lack of top end speed on port engine

[mike lennon]

Help, anyone! I have a 1999 310 with the 5.7L 350 Mag fuel injedctors Port engine runs in sync with Starboard Engine until 2500 RPMs. Port engine is maxing out at 3400. New heads, compression is fine in all cylinders, new fuel pump, 38 PSI, new injectors. Timing and plugs and everything is all good too. After lots of $$$, still have the problem. Any ideas what else to check to get another 1000 RPM top end???? Been using this mechanic for 10 years on several boats I own and he is baffled.

Mike
mikelennon96@gmail.com

 

[juma]

Hi,I have been looking at your thread expecting someone to answer because I'm having the same problem (ALSO PORT ENGINE)only that mine goes steady until 3000 RPMS.New plugs and cables,coil,Knock sensor,swap computers between engines,tps,cap,rotor,fuel pump ,fuel filter,and no codes in the scanner,compression ok on all cylinders,timing at 8 btdc.also new aluminum manifolds and risers.Have you fix your problem? I'm going to time the engine to 12 btdc this weekend and test .(at friends mechanic suggestion).

 

[juma]

P.S. My props are 16"x17", clean bottom and cruising between 21/24 knots

 

[ardeprint]

Are there any signs of running rich? (ie. the smell of fuel, fuel rainbows on the water, etc)

On another note, swap distributor caps between engines. If you changed yours, there are some bad once out on the street manufactured around July of this year.

 

[juma]

Update ,new fuel pump since old one died,it got better to 3300RPM ,advance the timing also to 12 degree btdc ,I disconnect the vacum line of the fuel pressure regulator and got it to 3600 RPM but is not going with the power of the starboard engine. apparently the fuel pressure regulator is bad. just receive a new one, expect to get it installed tonight.Any improvement on yours MIKE LENNON. Thanks ARDEPRINT,going to try it just to rule out.

 

[Brad Fraser]

I don't know if anyone is going to see this but, I'm now having the same problem! I've done heads, fuel filters, compression is great, replaced the idle air control valve and still same issue. Have you guys fixed this??? I'm stuck.

 

[Monroe Boater]

Do the throttle control cables need to be adjusted?

 

[Quint4]

Have you cleaned or replaced the filter under the fuel pressure regulator?

 

[Brad Fraser]

Have you cleaned or replaced the filter under the fuel pressure regulator?

You are the second person to mention that little filter. I'm going down tomorrow, is it easy to get at? Is there any precautions I should take before pulling it apart?