RPM at idle

[WadmalawJoe]

This site is awesome. The wealth of knowledge shared on here is priceless.
What I would like an opinion on is my 2000 Johnson 50 hp (2-stroke,vro removed) that runs great. The Teleflex tachometer that came on my boat was not hooked up but, I was told it worked just needed to be hooked up. I used the information that I gathered on here. I connected the purple, grey and black up accordingly and set the tach on 6p. At the first start up and run (on muffs) it read 3000 rpm at idle, which it was not. So I shut it off,adjusted the adjustment screw on the back off the tach, eventually as far as it would go. It now reads 1200-1300 rpms until it warms up then goes down to 1100 rpm and stays there steady. It should read 800-900 rpm should it not? Is it running a little faster being that it is just on muffs and not in water, or is the tach off a little? It sounds completely normal as far as rpms go.
Thanks for your input it is greatly appreciated, by me and many,many others out there.

 

[wilde1j]

Re: RPM at idle

Idle is set in the water, in gear and should be ~ 650 RPM.

 

[WadmalawJoe]

Re: RPM at idle

Thanks Jim,
I will see if I have a garbage can or something that will fit around the motor and fill it with water for a test tank and see what I get then. I am thinking the tach is off a little. I just don't think the rpm's will drop that much setting it in water but I'll see what happens.

 

[jonesg]

Re: RPM at idle

Mine idles at 1100 on the hose, drops to 700 in the water in neutral.
Thats a 400 rpm drop.

 

[WadmalawJoe]

Re: RPM at idle

My motor did the same. I set up a test tank (clean trash can) and rpm's dropped in the water. I was relieved, not only does the tach work and reads accurate, my motor is running good.
Changing my foot oil and installing a GPS/fishfinder today. Hopefully fishing as well.

Thanks for your input Jim and Jones!