Replace the ignition module in the distributor if it is not yet the 3 wire unit. Look on the back/bottom of the distributor and check to see how many wires come out: white with red stripe, white with green stripe and a black ground means you already have the updated unit. If it does not have the black wire, its the original module and needs to be replaced.
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Fixing everyone elses boat just so I can use mine... -
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I got it fixed. It was the cap and rotor. The sputtering/backfiring issue is still there but I believe it’s the spark plugs. Was able to get one out easy and it was solid blackComment
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Good news: you've got some worn/failed components switched out, and you've got one plug out to verify another component you know needs to be swapped out (the plugs)
Bad news: It's the plugs.Comment
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So I changed the plugs, pretty stuck but none broke! Still have the backfire/popping issue. New spark plug wires? Fuel pressure regulator? Injectors?
where would yall start?Comment
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What did the plugs look like? (all similar, sooty, orange or other colors, etc.)Comment
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All very black and sooty a couple were a little wet but no gunk at all.Comment
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So, definitely running rich, to the point of fuel fouling. Question I should have asked earlier, are you using the boat for surfing, or more general boating activities (tubing, cruising, maybe wakeboarding or skiing)?
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Mainly surfing and cruising. It only does the backfiring and rough running between 2k-3k rpms (perfect surf speed)Comment
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Yeah, that's a high load, fairly low rpm application. boatwakes could give you a more definite answer, but, assuming you replaced the plugs with what your engine calls for, if they might be running one range too cold. Again, I'm just spitballing here, so take it for what its worth. For sure get a 2nd (or 3rd) opinion before you change plug ranges. You might also look into getting a surf prop, but I expect that's pricey.
Oh, and kudos for being careful and not breaking a plug!Comment
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It’s the correct spark plugs and gapped correctly. Valves maybe?Comment
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Nah, if you had a problem with valve timing you'd be having problems everywhere. I believe you that the plugs are correct, for what the boat was designed for. Since the engine doesn't have O2 sensors, it's blind as to seeing if the engine is running rich or lean. Since it's blind, the fuel mapping is built around what the boat was designed for. Wakeboarding at 18-22 mph is its sweet spot, probably turning 3000 rpm (no ballast) at medium throttle. Surfing runs much lower rpm (unless you change the prop), and pretty high throttle settings.
In my opinion, this (low rpm, high throttle settings) is expected to be a launch of the boat out of the hole, and therefore richer with slightly retarded timing (@boatwakes can confirm/deny this). If you stay in this region, I could see the plugs fuel fouling pretty easily.
Again, this is just my opinion. As always, take it with a grain of salt.
HTH, and have a good one,
MikeComment
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Sorry but that just confused me a little bit haha. Are you saying just check the timing?Comment
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If I'm correct, then No. The base timing is around 8-10 degrees, but setting it requires a good timing light, disabling the fuel system (you don't want the engine to start), a friend to twist the key, and something to record the timing flash so you can read the mark (phew, and ugh). We got it done when replacing the long block, but it was tedious.
It's easier (IMO) to just read what the engine is doing. If the engine starts fine, and runs under cruise conditions well (say 3600 rpm and 30 mph, no ballast), then the timing is in the ballpark. To dial it in more than that you need a scan tool, and those are expensive, not that user-friendly, and require an annual subscription (In other words, not for the DIYer).
What I was referring to was the fuel and timing mapping in the ECM.Comment
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Gotcha. I can take that off and get it tested at an autozone or something correct?Comment
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