540 BBC running poorly
10-22-2018 | 01:58 PM
#31
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Joined: Oct 2017
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From: Merritt Island, FL
Ground straps and all connections and including main Mercury plug all good. As mentioned possible cracked plugs. Fire it up in the dark and check for any arcing etc. just a thought. I've identified some electrical issues in the dark. I have a new DUI with plug wires if your interested in purchasing or just to try. Just pay shipping. Process of elimination. New plugs and believe it or not it wouldn't be the first time even fuel at the pump can be contaminated with water. Happened up north here and cost the station a brand new Diesel engine.
10-22-2018 | 06:42 PM
#32
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From: NW Michigan
Maybe try some brake cleaner and some electrical grease. Might be a long shot but worthy. These kind of issues can drive you nuts. Many of us been there and in some cases it's the simple things we over look. Let me know if you'd like to throw the flame thrower in I have. I'd be happy to ship out for you to try.
10-22-2018 | 06:54 PM
#33
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From: Collierville, TN and Pickwick Lake
I go with contact cleaner instead of brake cleaner.
Brake cleaner is most likely gonna wreak havoc with the rubber/plastic materials of the plug.
It is also very flammable if you decide to use getrdunns flame thrower. 😂
Brake cleaner is most likely gonna wreak havoc with the rubber/plastic materials of the plug.
It is also very flammable if you decide to use getrdunns flame thrower. 😂
Last edited by payuppsucker; 10-22-2018 at 06:58 PM.
10-22-2018 | 07:48 PM
#34
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From: On A Dirt Floor
I use battery cleaner, then blow out. Awesome for trailer plugs too...just sayin. Do decent of snowmobile trailing and those plugs get nasty.
Then my carburetor files for the female part. Male parts usually okay,but if not some emery cloth or fine grit sand paper small strips and use like polishing a crank. Slightly split male prongs. Slightly ! I've pilled some boats harness plugs apart and some people over did it. Doh !
Oh, pet peeve of mine: Do not put Dielectric grease on contact part of electrical plugs. Why do people do this ? Ugggh. It does not pass electricity. uggghh. It helps seals out the elements.
Then my carburetor files for the female part. Male parts usually okay,but if not some emery cloth or fine grit sand paper small strips and use like polishing a crank. Slightly split male prongs. Slightly ! I've pilled some boats harness plugs apart and some people over did it. Doh !Oh, pet peeve of mine: Do not put Dielectric grease on contact part of electrical plugs. Why do people do this ? Ugggh. It does not pass electricity. uggghh. It helps seals out the elements.
Last edited by SB; 10-22-2018 at 07:51 PM.
10-22-2018 | 08:30 PM
#35
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Joined: Aug 2012
Posts: 2,301
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From: Collierville, TN and Pickwick Lake
I use battery cleaner, then blow out. Awesome for trailer plugs too...just sayin. Do decent of snowmobile trailing and those plugs get nasty.Then my carburetor files for the female part. Male parts usually okay,but if not some emery cloth or fine grit sand paper small strips and use like polishing a crank. Slightly split male prongs. Slightly ! I've pilled some boats harness plugs apart and some people over did it. Doh !
Oh, pet peeve of mine: Do not put Dielectric grease on contact part of electrical plugs. Why do people do this ? Ugggh. It does not pass electricity. uggghh. It helps seals out the elements.
Then my carburetor files for the female part. Male parts usually okay,but if not some emery cloth or fine grit sand paper small strips and use like polishing a crank. Slightly split male prongs. Slightly ! I've pilled some boats harness plugs apart and some people over did it. Doh !Oh, pet peeve of mine: Do not put Dielectric grease on contact part of electrical plugs. Why do people do this ? Ugggh. It does not pass electricity. uggghh. It helps seals out the elements.
10-22-2018 | 08:53 PM
#37
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From: Collierville, TN and Pickwick Lake
I guess about as good as having two bad cannon plugs. 🤷🏼*♂️
10-22-2018 | 09:36 PM
#38
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From: chicago
a local buddy of mine did this. He replaced his caps and rotors on his new to him 572's. Engines idled like crap, down on power, etc. He called me a few times to pick my brain. We talked about carb adjustments, fuel system stuff, etc. Finally one day he calls me and tells me he found the issue. He had two plugs wires swapped on both motors!
10-22-2018 | 09:44 PM
#39
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From: ALTO, MI
When i built my 598 CI for my Daytona - on first fire up it wouldn't idle and ran like crap. Turns out I wired the plugs for normal firing order.
Checked the cam card and it didn't say anything about 47 swap. BUT there was a 47 on it so I did the swap.
Ran great.
Checked the cam card and it didn't say anything about 47 swap. BUT there was a 47 on it so I did the swap.
Ran great.
10-22-2018 | 10:57 PM
#40
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From: SF Bay Area
