-e-vue]

As long as your alignment marks on the oil pump are set correctly you will be fine.
These skis use a variable rate oil pump so the usage really depends on how they are ridden and can vary greatly just on different riders. At wide open throttle they are around 32:1 and at idle over 100:1 so depending on how you ride it can be very different.

Thank you!! I guess I was not trusting enough... I could just see all the hard work turning into scrap metal

Gregg

 

[Mraw]

Seadoo oil pumps are super reliable dont worry

 

[val-e-vue]

Trying to live up to the "over thinking it" motto! Here is the test stand my brother built. The far right bracket holds the pump fully open. The middle bracket holds the pump zero'd with the hatch marks aligned.

We did some testing today. All tests were performed at 1500 RPM on the "Ski #1" system.
Zero'd: No flow, not a single drip for 5 minutes. Repeated this test multiple times.
Full Open: 2 ml/min This meets the shop manual spec.

We ran some follow-on tests and found that the pump only needed to be adjust slightly above the "zero" position and it would start producing a drip periodically. I plan to adjust to the positive side at idle to avoid running without lubrication. If I were the only rider, idling wouldn't be a problem but you never know.

These results are from "Ski #1" which provided the following empirical results. We will test "Ski #2" once we get this one put back together and moved out of the garage.

Ski #1:
Fuel usage: 40.5 gallons
Oil usage: 78 oz
Fuel:Oil Ratio: 67:1

Gregg

 

[POPPS]

You're overthinking it.

Chester

Chester...my exact thoughts.,,,there are far greater issues to be solved on skis than the oil useage.

 

[thelederfam]

What other ways are there to confirm that oil is being injected into the engine? I have a 1997 GTI. While preparing to rebuild my carb I decided to confirm if the system was pumping oil. I haven't used the ski that much due to the engine running purely which hopefully will be solved with the carb rebuild and the new gas lines. It does smoke at idle but I don't know if that means much. The engine has never stopped due to overtemp and I think the oil tank level has been reduced with use but not by much. I found that no oil dripped out when I removed the bleeder bolt! Oil would pass thru the oil filter though. The lines are so dark and dirty it's hard to even see if there is air in the lines. I filled the line and bled it. The 2 little lines appear to be filled with oil. I ran the ski and held open the valve to add more oil to the engine and monitored the smoke output. I really couldn't tell for sure if it smoked anymore that when I don't hold the valve open and let it work with the throttle. Could I have caused the air in the line by pressure testing the oil tank system per the manual's instructions earlier in the day?

Would a valid test be to remove 1 of the 3/32" oil lines at a time to watch or measure the oil output with the engine running? This seems a lot easier than removing everything to run the pump with a drill. To prevent damage to the engine during this test I would mix oil in the gas. I could buy a tach to monitor the engine RPM during this test.

 

[Mraw]

What other ways are there to confirm that oil is being injected into the engine? I have a 1997 GTI. While preparing to rebuild my carb I decided to confirm if the system was pumping oil. I haven't used the ski that much due to the engine running purely which hopefully will be solved with the carb rebuild and the new gas lines. It does smoke at idle but I don't know if that means much. The engine has never stopped due to overtemp and I think the oil tank level has been reduced with use but not by much. I found that no oil dripped out when I removed the bleeder bolt! Oil would pass thru the oil filter though. The lines are so dark and dirty it's hard to even see if there is air in the lines. I filled the line and bled it. The 2 little lines appear to be filled with oil. I ran the ski and held open the valve to add more oil to the engine and monitored the smoke output. I really couldn't tell for sure if it smoked anymore that when I don't hold the valve open and let it work with the throttle. Could I have caused the air in the line by pressure testing the oil tank system per the manual's instructions earlier in the day?

Would a valid test be to remove 1 of the 3/32" oil lines at a time to watch or measure the oil output with the engine running? This seems a lot easier than removing everything to run the pump with a drill. To prevent damage to the engine during this test I would mix oil in the gas. I could buy a tach to monitor the engine RPM during this test.

Seadoo oil pumps are bullet proof. When you opened the bleeder screw there should be a slow consistent amount of oil comming out. Then hold the pump lever wide open, you should notice slightly more smoke than usual but it can be hard to tell. Make sure the little 3/32 oil lines have no cracks as over time they get brittle. These skis use very little oil so don't worry about the tank not going down much. If you really want to then yes you can remove the lines and make sure oil is pumping through. The engine will idle at 3000 RPM on land so if you are not in the water then pre mix a little bit of fuel. I really wouldn't get all caught up worrying about the oil pump, bleed it and be done.

 

[val-e-vue]

What other ways are there to confirm that oil is being injected into the engine? I have a 1997 GTI. While preparing to rebuild my carb I decided to confirm if the system was pumping oil. I haven't used the ski that much due to the engine running purely which hopefully will be solved with the carb rebuild and the new gas lines. It does smoke at idle but I don't know if that means much. The engine has never stopped due to overtemp and I think the oil tank level has been reduced with use but not by much. I found that no oil dripped out when I removed the bleeder bolt! Oil would pass thru the oil filter though. The lines are so dark and dirty it's hard to even see if there is air in the lines. I filled the line and bled it. The 2 little lines appear to be filled with oil. I ran the ski and held open the valve to add more oil to the engine and monitored the smoke output. I really couldn't tell for sure if it smoked anymore that when I don't hold the valve open and let it work with the throttle. Could I have caused the air in the line by pressure testing the oil tank system per the manual's instructions earlier in the day?

Would a valid test be to remove 1 of the 3/32" oil lines at a time to watch or measure the oil output with the engine running? This seems a lot easier than removing everything to run the pump with a drill. To prevent damage to the engine during this test I would mix oil in the gas. I could buy a tach to monitor the engine RPM during this test.

Both of my skis have the 951 motor and they were both blown up when I bought them. So in my mind I was not being overly cautious to verify the oil systems. Clearly we have people here that are much more experienced and they have proven to themselves over the year that the pumps are bullet proof. I appreciate that but still wanted to do my own study and if nothing else, become familiar with the system and develop my own confidence.

I must say, it has been a good education. I have completed the first system and returned it to the ski and taken it out on the water. I will start the second one today, using the same procedure. Three things I learned on the first system: 1) The check valve on the tank was plugged. I suspect this happens over the years as the check valve takes on oil from over filling and combines the oil with water moisture. Granted the pump doesn't require a large vent because it pumps slowly, but it needs something. 2) Lining up the two hash marks on the pump puts the pump in complete shutoff. I'm anxious to see if this repeats with the second ski and I do have a 3rd pump I will test. The first photo shows where my pump started to displace oil. Notice that it is quite far beyond the zero hash mark. 3) The full throttle oil usage was right on target and max. The 2nd photo shows the pump position at full throttle. I found that moving the pump cam beyond this has no effect on output. In other words, max output is reached well before the pump hard stop. No surprise... just good design.

I will compare the other two pumps and see if they are consistent. In my mind, this is a subject worth "over thinking". It seems to me that too many of these engines come to a grinding halt.

 

[mikidymac]

Keep in mind that at idle these skis require almost zero oil. So even though you think it is putting out no oil with the marks aligned there is still a small amount and that is all these engines need.
I understand you want to learn and are being meticulous but you really are over thinking this. If your engine hasn't locked up within the first few minutes of running on the oil injection then the system is working.

Aslo 99.9% of engine seizures on these are caused by lack of fuel not lack of oil.

 

[alkiseadoo]

I must be one of the few that has had their 951 oil pump fail; fortunately it leaked oil into the bilge and I saw it before starting. After having trouble trying to fix it I just blocked it off and have been running 40:1 premix all summer. Yes I used more oil but I must say I'm still on the same set of plugs and have not really noticed much smoke as I thought I would have. Note mine is the carburetor model

 

[val-e-vue]

Keep in mind that at idle these skis require almost zero oil. So even though you think it is putting out no oil with the marks aligned there is still a small amount and that is all these engines need.
I understand you want to learn and are being meticulous but you really are over thinking this. If your engine hasn't locked up within the first few minutes of running on the oil injection then the system is working.

Aslo 99.9% of engine seizures on these are caused by lack of fuel not lack of oil.

Hi Miki, I appreciate your experience and confidence. These are my first skis ever. Bare with me as I learn. I think of this forum as a good place to get some coaching. Believe me I am not discounting what you are telling me but I like to learn and experimenting and collecting data is part of that process.

Re. "Keep in mind that at idle these skis require almost zero oil."
What would you say is "almost zero"? Would you be willing to venture a guess in ml/hr or drops/min? I ask because I have run two pumps now with the hash marks aligned for 5 mins multiple times without a single drop of oil. I have more data that I will post this evening regarding my test results on the 2nd pump. It behaves quite different from the 1st one. Even the full throttle rate is very different.

Thanks,
Gregg

 

[val-e-vue]

I must be one of the few that has had their 951 oil pump fail; fortunately it leaked oil into the bilge and I saw it before starting. After having trouble trying to fix it I just blocked it off and have been running 40:1 premix all summer. Yes I used more oil but I must say I'm still on the same set of plugs and have not really noticed much smoke as I thought I would have. Note mine is the carburetor model

Yeah I have been running 40:1 pre mix in parallel with running my pump (aka belt and suspenders). I have to say, I am very impressed with the XPS oil because it's not smokey at all.

I love the challenge of keeping things stock, so I haven't given upon the injection pump, but I will be 100% confident in my pump before backing off on pre-mix.

I appreciate your input! I was feeling alone LOL.

 

[val-e-vue]

Today I removed the entire oil injection system from ski #2. This is the one that was using the least amount of oil on the water. I had calculated a fuel to oil ratio of 107:1. I was pre-mixing the gas at 40:1 to avoid any damage, so it was a safe experiment.

Ski #2:
Fuel usage: 43.5 gallons
Oil usage: 52 oz
Fuel:Oil Ratio: 107:1

All tests were run at 1500 RPM. Each photo represents a different throttle position as I was searching for the point where the pump actually starts delivering oil. If I don't see oil for 5 minutes, I consider that "no oil". At that point I would adjust the pump cable to a more open position, take a photo and run a test to record the rate.

Photo 1: Normal zero with hash marks aligned.
Result: "no oil"

Photo 2: Cam cutout aligned with hash mark. I found this to be a good zero setting for ski #1 as it would produce a drop every 30 secs.
Result: "no oil"

Photo 3: Cam completely hiding the stationary hash mark post. I'm guessing but this would be in the range of 2500 RPM if you were in the water.
Result: Mag: 3 drops PTO: 0 drops (in 3 mins)

Photo 4: Cam hiding larger Mikuni post.This might be 3000 RPM on the water.
Result: one drop every 6-7 secs on both Mag and PTO

No Photo: Full Throttle
Result: 1.5 ml/min This is slightly below the specification (1.66 - 2.02 ml/min). Ski #1 output for full throttle was closer to the high end of the spec at 2 ml/min.

Conclusion: This pump needs replacing. It would have ruined my freshly rebuilt engine if I had not pre-mixed. No oil until 3000 RPM - yikes! BTW - The pump adjusting cam doesn't move smoothly. When I operate it by hand I can feel a slight mechanical bind.

Next Steps: My brother bought a pump on eBay that he used to layout the test board. I will test that pump and see if it could be a replacement for ski #2.

Thanks,

Gregg

 

[TJG358]

Have to taken the pump apart to look for obvious signs of wear or defects? How do oil pump gears look?
There is a lot info on these pumps ins the Ski Doo Forum .

 

[val-e-vue]

Have to taken the pump apart to look for obvious signs of wear or defects? How do oil pump gears look?
There is a lot info on these pumps ins the Ski Doo Forum .

If you could point me to that info, I would check it out. I took the bracket off the pump from ski #2 after it failed the test. It looked like I would have to pull a pressed in pin to get the adjuster out. I stopped there until I had more information. Since that pump will definitely get scrapped, I will do a full examination as time permits.

 

[val-e-vue]

I completed testing of the pump my brother bought on eBay. I substituted the pump into the the test setup without changing anything else. Still using tank, manifolds, and hoses from ski #2.

Photo 1: Normal zero with hash marks aligned.
Result: 20 secs/drop
0.35 ml/min

Photo 2: Cam cutout aligned with hash mark. I found this to be a good zero setting for ski #1 as it would produce a drop every 30 secs.
Result: 5 secs/drop
0.60 ml/min

Photo 3: Full Throttle
Result: 2 ml/min

I consider this to be the golden pump and it will get installed in ski #2. It does confirm that the pump in ski #1 has some signs of wear since it doesn't output any oil when the zero hash marks are aligned. I have compensated for that by advancing the pump. I will start looking for a replacement, since it may be on it's way out.

 

[WhiskeyD]

Interesting, thanks for sharing.

 

[thelederfam]

I was rebuilding my carb so I decided to try to confirm that the engine was getting oil. I haven't used the ski (97 GTI 720) that much since buying it and see little change in the oil tank level and since it doesn't smoke very much I am concerned. I bled the line, changed the oil filter and pressure tested it but I am still skeptical that it is working. I did advance the oil setting past the hash mark to get more oil into the engine during idle. I don't see oil moving through the 2 small lines and when I advance the oil valve connected to the throttle I don't see any more smoke while running it at idle or higher rpms. I don't want to take the carb off again and mess with testing the oil pump if I don't have to. Instead I added oil from the oil tank to the gas tank for approximately a 40:1 ratio. ( is that oil OK for mixing with the gas?) Then I removed 1 oil line at a time from the engine, plugged the engine port to keep the engine running smooth and watched for oil output. I saw none from either line at idle or a slightly higher rpm for about 1 minute.

I know this isn't the official way to test the oil pump but does is sound like I have a problem?

 

[Mraw]

I was rebuilding my carb so I decided to try to confirm that the engine was getting oil. I haven't used the ski (97 GTI 720) that much since buying it and see little change in the oil tank level and since it doesn't smoke very much I am concerned. I bled the line, changed the oil filter and pressure tested it but I am still skeptical that it is working. I did advance the oil setting past the hash mark to get more oil into the engine during idle. I don't see oil moving through the 2 small lines and when I advance the oil valve connected to the throttle I don't see any more smoke while running it at idle or higher rpms. I don't want to take the carb off again and mess with testing the oil pump if I don't have to. Instead I added oil from the oil tank to the gas tank for approximately a 40:1 ratio. ( is that oil OK for mixing with the gas?) Then I removed 1 oil line at a time from the engine, plugged the engine port to keep the engine running smooth and watched for oil output. I saw none from either line at idle or a slightly higher rpm for about 1 minute.

I know this isn't the official way to test the oil pump but does is sound like I have a problem?

No it does not, the oil pump pumps very little oil at idle. After each ride you won't notice the level dropping that much. You said that you ran it at higher rpms before pre mixing, if so then your pump is working, if it wasn't your engine would have died very quickly.

 

[val-e-vue]

If I were you, I would pre-mix 40:1 until you can confirm that your oil injection pump works correctly.

Testing the system in place seems reasonable as long as you can remove the small hoses and reinstall when you finished.

Pull both small lines from the injectors and put them in a bottle. Hold the injection pump cable at full throttle while engine is idling. This will be the fastest way to purge air from the system.

At idle you should see a drip from each line every 15 - 30 secs. I would be very concerned if you don't see a drip in a minute.

Normal zero with hash marks aligned.
15 - 30 secs/drop
0.5 ml/min per hose (This is an estimate based on empirical data from a 951 pump and using a rate factor for the 720 pump)

Hold the oil injection pump cable at full throttle while engine runs at idle. Drip rate will be too fast to count, but expect 2.5 - 3.0 ml/min per hose.
Full Throttle
2.5 - 3.0 ml/min per hose (This is straight from your shop manual)

Bottom line: Run pre-mix until you are confident the pump is working to spec.

Regards, Gregg

 

[thelederfam]

Gregg, thanks for the info from your testing. Strange how on this forum you can get wildly varying comments/suggestions. It baffles me how I can run the ski without overtemp or lock up without premixing yet I see no oil out of the oil lines. I want to remove the oil pump for a closer inspection. How much effort is it and anything to watch out for. I have already had the carb out so I can repeat that but don't know what to expect with the oil pump. thanks.

 

[Mraw]

Gregg, thanks for the info from your testing. Strange how on this forum you can get wildly varying comments/suggestions. It baffles me how I can run the ski without overtemp or lock up without premixing yet I see no oil out of the oil lines. I want to remove the oil pump for a closer inspection. How much effort is it and anything to watch out for. I have already had the carb out so I can repeat that but don't know what to expect with the oil pump. thanks.

The oil pump is held in by two hex bolts. If it was never taken off before the main supply line will have an oetiker clamp on it, you can use a small flat head to pry the tab off.

 

[thelederfam]

Won't I have to first remove the intake manifold from the engine and then the pump gear to remove the pump from the intake manifold?