Mercruiser 4.3 1998. Ticking

[asco]

Hi there. I have a strange ticking comming for my engine. I can’t seem to find where it’s coming from. The noise starts when it get warm. Running like 2500 rpm for 10-15 minutes. When I slow it down to idle, the sound is still there. The noise is not there when it’s could. If I keep running at idle, it stops again after 10-16 minutes.

I notice that one of the manifolds is more
warm, then they other one. But the temperature ain’t showIng it’s to warm.

I had the boat for a month now, and in the beginning, there was no problem.

any help is more then welcome

https://youtu.be/di8VYSAGgi0

 

[tank1949]

Former owners always patch them up as best as to sell them. Sorry... Is boat salt water used? Maybe time to replace manifolds and risers? I assume V8? Possibly rusted up riser if more than 4 seasons in salt water. I use an infered thermometer. It is amazing to identify hot spots. If not, add a can of Marvel Mystery oil. It is a marvel! Maybe also exhaust leak. I have one on a 1995 Chevy truck that only is noticeable after it gets hot. Go to Harbor Freight and buy a stethoscope to listen better. Good luck!

 

[H20Rat]

Take off the belts and see if the ticking is still there. Failing bearings/idlers can sound exactly like an exhaust leak.

Looking at your video, there shouldn't be that much steam/smoke coming from the breather tubes. Shouldn't ever really be visible at all. That is a sign of a not-so-happy engine.

 

[Scott Danforth]

one manifold will always be warmer than the other

sounds like you have a dead cylinder. could be a bad plug, a bad wire, or something else.

 

[tpenfield]

:welcome: to iBoats . . .

My first thought was that there is a bomb in your engine counting down until it goes off.

More likely, how about a bum valve lifter. Use a mechanics stethoscope to further isolate the noise.

 

[Rick Stephens]

If I didn't have a stethoscope, I'd use a simple wood dowel. Lifter or exhaust shutter be my bet.

 

[achris]

Couple of things. Firstly, batwing manifolds. Merc stopped producing those in the late 90s. That makes them AT LEAST 20 years old. Well passed time to replace them.

That ticking is a cylinder not firing. I suspect once you pull the manifolds you'll see which cylinder the water is leaking into...

Chris........

 

[asco]

Take off the belts and see if the ticking is still there. Failing bearings/idlers can sound exactly like an exhaust leak.

Looking at your video, there shouldn't be that much steam/smoke coming from the breather tubes. Shouldn't ever really be visible at all. That is a sign of a not-so-happy engine.

Well i notice the smoke to. I just thought i was because, the gasolin was cold and the engine warm. What is it an indikator for? to hot engine?

i will try the bealt thing .

can it be that its something in the waterpump/cooling sytem, that makes it goes to warm? like seeweed or something?

 

[asco]

Couple of things. Firstly, batwing manifolds. Merc stopped producing those in the late 90s. That makes them AT LEAST 20 years old. Well passed time to replace them.

That ticking is a cylinder not firing. I suspect once you pull the manifolds you'll see which cylinder the water is leaking into...

Chris........

i just changes plugs on it. two of the cylinder had black plugs. But it was becaurse of an bad power cap end rotator.

oh no, they are quit expensive .... the job dont look som complicated? DIY?
if one of the cylinder did not fire, then i would have a really rough engine, and i dont...?

 

[asco]

:welcome: to iBoats . . .

My first thought was that there is a bomb in your engine counting down until it goes off.

More likely, how about a bum valve lifter. Use a mechanics stethoscope to further isolate the noise.

that was my boat mechanics thought too. be looking at the video only.

 

[asco]

one manifold will always be warmer than the other

sounds like you have a dead cylinder. could be a bad plug, a bad wire, or something else.

okey.. but when is it critical?

 

[Scott Danforth]

okey.. but when is it critical?

now its critical. find out what went wrong and fix it before it becomes catestrophic

 

[H20Rat]

if one of the cylinder did not fire, then i would have a really rough engine, and i dont...?

You would be surprised... Engines can run quite well down a cylinder. (at least until the root cause of why that cylinder is down takes out the rest of the engine)

 

[H20Rat]

Well i notice the smoke to. I just thought i was because, the gasolin was cold and the engine warm. What is it an indikator for? to hot engine?

i will try the bealt thing .

can it be that its something in the waterpump/cooling sytem, that makes it goes to warm? like seeweed or something?

The smoke/vapor is from the crankcase. It could be a couple different things... Gasoline if you have zero compression in a cylinder, water if you are getting water in the crankcase, possibly oil if you have cylinder with a bunch of blowby. Smelling the vapor will help some. From the looks, it isn't oil, most likely water but possibly gas.

In any case, I've owned quite a few 4.3's, never once have I seen visible smoke from the breathers like that.

 

[Scott Danforth]

if one of the cylinder did not fire, then i would have a really rough engine, and i dont...?

I have a friend of mine with a carb'd 4.3 in his boat.

2 years ago, the boat flat quite running right, was down on power. he took it to the marina, where two "pros" took the boat, tried different props, etc and couldnt figure it out.

I asked him to do a drop test (pull plug wires until you find a cylinder that doesnt change engine RPM.) I also asked if he checked his y-pipe for critters

the issues he had, one plug was bad, the motor was running on 5 cylinders, and one of his shutters dropped and was plugging the exhaust.

the motor still ran silky smooth with only running on 5 cylinders

so, unless you do a drop test along with a compression test, do not assume you are running on all cylinders. most V6's and V8's wont run rough.

 

[asco]

The smoke/vapor is from the crankcase. It could be a couple different things... Gasoline if you have zero compression in a cylinder, water if you are getting water in the crankcase, possibly oil if you have cylinder with a bunch of blowby. Smelling the vapor will help some. From the looks, it isn't oil, most likely water but possibly gas.

In any case, I've owned quite a few 4.3's, never once have I seen visible smoke from the breathers like that.

Thx for your respons. Well as you know i have en issue, that the engine starts to tick alot when it gets warm. My mekaniks says its a value lifter, that is defect. maybe that will send exhaust gas in to the crankcase? if it has a hard time closing?

anyway im pulling the crankcase off, to change the value lifter. here i can see if there is water in the oile, right...?
There is no white olie on the dipstick!

i thing i will do a compression test to, just to make sure! but i know the engine has a low hours!

 

[asco]

I have a friend of mine with a carb'd 4.3 in his boat.

2 years ago, the boat flat quite running right, was down on power. he took it to the marina, where two "pros" took the boat, tried different props, etc and couldnt figure it out.

I asked him to do a drop test (pull plug wires until you find a cylinder that doesnt change engine RPM.) I also asked if he checked his y-pipe for critters

the issues he had, one plug was bad, the motor was running on 5 cylinders, and one of his shutters dropped and was plugging the exhaust.

the motor still ran silky smooth with only running on 5 cylinders

so, unless you do a drop test along with a compression test, do not assume you are running on all cylinders. most V6's and V8's wont run rough.

thx alot!!! i recently have a RPM surgin issue. that is fix'ed now. it was my power distributor cap. so i just 1 week ago changed powerplugs, cap, rotor arm and wires. That helped ALOT!
but i didten do a drop test.
i will try the drop test (pulling plug wires, and see if one of them do'sent change the RPM), but if all of the changes the RPM, then i know its running on all cylinder, right?

i will do a compression test to.

when you say shutters, do you mean the flap there is opening/closing exhaust and water?
And the Y-pipe what is that? exhaust?

 

[Colliemcc]

thx alot!!! i recently have a RPM surgin issue. that is fix'ed now. it was my power distributor cap. so i just 1 week ago changed powerplugs, cap, rotor arm and wires. That helped ALOT!
but i didten do a drop test.
i will try the drop test (pulling plug wires, and see if one of them do'sent change the RPM), but if all of the changes the RPM, then i know its running on all cylinder, right?

i will do a compression test to.

when you say shutters, do you mean the flap there is opening/closing exhaust and water?
And the Y-pipe what is that? exhaust?

How did you fair out with this?