Lower end knock...

[Druff1]

I'm hearing a ticking or kind of a knocking from the front lower crank area. Sounds like its down by the fuel pump. I put a pipe on the fuel pump, and timing chain cover. Sounds like it coming from the timing chain cover. Knocks from 600rpm to around 900 rpm, then quits till about 1400 rpm.

This is a new 4.3 long block with less that 2 hours on it. Any ideas?

 

[deadstick]

Re: Lower end knock...

it may have been built with wrong size rod bearings. i have seen this happen before.

 

[searay3]

Re: Lower end knock...

What engine and drive package? If merc, to be certain it is the engine, pull the drive and fired it up for a couple of seconds. See of the noise goes away. Check the oil level. If it still is the engine, go back to whoever rebuilt it. With two hours on a rebuild I would go to them for answers. The liability needs to be with them. If you make any decisions on your own, you may risk the warranty.

 

[KJSmitty]

Re: Lower end knock...

Does it have a mechanical fuel pump? I'm no expert on the 4.3 but have seen/heard many fuel pumps tick/knock as well.

Good luck

 

[Bronc Rider]

Re: Lower end knock...

Does it have a mechanical fuel pump? I'm no expert on the 4.3 but have seen/heard many fuel pumps tick/knock as well.

Good luck

I agree with this. The little rod used to drive the pump will make noise when it gets old. This is only true if its a mechanical pump.

 

[Druff1]

Re: Lower end knock...

I was actually thinking the same thing about the fuel pump.... It is a mechanical one. I took the boat out yesterday (second run on it) and the knock is gone.