bouncing rpms on 1 engine

captpaulcaptpaul Member Posts: 41 ✭✭
in Engine Discussions
2005 fiesta vee 300 with twin merc and bravo 3's...gets up on plane at 3200-3300rpm with no problem. as crusing, port engine rpm drops off approx 300-350rpm for 20-30 seconds and them re-surges back to desired rpm. this happens every couple of minutes. this does not occur at lower rpms...runs steady at desired rpm. fuel filters all clean and no alarm beeps. any thoughts....  
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Comments

  • 212rowboat212rowboat Member Posts: 2,593 ✭✭✭✭✭
    check and clean both spark arrestors/air filters.  

    get a gauge on the offending engines fuel rail and monitor if there is a drop in pressure when this occurs.  it should be steady throughout range.   
    click here for faults (BEEP) list
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  • aero3113aero3113 Member Posts: 9,045 ✭✭✭✭✭
    Could be a ground or voltage issue also. I had an issue when the trim tabs were used my engine RPM would surge. I replaced the batteries that were 5 years old and a corroded ring terminal that was on the ground wire to the alternator. Issue went away, not sure which one cured it!
    2008 330EC
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  • frenchshipfrenchship Member Posts: 1,079 ✭✭✭
    Looks like Faria gauge also call tap gauge. If you tap with your finger on the glass of the gauge it should go back to normal.That said I take that the engine stay running properly 
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