View Full Version : Rpm @ Wot
09-02-2007, 10:26 AM
Anyone remember where that thread was posted, My 94 PS 190 with EFI 350 turns 5600 RPM's. That seems way to high and wanted to check that post.
Finally got around to checking my boat. I am running 5600 rpms at wot. 43 mph, gps checked. The boat seems to run great. lots of power, great hole shot. I think I am running a 14 X 18 prop. I am sure I have the power slot. Does this seem possible? Is there a rev limiter? EFI 350, all stock, as far as I know.
09-02-2007, 10:33 AM
Yes, that seems WAY too high....
09-02-2007, 11:24 AM
If you check your manual, it'll tell you what max rpm's you should be at. 5600 sounds pretty high. I have the ACME 541 prop on a '97 prostar 205and run 44mps @ 4400 rpm, WOT.
I'll be interested in this info as well.
My mechanic once told me that the general rule of thumb for small blocks is around 5500. Right or wrong, that has been my reference point ever since. In my experience, most stock engines begin to suffer valve float or other problems above that, and most seem to be cammed/timed to peak below that. What I mean is that they don't seem to develop more power as you climb above 5000 or 5300 RPM, at least not with stock breathing, valve train and cam.
I would also love to know what Velvet Drive says about the max RPM on their drives?
Is your engine stock?
09-02-2007, 11:59 AM
The MasterCraft owner's manual for your boat specifies WOT for your engine at 5000 RPM. I suspect you're way underpropped.
09-03-2007, 11:44 PM
Double checked today. prop is 14 x 18, wot is 5600. can the tach be wrong?
09-04-2007, 12:49 AM
Double checked today. prop is 14 x 18, wot is 5600. can the tach be wrong?Yes, it can. With a 14x18, the tach being wrong seems most likely. See if you can borrow a handheld digital tach, or go buy one, or take it to your dealer have them check it. In the meantime, check all the wiring, especially grounds, associated with that instrument.
09-04-2007, 01:37 PM
Thanks for the advice, I will try that first. I am also trying to borrow a different 14 x 18 to see if that is the problem. Can anyone confirm for me that this is the correct size prop.
09-04-2007, 01:49 PM
94 LT1 here wot is 4800 rpm and about 48 mph