5.7 350 engine Mercrusier 2011 - RPM low issue under a load

[alldodge]

The wiring is in Merc manual 36 and are not able to scan and post do to the sizes. Here is some or some sensors

 

[Kianoushaa]

The wiring is in Merc manual 36 and are not able to scan and post do to the sizes. Here is some or some sensors

Thank you. Now, until you read the error codes, what is the problem of the engine speed not increasing from 2000 to above?

 

[alldodge]

Still hard to tell, not enough info as yet
We know compression is within spec and so is fuel pressure

Assuming the motor use to run fine under load, correct?
If it did what happened when it stopped running good?
What do the plugs look like?

Look at the distributor cap, they are known to give lots of problems. Caps can look fine but have problems.