Hello

My Mercury 500 EFI engine has 50 hours since it was rebuilt at an authorized workshop in Sweden

Now it makes a noise, small video !!!

https://dai.ly/k2dvC9KQhqKhIhCgHSA

What investigations do you recommend ??

If I had to remplace the hydraulic liftyers, the originals ( 849947T01 ) cost a fortune !!

Is there another good alternative ?

Thanks in advance for your help

Bajalux / Europe

To me, it definitely sounds like a lifter/rocker arm tapping. What all was done during the 'rebuild'?

Who adjusted the pre load on the rockers?

Get your self a new shop, obviously they dont know how to adjust the valves lash

Hello

Thanks you for your initial comments

Finding a good marine mechanic is not easy in Europe without driving 1000 miles on way !!!

In my location, I search a mechanic Corvette or Mustang for help ..
I have workshop manual n° 6 if needed

Thanks
Bajalux

Trevor Fowler from MidMo Marine Services posted this video a few years ago. It seems to work pretty well.

My audio sucks, but if it makes a noise like you guys say and engine was fine for 50hrs, a valve train piece coukd be broke or worn. Lifter, valvespring, rocker, stuck valve that bent s pushrod, or etc

Aside from the noise, is it down on power? Maybe it's just my workstation, but I'm hearing an exhaust leak.

I hear multiple rocker arms chattering........I lash valves in the firing order 1/4 turn of the crank puts that next cylinder on the base circle of the cam.....not like that video.1/2 turn down is pretty standard unless you're running Morels.....lol

If it was fine for the first 50 hours then it suddenly started making the noise then I doubt if it is the valve adjustment. Either a lifter has stuck or failed or something else has broken or come loose. Before you touch anything you need to call the shop that rebuilt the engine. Especially if there was a warranty. As soon as you touch it the warranty might be void. Call them and do what they say first.

I have heard exhaust manifold gaskets sound very similar and have fooled quite a few guys.