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525 running rough, back fire?

Old 04-14-2021, 07:24 AM
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Default 525 running rough, back fire?

525 issue. Boat was not used for a year or so. Starboard didn't start, turns out a simple slave solenoid. Replaced, started right up. I took out all the plugs, lubed the cylinders, etc. sounds good in idle. Took it for a test ride. Around 1800-2000 rpm, sounds rough, like dieseling sort of. (I think that's what called, when it sounds like wroom wroom wroom, instead of nice even wrooooooooom sound) Plus randomly makes a loud snap, clink sound. I think it's backfiring. Didn't go past 2500, the higher the RPM's the worse it sounds. Idle seems ok. Suggestions? What should I look for or test.?
THX
P
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Old 04-14-2021, 07:26 AM
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Check fuel pressure on the rails with guage...we had a similar issue and it was the fuel pressure regulator.

also check cap and spark wires...
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Old 04-14-2021, 08:39 AM
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put fresh fuel in it
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Old 04-14-2021, 08:50 AM
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If you have a rinda, I’d also do a cylinder cut out test. I had one acting up last year and swapped out one banks coil pack to cure it. Did the other side as preventative measure.
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Old 04-14-2021, 08:53 AM
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Also, the PCM 555 controller is voltage sensitive so going over connections and hounds might be worthwhile. Ask me how I know...
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Old 04-14-2021, 08:55 AM
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Originally Posted by endeavor1 View Post
If you have a rinda, I’d also do a cylinder cut out test. I had one acting up last year and swapped out one banks coil pack to cure it. Did the other side as preventative measure.
What's a "rinda".. I'm bad, but ?
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Old 04-14-2021, 09:03 AM
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Rinda is a scantool

X 2 : check fuel psi

you could have fouled a plug or 2 or 8 :wink when you sprayed ‘lube’ in the cylinders. Replace plugs and make sure their connectors click on.

Start there.

Last edited by SB; 04-14-2021 at 09:06 AM.
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Old 04-14-2021, 09:28 AM
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I don't have the scanning tool, but I have the Smartcraft screen. There are some codes I will have to track down what they are. I turned over the motor before I put the plugs back, pushing anything out, so I doubt the plugs are bad. Gaps were good and I cleaned them, but I will check them further. Fuel pressure regulator makes sense. Or even one of the fuel pumps.
THX
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Old 04-22-2021, 09:35 AM
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Well, update: And I need some help.
I hoped I just swapped a plug wire, but no. Wires are all on the right plugs, so it has to be the fuel pressure regulator. It's under the block, near the electric fuel pump, but I can't even see it. How on earth do I get to it and change it.???
Any suggestions? THX
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Old 04-22-2021, 10:15 AM
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So, you checked the psi ? What was it ?

What where the codes you got on the Smartcraft ?
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