Correct engine idle and top end RPM

[4youngbergs]

Engines idle at different speeds; 1 @1500, 1 @1700. I believe they should be around 1200. How do I adjust and what should they be?
My high end does not match either, and the cables need to be adjusted to the same length. I would like them to be the same length and top end RPM.
Thanks for your help, Craig

 

[Seadeals]

The engines are controlled by the ECM through the cables and should not be different unless (a rare instance) they are not both on the stops at idle. The RPM gauges are analog and can have some error, so trust them less than the actual sound. If you have a true difference, check that levers move the cable at the speed transducer on the engine bay sidewalls from stop to stop. It would be unusual if they didn’t. 1500 RPM is normal for idle. You can see some fluctuation (1500-1800), especially if plugs get old or you are out of the water on the hose with no resistance on the impellers.

 

[4youngbergs]

thanks that is helpful. I know my cables are not the same. one stops and one goes inches past. I will buy a manual and get it figured out.

so ture about the analog gadges, and I'm not positive how much they are off but I can hear one running faster than the other, and the boat does not track stright at idle making harder to load.

 

[Seadeals]

(Port side)
So at idle, the left side in photo is contacting the stop (silver touching dark gray with arrow) so ECM should have a null (idle) input. You can even see a little slack in the cable. At full throttle, the silver tab with the green spring hits the dark gray tab in the bottom of the photo. That sends the ECM to max RPM limit. Everything in between is a potentiometer input (resistance) to the ECM to vary rpm between idle and max. Check here first. If that isn’t the culprit, investigating impeller p/n and condition or engine health (plugs/compression/injectors) may be appropriate. I had one engine always read 8500 at WOT versus 8000; but a YDS read proved it was turning right at 8000. They always sounded the same despite the indicated rpm split. A new tach reduced that significantly; but it sounds like yours could be more.