sandkicker
Outstanding Contributor
While readjusting the idle mixture after changing a bad disti cap and preemptively replacing an 11 season old sensor in the disti, I noticed a definitive tap from port side of engine. This engine has a TKS 2bbl carb (which works correctly) and as a result I don't usually have my head in the engine box @ idle and with thru transom exhaust I've never noticed it before so I don't know how long I've had this noise.
Engine... 5.7L MIE S/N 0w395664 ( circa 2006) FWC about 400 hrs.
Oil and filter replaced annually, using recommended 25w40 quicksilver oil. Engine never revved over 4600 RPM.
So far, I've:
1) Flushed engine with motor medic and then with 0w20 and then changed oil and filter.
2) removed serpentine belt to check if accessories are noisy
3) turned drive port to stb to see if noise changes
5) using a screwdriver as a listening stick, STBD has a nice buzz to it, while PORT has a definite louder tap.
I've been elbows deep in engines before, but never a hydraulic liftered (roller) engine.
My next step is to pull the rocker cover but I have center rise manifolds and at a minimum will have to back off the manifold attachment bolts somewhat to get the rocker cover off.
Per my research...I'm think I'm looking at ( in no particular order)
1) Collapsed lifter
2) Bent push rod
3) loose nut on rocker adjuster causing lash adjustment to be off
4) Pressed in stud that the rocker adjuster is on is backing out of head.
5) stuck valve?
I know how to check for #4 above ( a straight edge) and #5 and #2 as well, but how do I differentiate between a collapsed/sticky lifter and a backed off adjuster nut? ( besides readjusting it and seeing if noise comes back????)
As I said above, hydraulic lifters are new ground for me. Any help would be appreciated. It's getting VERY late in the season here in NJ and I'd like to get this fixed before I pull the boat and hopefully get another fishing trip in before my last trip to the haul out point. Water will be shut off soon at my winter store yard so if not fixed soon, will have to wait until next spring to fix.
One more thing... couple of times when I restarted the engine, there was a slight backfire pop I never notice before.
Engine... 5.7L MIE S/N 0w395664 ( circa 2006) FWC about 400 hrs.
Oil and filter replaced annually, using recommended 25w40 quicksilver oil. Engine never revved over 4600 RPM.
So far, I've:
1) Flushed engine with motor medic and then with 0w20 and then changed oil and filter.
2) removed serpentine belt to check if accessories are noisy
3) turned drive port to stb to see if noise changes
5) using a screwdriver as a listening stick, STBD has a nice buzz to it, while PORT has a definite louder tap.
I've been elbows deep in engines before, but never a hydraulic liftered (roller) engine.
My next step is to pull the rocker cover but I have center rise manifolds and at a minimum will have to back off the manifold attachment bolts somewhat to get the rocker cover off.
Per my research...I'm think I'm looking at ( in no particular order)
1) Collapsed lifter
2) Bent push rod
3) loose nut on rocker adjuster causing lash adjustment to be off
4) Pressed in stud that the rocker adjuster is on is backing out of head.
5) stuck valve?
I know how to check for #4 above ( a straight edge) and #5 and #2 as well, but how do I differentiate between a collapsed/sticky lifter and a backed off adjuster nut? ( besides readjusting it and seeing if noise comes back????)
As I said above, hydraulic lifters are new ground for me. Any help would be appreciated. It's getting VERY late in the season here in NJ and I'd like to get this fixed before I pull the boat and hopefully get another fishing trip in before my last trip to the haul out point. Water will be shut off soon at my winter store yard so if not fixed soon, will have to wait until next spring to fix.
One more thing... couple of times when I restarted the engine, there was a slight backfire pop I never notice before.
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