1992 Manual 305

Has anyone else been having problems with their tachometer? Something is very wrong with mine, although I don't think its the actual unit anymore, as I just replaced the tach with another used one I bought off ebay, and I'm having the same problem. The displayed RPMs are just too high. I idle somewhere around 1200 and in 5th I read 5500 RPM at 55 miles an hour. The engine speed is nowhere near what the tach says.

Just wondering if anyone's ever encountered a similar problem, and if and how they fixed it.

 

i have the exact problem but mines is more exaggerated as when i just rev it up alittle bit and it and the rpms fly all the way to 7000rpms. i dont know how to fix it so i just leave it alone