Normal idle rpm for GM 305.

[TampaBoater]

Hey guys.
What is the recommended idle rpms for a mercruiser gm 305?

 

[Bondo]

Re: Normal idle rpm for GM 305.

Ayuh,.... Pretty much All of our boat motors idle at 650/ 700 rpms, in gear, in the water,....

 

[alldodge]

Re: Normal idle rpm for GM 305.

Hey guys.
What is the recommended idle rpms for a mercruiser gm 305?

Around 650-700

 

[TampaBoater]

Re: Normal idle rpm for GM 305.

Ok….I guess I have to make some adjustments to mine. I am running around 1000, but not in the water, and not in gear.

 

[NHGuy]

Re: Normal idle rpm for GM 305.

Set it for 700 to 725 neutral idle and it will drop to around 650 in gear.

 

[TampaBoater]

Re: Normal idle rpm for GM 305.

Set it for 700 to 725 neutral idle and it will drop to around 650 in gear.

I have the repair manual, but it goes very vaguely about how to adjust the idle and the carburetor. Does anyone have any good sources to properly set the idle? I have a GM 305 with a mercarb single screw.

 

[Fun Times]

Re: Normal idle rpm for GM 305.

I have the repair manual, but it goes very vaguely about how to adjust the idle and the carburetor. Does anyone have any good sources to properly set the idle? I have a GM 305 with a mercarb single screw.

Hi there, What year is the engine model? Better yet, Do you have the engine serial number handy as well?

 

[TampaBoater]

Re: Normal idle rpm for GM 305.

Hi there, What year is the engine model? Better yet, Do you have the engine serial number handy as well?

Its an 87 mercruiser gm 305 5.0l. The serial I have to get when I get home.

 

[Scott Danforth]

Re: Normal idle rpm for GM 305.

go to the adults only stickies at the top of the forum and download the Mercruiser manual