Ticking noise on 454 mag

tcgravy

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May 18, 2008
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76
1989 Mercruiser 454 magnum (rectangular port heads)
all stock, quadrajet carb, aluminum high-rise intake
Pushes a 1989 baja sunsport 210 (21') with a 25p turbo prop

Recently changed intake manifold gaskets due to small leak. Took it out to lake for first time and it ran flawlessly, intake leak definitely fixed and engine running great.

Then about 5 hours into the day (probably 1.5 hours of run time on boat) while trying to pull tubers I got a loud clatter on takeoff. Idled home after that with a tick the whole way. It ticks at idle and gets worse as rpms go up. Here is a video so you can hear the ticking noise.
http://www.youtube.com/watch?v=ffCCQn2uoRg

Anyways, I also found that the #8 spark plug is black as can be (dry, carbon black, not oily). All other plugs on that side are a decent tan color (about what they should be at idle). FYI, the oil level is fine (not losing any, not low) and the engine temp is in normal operating range, nothing close to overheating all day (highest temp probably 170 degrees).


Am I looking at trouble with a valve??
 

Josh P

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Aug 26, 2009
Messages
328
Re: Ticking noise on 454 mag

sounds like rocker arm or lifter chatter from loose valves. pull valve covers and check valve lash would be the place to start
 

OldNBold51

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Apr 19, 2010
Messages
169
Re: Ticking noise on 454 mag

sounds like rocker arm or lifter chatter from loose valves. pull valve covers and check valve lash would be the place to start

that's what it sounds like to me as well.
 

mjfink

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Sep 9, 2011
Messages
136
Re: Ticking noise on 454 mag

I had a similar noise in my engine which turned out to be a valve that had been knocked off the pushrod. The root cause was water ingestion (water kept the valve from opening) from a bad exhaust.

1989 Mercruiser 454 magnum (rectangular port heads)
all stock, quadrajet carb, aluminum high-rise intake
Pushes a 1989 baja sunsport 210 (21') with a 25p turbo prop

Recently changed intake manifold gaskets due to small leak. Took it out to lake for first time and it ran flawlessly, intake leak definitely fixed and engine running great.

Then about 5 hours into the day (probably 1.5 hours of run time on boat) while trying to pull tubers I got a loud clatter on takeoff. Idled home after that with a tick the whole way. It ticks at idle and gets worse as rpms go up. Here is a video so you can hear the ticking noise.
http://www.youtube.com/watch?v=ffCCQn2uoRg

Anyways, I also found that the #8 spark plug is black as can be (dry, carbon black, not oily). All other plugs on that side are a decent tan color (about what they should be at idle). FYI, the oil level is fine (not losing any, not low) and the engine temp is in normal operating range, nothing close to overheating all day (highest temp probably 170 degrees).


Am I looking at trouble with a valve??
 

Speakrdude

Ensign
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Feb 25, 2004
Messages
942
Re: Ticking noise on 454 mag

And from listening to your video, It's #5 or #7 rocker arms.
 

tpenfield

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17,620
Re: Ticking noise on 454 mag

Nice sewing machine you got there . . . needs a valve adjustment . . . check to see if the lifter(s) on the port side are OK.
 

Jlawsen

Master Chief Petty Officer
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Apr 22, 2012
Messages
810
Re: Ticking noise on 454 mag

Pull the dipstick out about 1" and check the engine again. Trust me, do this now or you'll be really mad if you find out that's all it was after you've pulled the heads. If that's not it then pull the valve covers and start inspecting. If it's a lifter that's failed it'll be a little harder to find but it could just be that you dropped a piece of old gasket in the valley and it's stuck under the push rod so the lifter can't pump up. Don't even ask me how I know that can happen:facepalm:
 

ydnar44

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Jun 21, 2011
Messages
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Re: Ticking noise on 454 mag

How did you fix the hesitation backfire issue, i had the same problem, it was an overheated ignition coil, when puttin around for long periods of time would have that problem when trying to plane out. I always keep the bilge blower on now. Have not had any problems
 

04fxdwgi

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Jun 10, 2011
Messages
754
Re: Ticking noise on 454 mag

What's the oil pressure, what weight oil are you running and how long since it's been changed?
 

ENSIGN

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1,179
Re: Ticking noise on 454 mag

With the engine warmed up check the oil pressure with a mechanical gauge.
 

tcgravy

Petty Officer 3rd Class
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May 18, 2008
Messages
76
Re: Ticking noise on 454 mag

UPDATE FROM ORIGINAL POSTER: Finally getting back to this thread

Ended up getting the valve cover off and checking valve lash on all cylinders on the starboard side (#2, #4, #6, #8). Found 3 valves with loose rocker nuts (more than a few turns, lots and lots of play:
- cylinder #8 exhaust valve
- cylinder #4 exhaust valve
- cylinder #4 intake valve
I adjusted lash on here (going 1/2 turn past zero lash)...I have adjusted valve lash multiple times before and was using merc manual to guide me as well. With there being 3 loose valves, I also checked all other valves on that side. All others seemed to be just fine and within spec.

So, I thought I had this problem fixed, but did NOT. Went to start the boat...would not start after lots of cranking. Eventually fired but sounded terrible and then stalled. Then tried to start it one more time and now engine won't turn over. Also there is excess gas that appears to have overflowed out of the carburetor. I got nothin....obviously something went TERRIBLY WRONG HERE. Just hoping whatever I broke is still fixable.

PLEASE HELP / OFFER ADVICE
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: Ticking noise on 454 mag

you may have had collapsed lifters and now the valves are hung open since you adjusted them. I would have adjusted them running, however that is me.
 

tcgravy

Petty Officer 3rd Class
Joined
May 18, 2008
Messages
76
Re: Ticking noise on 454 mag

you may have had collapsed lifters and now the valves are hung open since you adjusted them. I would have adjusted them running, however that is me.

Whats the best way to check for collapsed lifters? And how does that lend towards an engine that won't turn over? Please let me know.

As for adjusting valves while running, i would have but in order to take the valve cover off on a 454 mag you have to remove the exhaust manifold, and didnt really wanna run it w/ no exhaust manifold.
 

tcgravy

Petty Officer 3rd Class
Joined
May 18, 2008
Messages
76
Re: Ticking noise on 454 mag

UPDATE FROM ORIGINAL POSTER: Finally getting back to this thread

Ended up getting the valve cover off and checking valve lash on all cylinders on the starboard side (#2, #4, #6, #8). Found 3 valves with loose rocker nuts (more than a few turns, lots and lots of play:
- cylinder #8 exhaust valve
- cylinder #4 exhaust valve
- cylinder #4 intake valve
I adjusted lash on here (going 1/2 turn past zero lash)...I have adjusted valve lash multiple times before and was using merc manual to guide me as well. With there being 3 loose valves, I also checked all other valves on that side. All others seemed to be just fine and within spec.

So, I thought I had this problem fixed, but did NOT. Went to start the boat...would not start after lots of cranking. Eventually fired but sounded terrible and then stalled. Then tried to start it one more time and now engine won't turn over. Also there is excess gas that appears to have overflowed out of the carburetor. I got nothin....obviously something went TERRIBLY WRONG HERE. Just hoping whatever I broke is still fixable.

PLEASE HELP / OFFER ADVICE


OK YET ANOTHER UPDATE.....

Turns out the reason the engine won't turn over is because....its full of gas. Looks like my needle & seat in the carb isn't doing its job and gas is just going everywhere. Pulled all the spark plugs and engine turns over fine. So thats a separate problem to fix it would appear.

BUT.....

it does have me second guessing my valve/rocker nut adjustment though, not sure if I need to be investigating lifters or not? As always, any input is appreciated.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: Ticking noise on 454 mag

you have a few problems now.

first, fix the carb. if the carb was dumping that much fuel, it most likely thinned the oil severely when running.

next, change the oil - its now full of fuel

Third, you will need to back off each rocker and start from zero.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: Ticking noise on 454 mag

there probably was very little to no oil pressure because the oil was most likely thinned out by fuel.
 

tcgravy

Petty Officer 3rd Class
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Messages
76
Re: Ticking noise on 454 mag

you have a few problems now.

first, fix the carb. if the carb was dumping that much fuel, it most likely thinned the oil severely when running.

next, change the oil - its now full of fuel

Third, you will need to back off each rocker and start from zero.



Changed the oil, oil pressure is fine (about 35 psi at idle)

Thought I fixed the carb.....disassembled air horn, took everything apart, put in new needle and seat, tested needle and seat by holding it down w/my finger and turning on my electric fuel pump, it worked, so thought I was good.put it all back together, bowl still overflowing........

Disassembled carb again, am finding that the needle and seat works when I hold it down with my finger, but the float is not capable of holding down the needle properly. Have tried install w/ and without the little clip, doesn't seem to matter. Float definitely works/functions. C-shaped clip that acts as the fulcrum lever is installed correctly. Kind of want to gouge my eyes out right now.

Ideas?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: Ticking noise on 454 mag

what is your fuel pressure?

carbs have issues over 4psi
 

OldNBold51

Petty Officer 2nd Class
Joined
Apr 19, 2010
Messages
169
Re: Ticking noise on 454 mag

You need to rule out gasoline (ethanol) as a culprit. I rebuilt my carb 3 times thinking my float wasn't stopping flow based on ALL the gas in my intake. I had a pool of gas in the intake. I had fire, compression and what i thought was way too much fuel as there was a puddle forming in the intake when i was trying to crank and fire. I'd even get a little fire when I shot starter fluid down the carb. I had 16 gallons of new gas on top of what was left over from previous season. That gas, maybe 8-10 gals was only 5 months old and had stabil in it.

So, to rule out gas as culprit, I made a 1 gallon auxillary tank and hung it up over the motor like an IV, plumbed it into the fuel/water separator and within a few cranks she started right up, idled fine and i ran the whole 1/2 gallon out.

The hard part was disposing all the gas in the boat tank!

The thing i did to make sure the gas was out of the intake was take the carb off, which was now about a 3 minute job due to my previous carb rebuilding, take the plugs out and spin the engine to clear the intake of fuel and then I used a leaf blower and blew down the intake tract for several minutes, thus really drying out the intake. I also emptied the carb of fuel. Once I plumbed the auxillary tank, it started once fuel was into the carb.
 
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