TAP TAP TAP

Lawman · Post by **Lawman** » Sat Sep 24, 2011 2:40 pm

Hey Guys, I have had a metallic tapping coming from my port side LM318. I thought it was lifter noise but have narrowed it down to the very front of the motor. I'm thinkin' timing chain ?? I have'nt moved the crank and looked at the rotor for play yet, but if it's a chain is it a very big job? The only other thing I can think of is it might be the fuel pump arm ????? Any advise would be appreciated.

myakka · Post by **myakka** » Sat Sep 24, 2011 5:47 pm

That sound on mine ended up being the water pump.I hope you get off as easy as I did.
Mike

Lawman · Post by **Lawman** » Sun Sep 25, 2011 2:43 pm

I never knew a water pump could make a tapping sound, it comes and goes usually around 1500rpms is the loudest and still taps like a lifter at idle,but is gone around 2000rpms???? Boats, you gotta luvem'

vabeach1234 · Post by **vabeach1234** » Sun Sep 25, 2011 8:59 pm

I had a rattle from the water pump as well on my 318. See post below.

http://www.trojanboats.net/wforum/viewt ... highlight=

Also, I constantly have to spray my belts with belt conditioner. They always make a racket when the boat has sat for longer than a week.

Big D · Post by **Big D** » Thu Sep 29, 2011 8:46 pm

Could be fuel pump, circ pump. Also check alt and raw water pump. Timing chain not too hard if you know what to do. Need some room under oil pan to drop the front a bit. Sure it's coming from the front? Acoustics in an engine compartment can play games with you sometimes.

Lawman · Post by **Lawman** » Fri Sep 30, 2011 7:59 am

It's definately from the front of motor, I'm gonna get my stethascope out to try and pin point it, just wondering if anyone had this type of senario before. Thank you for all the advise guys.

Stripermann2 · Post by **Stripermann2** » Fri Sep 30, 2011 8:52 am

Lawman, is it possible it's an exhaust leak making the noise you're hearing?
I've had a blown out gasket a few times making a tapping sound.
Just a thought...keep us posted.

Mike Kulp · Post by **Mike Kulp** » Fri Sep 30, 2011 12:42 pm

Possibly fuel pump, If I remember correctly chryslers are driven of eccentric cam bolted to the upper timing gear. We have seen this in automotive engines. on small block chevy's we use to unbolt them and pack the cavity in the fuel pump with grease to verify the noise would go away. Then replace the pump.

Lawman · Post by **Lawman** » Tue Oct 04, 2011 8:43 pm

You were right guy's, the tapping was the fuel pump, very loose arm, but I'm also getting lifter noise from the right bank (left is quiet) it's more like a clacking from down in the head so looks like it's time to do lifters. I'm hoping to get them out without removing the intake. Anyone done this before??

Lawman · Post by **Lawman** » Tue Oct 04, 2011 10:41 pm

Also. could this be a loose rocker arm assembly where it's only on one side ? It does sound like it's coming from all the lifters ????????