Thread: RPM's DOWN~~WHAT TO LOOK FOR ?
08-21-2008, 07:51 AM #1
RPM's DOWN~~WHAT TO LOOK FOR ?
Set up is:
* Riva Through Hull Exhaust
* Riva 3" Tube Intake
* 13/19 Solas Screw
* 2' Wedge
* Riva Grate
* Metal S/C Washers
* RRacing 133' Thermo
* Nopas Block Offs
70.5mph @ 7940 RPM (not that GR8 IMO)
was 8040 @ 70.8 before Exhaust System
Already checked for any Ex. Leaks~~~None found
Oil Level was checked Cold @ 1/2 between crook marks on stick on a level trailer.
Any suggextions are appreciated.....
Last edited by David_HX_RXP; 08-21-2008 at 07:52 AM. Reason: correction
08-21-2008, 07:52 AM #2
08-21-2008, 07:57 AM #3
08-21-2008, 07:57 AM #4
Hi David, 100 RPM's isn't that much of a drop and could easily be caused by heat fade. If you are ever out riding and get max RPM's and then after an hour or so your RPM's drop down 100 RPM's or so this is heat fade.
Over filled oil could also easily rob 100 RPM's. I see you checked your oil while the engine was cold.
The proper oil check method is as followed
With a hot engine, let it idle for 30 seconds
Shut the engine off and wait 30 seconds
Check the oil
You want the oil level mid way between the two bends on the stick.
08-21-2008, 08:01 AM #5
It was about 91' yesterday but that is why I bought the RRacing Thermo, to give my best shot to avoid the heat fade issue.
Will re-check the oil w/ a hot engine today.
Expecting the same air/water temps....
With the aforementioned Mods. I was sort of expecting approx. 71+ @ 8000+
Maybe a repitch is needed (???)
Thx for the fast responce.
08-21-2008, 08:27 AM #6
did you suck anything up? that happened to my ski so i reached in the intake grate and sure enough i pulled a bunch of crap out and got my RPM's back
08-21-2008, 10:14 AM #7
08-22-2008, 06:33 AM #8
Good call !
Looked up into the intake tract and noticed the Billet Sleeve which screws onto the nose of the Impeller had backed off and was 1.5" down on the Driveshaft.
That also probably accounts for the new found water being forced into the hull through the Carbon Seal. (backpressure)
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