7.4l idling question

[KnotConnected]

the Merc manual for my 1994 7.4L Bravo 3 says the idle RMP while in forward gear is 650. Does the idle RPM in Neutral change, or should that be at 650 also? I finally got the boat to idle / run by adjusting the idle speed screw, and its sitting at about 550-600 RPM now while in neutral. The RPMs seem to drop a little as the engine warms up after ~half hour of use, so i'm not sure where to set the idle RPM speed at, as I want to avoid dropping it into gear any higher than 650 RPM, but don't want the engine to die while trying to dock it because it's idling too low after its warmed up.

 

[Bondo]

Re: 7.4l idling question

Ayuh,... If it's idlin' in gear, in the water at 650 rpms, it might idle at 650/ 700 in neutral,...

 

[tpenfield]

Re: 7.4l idling question

the Merc manual for my 19947.4L Bravo 3 says the idle RMP while in forward gear is 650. Does the idle RPM in Neutral change, or should that be at 650 also? I finally got the boat to idle / run by adjusting the idle speed screw, and its sitting at about 550-600 RPM now while in neutral. The RPMs seem to drop a little as the engine warms up after ~half hour of use, so i'm not sure where to set the idle RPM speed at, as I want to avoid dropping it into gear any higher than 650 RPM, but don't want the engine to die while trying to dock it because it's idling too low after its warmed up.

Merely putting the outdrive into gear without any change in throttle position will no doubt lower the RPM due to the load now on the engine. My experience with the 7.4 is that it drops very little (maybe 50-100 rpm). My old boat was set fairly low, and as I recall, it would be about 550-600 in neutral and maybe 400 in gear.

My 'new' boat is more like 750 in neutral 650 in gear. I would not worry about shifting the Bravo drive into gear at 750 RPM. It can handle it and then some.