RPM Meter varies

[CJmesk]

Example, If I am at 3200 rpms without changing speeds it will bounce up to 4200 and back down. No skier just cruising.

Any suggestions on what the problem is?

[apexeon]

My '97 Response does the same thing. I have the standard Mercruiser 350 mag carb engine. Strange thing is my perfect pass RPM shows the correct RPM. I suspect a faulty Tach. I'm interested to hear what others have to say.

[mrothwell]

I had this issue on my '97 Echelon. In my case, the contacts on the tach were somewhat corroded. I pulled the tach, and on the back there is a switch that changes the tach from a 4/6/8 cylinder. I moved that switch between positions several times to clean the contacts, then made sure I put it back on 8 cylinder. That took care of the problem. This happened a year following an incident of my speedo air tube coming off the back of my speedometer and flushing the back of my dash with water. So, I figure that I got some water up in my tach and that corroded the contacts. It's a cheap easy fix, if it's the same issue.

[jklein]

I had the same problem and fixed it the same way as mRothwell.

[JeffK]

CJMesk - Did that fix it? Are you still seeing the problem?

[wienrdog]

Third here with the same problem.... Fixed the same way as MRothwell... At least I think that's what fixed it.. I did lots of other fixes/maintenance at the same time, but that was the only one related to the tach.

[mrothwell]

I have patented that fix. I will now be collecting royalties from everyone that has used it.

Hey, if CC can collect royalties for the tower, I should be able to collect for this.