Merc 525 help???
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Merc 525 help???
I have a 525 efi motor is poping under a load and has no power. i switched out the computers theres no difference fuel pressure is 40psi did anyone had this problem before please help thanks..
#2
I don't know the spec but that fuel pressure seems low. I would expect around 55. Lean mixture can cause a backfire through the intake. But I would guess you have a burned or dropped valve. Possible due to the lean mixture if I'm right about the fuel pressure.
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40 sounds about right the specks are normaly 38 psi with vac hose on and 43 hose pulled off. still pull off you fuel filter and dump it in a glass jar or a clean coffee can and look for water or dirt. also check the ground cables to the batteries and engines make shur they are tight and clean. Was this your first run this year after sitting ? could be some left over old gas.
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If it's only doing it under a load, then start looking at the ignition system. Check the coils to be sure they are all getting power. Also, check all of the plug wires real good. Pull the plugs and make sure that none of the porcelain is cracked. Usually, ignition problems only show themselves under a load.
Eddie
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Well then it sounds like it is time for a cyl leak down and compression test. May be a valve some place. But first have you done any tune ups lately ?
Last edited by Boat Tech; 04-18-2009 at 10:23 PM.