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Hey everyone. Thank you in advance for help on this. Your website has helped me tremendously getting the gremlins out of this new to me boat. (Bad kill switch and the one-way diodes #1n4003 on the purple wire in the harness. Both intermittent problems cutting power off to the engine.
Boat runs great but has a knocking/pinging noise that I'd like to get figured out.
1998 Nautique Super Sport V-drive with 5.8L Pro-boss multi-port efi gt-40 (600 hours).
At startup every time the motor sounds great but after a few moments as the motor settles down to idle it develops a knocking noise. This knocking/pinging noise will speed up consistently with engine speed. The motor still has plenty of power and performs very well but always has this knocking noise except for several seconds after starting the engine.
Could this just be spark knock from a bad knock sensor?
Or something up with the timing?
Just very weird that it doesn't knock at all (hot or cold) every start up until what I'm thinking is the choke and timing goes from start mode to engine idle settings? If something more major was wrong wouldn't it knock no matter what?
I ran the boat all last summer like this. It does burn/use a little oil.
I tried:
Pulling each spark plug wire off 1 at a time - no noise change
Compression test -2 cylinders a little low 130psi the rest 145psi
Removed exhaust manifolds and found 2 scuffed cylinders.
With stethoscope the sound sounds worse on the valve cover on port side of the boat. I took it off and checked the lifters and replaced a couple push rods. - no change.
I will try to get a video or sound recording of the noise.
Just wishful thinking here that it is just a bad knock sensor, hall sensor, or something, but am sick of throwing parts at it if it is a deeper problem. Summer is too short in Michigan so I may press our luck again and see if she holds together if I need an engine rebuild. Now is not the time for that.
Other new parts.
Sparkplugs, wires, cap and rotor
Both the relays (ecm and fuel pump) multiple, multiple times (stupid me and the #1n4003 diode)
New starter and seperate slave solenoid
New PCV
Boat runs great but has a knocking/pinging noise that I'd like to get figured out.
1998 Nautique Super Sport V-drive with 5.8L Pro-boss multi-port efi gt-40 (600 hours).
At startup every time the motor sounds great but after a few moments as the motor settles down to idle it develops a knocking noise. This knocking/pinging noise will speed up consistently with engine speed. The motor still has plenty of power and performs very well but always has this knocking noise except for several seconds after starting the engine.
Could this just be spark knock from a bad knock sensor?
Or something up with the timing?
Just very weird that it doesn't knock at all (hot or cold) every start up until what I'm thinking is the choke and timing goes from start mode to engine idle settings? If something more major was wrong wouldn't it knock no matter what?
I ran the boat all last summer like this. It does burn/use a little oil.
I tried:
Pulling each spark plug wire off 1 at a time - no noise change
Compression test -2 cylinders a little low 130psi the rest 145psi
Removed exhaust manifolds and found 2 scuffed cylinders.
With stethoscope the sound sounds worse on the valve cover on port side of the boat. I took it off and checked the lifters and replaced a couple push rods. - no change.
I will try to get a video or sound recording of the noise.
Just wishful thinking here that it is just a bad knock sensor, hall sensor, or something, but am sick of throwing parts at it if it is a deeper problem. Summer is too short in Michigan so I may press our luck again and see if she holds together if I need an engine rebuild. Now is not the time for that.
Other new parts.
Sparkplugs, wires, cap and rotor
Both the relays (ecm and fuel pump) multiple, multiple times (stupid me and the #1n4003 diode)
New starter and seperate slave solenoid
New PCV