Merc 7.4 Gen V clicking noise
 

Hi,

I've got a 454 that performs well, no power loss with throttle at all. However; I have clicking noise that is noticeable around 2500 rpm and gets louder as you increase rpm.

Jt

Does it sound like it is from the engine area or further back? Is it more pronounced when turning the wheel in either direction? Possibly suspect a u-joint.

Sounds like engine, I had the u joint inspected before install this spring.

I have had blown exhaust gaskets and cracked plugs that leak around the shell make funny noises. Is there a way to run this while you listen around and try to pin point area of noise either front to back or port to strb?

Just had a lifter explode in my HP500. Does it sound like a lifter ticking?

Likely, or a loose rocker. Wouldn't a stuck lifter effect valve operation? If it's the exhaust valve would I smell un burnt fuel in the exhaust? ( cause I do)

Any way to unstick without opening up? If this is the case, would it be the cam tapping on the flat tappet?

More than likely, my RM custom cam was destroyed also in the mix of things.

3 years later, motor still ticking above 2500 rpm. Motor runs great, acceleration and WOT - just ticks. I've put in additives with every oil change, and changed from merc 25-40 to 15-40. The sound actually driving me crazy, but it's hard to invest in a rebuild or opening it up when the engine fires up first crank, and smooth operation. It does smoke a bit on start up, but I'm running a bravo 3 and I've read it needs to run rich at idle to shift.

Any thoughts?

Thanks,

[QUOTE=hyperlite98;4557564]3 years later, motor still ticking above 2500 rpm. Motor runs great, acceleration and WOT

I'M NOT A MECHANIC

Did you check the exhaust flappers - that ones that are in or right before the Y pipe? I have been told that they will rust out or get loose and start flipping and flopping. I agree if everything else is running well don't mess with it.

3pointstar

The flapper are loudest at idle. The reversion pulses pulling them shut causes the noise. Once you are on the throttle, they are pinned open and shut up. Ok, I figured thread out. Hyperlite is 77 nova. Screen name change.