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Thread: 471 marine gm

  1. #1
    Join Date
    Oct 2008
    hobart, tasmania, australia

    Default hi just bought a new crayfishi

    hi just bought a new crayfishing boat which has a 471 gm in it apparantly recond 3 years ago can some one please tell me the oil pressure at idle and cruising which brings me to another problem every one tells me it should rev to 1800 but it will only do 1300 maby over proped but motor wont black smoke at all we cruise at 1100 revs which gives us 8 knots for about 8 litres per hour

  2. #2
    Join Date
    Nov 2008
    Hammond, La, USA

    Default Your 4-71 should have 5 psi of

    Your 4-71 should have 5 psi of oil pressure at idle and 55 psi @ full load-1800rpm. What is your fuel pressure while at full load? Lack of fuel could cause it to lose power without having the engine smoke.

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