Mercury 175 rpm problem!

[Ryds600]

Hi, Can I maybe have some advice to solve my problem?

I have a Mercury 175 Black Max 1995 with rpm problem.
Is was a sunny day and the motor was running fine. Suddenly the day after the problem started. I was running at 5200rpm suddenly the motor started to ?jump? and acting as an engine with out sufficient amount of gas. When I reduced the throttle to 1000rpm the motor running fine. But now it is impossibly to get more then 3000rpm. And the boat can`t level out. If I try to push the engine it will just jerk and act as it get not enough gas. Any suggestions ?

 

[Faztbullet]

Re: Mercury 175 rpm problem!

Check the basics first...compression,spark then fuel system

 

[Ryds600]

Re: Mercury 175 rpm problem!

As you say Faztbullet basics first. So.. 1. Comp. OK. 2. Spark on all six, OK. Fuel system not ok. Find that water separate filter was a big problem. Have now cleaned the fuel system and changed all fuel filter. But still same problem. Only different I find after this is that the motor start more easy. Also tried to disconnect alarm module for oil and temp. Still same problem. All six injection nozzles have similar flow.
Question, can some one give me references for tolerance on nozzle flow and fuel pump pressure for this motor ? And what shall I do now ?

 

[Ryds600]

Re: Mercury 175 rpm problem!

As you say Faztbullet basics first. So.. 1. Comp. OK. 2. Spark on all six, OK. Fuel system not ok. Find that water separate filter was a big problem. Have now cleaned the fuel system and changed all fuel filter. But still same problem. Only different I find after this is that the motor start more easy. Also tried to disconnect alarm module for oil and temp. Still same problem. All six injection nozzles have similar flow.
Question, can some one give me references for tolerance on nozzle flow and fuel pump pressure for this motor ? And what shall I do now ?

Measuring from mec. service Fuel nozzle flow 248-250 cc and pump pressure 40psi.
Are this value OK ?