Thread: Can you solve this riddle?
06-12-2007, 10:02 PM #1
Can you solve this riddle?
First of all I think I know the answer to the riddle and I will post it if someone doesn’t get it within two days.
Here goes: Yesterday my Ultra only ran 63.6mph @ 7,510rpms and it was full of gas. This morning I leveled the engine with a level and I checked my oil level cold as MyKull suggested (thanks a bunch Mike for the great advice)… and he was absolutely correct… I was overfilled with oil from the factory. So I leveled the engine and I drained out almost 2 liters of oil such that the oil level hit the middle dot (between the hash marks). At 5:00 PM this evening I took the ski out for a run and with 2 bars of fuel I ran 64.5mph @ 7,590rpms. I did this exact run in different directions about 4 times and got the same speed. Since I was so low on fuel, I went to the marina and filled the tank. I idled out and as soon as I passed the 5mph buoys I hit the throttle. The ski ran 64.8mph @ 7,590rpms! I couldn’t believe my eyes, so I tried it again and again in different directions and got the same numbers. And yes, I used my Garmin Etrex to measure speed and the weather had not changed and the lake was the same in terms of chop and lake slop. The question is: why should I be going faster with a full tank of fuel as I did and hour earlier with only 2 bars?
This is not a trick question, but a real life situation and I believe it has a reasonable solution. If you solve this, you get an A+ in Performance!
06-12-2007, 10:12 PM #2
- Join Date
- May 2007
- Savannah, GA
2 days ago, I posted saying to check your oil, and you said you did check your oil and it was fine....
Your right, it's a weird riddle....
And if you read your owners manual, you would have known to level the ski since it says it in there.
06-12-2007, 10:23 PM #3
Not really an answer, but seems like you should be turning a few more RPM. What does your boost gauge show?
06-12-2007, 10:33 PM #4
Here is a thought.
Wieght plays a major factor here. To little on the nose and it bounces some scrubbing speed. To much and it plows scrubbing speed. Just the right balance yields a steady nose with good lift will always yield better numbers.
Thus the rider and possitions are cruecial to best top speed numbers. You will learn your boat the more you play with it. You will learn at what position to be at during different levels of fuel.
No one can tell you what works unless they are the same hieght and wieght as you.
Did I get an A?
06-12-2007, 10:43 PM #5
Actually, I did check my oil 2 days ago and I did level my ski. Unfortunately, I must have checked it before the engine had completely cooled down and I leveled the ski based on the rub rail as I we do with our Sea Doo RXTs. Today, I found out that you have to check the Ultra’s oil when the engine is level, not the rub rail! Of course when I did this I got a completely different reading than the other day.
The riddle is not weird. It is a good exercise in common sense. If you really try to solve it I think you may come to the same conclusion that I did.
06-12-2007, 10:47 PM #6
We haven't got our good boost gauge working correctly yet. It is reading negative boost, which we know is boloney. We think there was electrical disturbance from the spark plug wires. We will fix that problem and re-check the boost this weekend. However, the almost useless boost gauge on the dash seems to be reading 11 (one bar over the 10 mark). My speedo is all over the place… today it read 70 and yesterday it was reading 62.
This is a tough lake. I know when I had my 130mph Spectre Cat, people would come here to race me only to find that there 132mph cats would only run 128mph on this lake!
Last edited by Phil; 06-12-2007 at 10:52 PM.
06-12-2007, 10:50 PM #7
I agree with everything you said, but you did not get the A+! I am surprised at you of all people because the solution to the problem actually stairs you in the face if you go to your blog and read the entire section on “Oil Control” which you wrote! This is where I picked up the insight to my solution.
06-12-2007, 10:52 PM #8
Have you tried adjusting the BOV instead of replacing it?
06-12-2007, 10:53 PM #9
- Join Date
- May 2007
- Savannah, GA
Just a thought, but the max rpm on the guage cluster is just when your max speed took place, is that correct?
If so, you might be turning more rpm's than that if you watch your rpm gauge, just not breaking the top speed on the factory speedo at that moment to record it as the max rpm.
06-12-2007, 10:54 PM #10
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