Proper max RPM - 84 Merc 120

[jeffbrinkerhoff]

I have an 84 Merc 120 in a glastron x-19. With the stock prop (14x19) I max out at 4100RPM and an indicated 34mph (gauge, not GPS).

Is this the proper max RPM? I cannot find the documentation anywhere, and I have searched the internet for what it should be. I assume its probably supposed to be somewhere around 4200-4400 or so.

The engine seems to idle a little rough, but run good (a little hard to start, but after 1-2 minute warm up its fine). I will check the timing this weekend, is 8deg BTDC considered the correct setting now?

Thanks-
Jeff

 

[180shabah]

Re: Proper max RPM - 84 Merc 120

All of those questions are covered in a factory service manual - it is required reading for DIY.

You need manual number 3. Head up to the adults only section to get it.