RPM's going high.....90hr Evinrude

Jmorrell588 · #1 September 23rd, 2003, 06:45 PM

1989 90hp crossflow V-4

My RPM's at max is right about 4,900. It was hitting 4,900 today until I went back to the ramp. I noticed that it was at 5,700 RPM's at full throttle. What caused (best guess is all I am looking for) this happen and is this something I should worry about? Thanks for your time.

mrtool2u · #2 September 23rd, 2003, 06:49 PM

Did you happen to lose a blade on the prop,,,,,I lost a blade once and I gained a few hundred rpm's,,,just a thought.

Jmorrell588 · #3 September 23rd, 2003, 07:08 PM

MrTool... no that was the first thing I checked. I also checked the hub to insure it was not spinning by starting off from low speed in the water and going to high speed real fast... hub is fine.

Dhadley · #4 September 24th, 2003, 04:48 AM

One good thing is -- thats a lot closer to where the rpms should be. Did you gain any speed? Lose any speed?

Lets start here. Good luck!

jim dozier · #5 September 24th, 2003, 07:17 AM

Did the engine sound different. I would think you could hear an additional 1000 rpms. Certainly if the engine speed increased by 1000 rpms there would be a noticeable speed increase. I'm wondering if your tach was the culprit. Ultimately, like Dhadely says, 5700 rpm is closer to correct than 4700 rpm. For how long have you been running the engine at the "apparent" 4700 rpms?