Valve Noise - Merc 140 - 3.0 - Please Help

[cbr1574]

No one has been able to figure out motor noise.

I have run out of money.

When Boat is in the water and it hits 2,500rpm to 3,000 rpm the valves go crazy. Engine sounds like an old peculator.

When the boat is out of the water I can wind out (3,700rpm - plus) the engine and no valve noise.

Do I need a valve job?

Please, someone help me I don?t know what more to do.

Thank you, so much


Oil pressure ? Good
Temperature ? 140
Propeller ? 14 x 19 pitch
Engine ? Mercruiser 140
Boat ? Say Ray ? Seville II
Size ? 19 Feet

 

[cr2k]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

Are you sure it's the valves and not knocking from too low octane or too high timing?

Sounds like not valves, they tend to make more noise unloaded.

Back off your timing a few degrees and see if that makes it quiet.

If not try readjusting your valves. 3/4 turn down from 0 lash. One cylinder at a time. Firing order 1-3-4-2

Start at TDC with 1 and go 1/2 turn of the crank to 3 so on, so on.

What viscosity (weight) oil are you running?

 

[Bondo]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

When Boat is in the water and it hits 2,500rpm to 3,000 rpm the valves go crazy. Engine sounds like an old peculator.

Ayuh,... By your discription,...
I'd sooner think you're hearing Detonation, not necessarily the Valve train...

 

[Don S]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

Does this engine have a year, maybe a SN? What ignition system?

 

[180shabah]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

water in fuel, tune up, what's the history?

 

[cbr1574]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

Are you sure it's the valves and not knocking from too low octane or too high timing?

Not 100% Sure - I would say 90% Sure

I have tried octane bust ? Did not Work.

Sounds like not valves, they tend to make more noise unloaded.
That's what I think also. No noise when off the water, in drive way.

Back off your timing a few degrees and see if that makes it quiet.
Don't know how to do this.

If not try readjusting your valves. 3/4 turn down from 0 lash. One cylinder at a time. Firing order 1-3-4-2

Start at TDC with 1 and go 1/2 turn of the crank to 3 so on, so on.
What is TDC?

What viscosity (weight) oil are you running?
Rotella ? 15W/40 ? Recommend for better compression - I live in Hollywood Florida, Hot weather.

Thank you so much.

PS
I been unemployeed for 1.5 year. I'm really broke. so its hard to take to mechanis and just pay him to fix problem.

 

[bigskiohio]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

I have tried octane bust ? Did not Work. higher octane gas



Back off your timing a few degrees and see if that makes it quiet.
Get a mechanical friend to show you. Need a timing light but some older gear heads will tell you how to do it by ear if you have to

What is TDC? When the nuber one piston is in the firing position with both valves closed.Pull spak plu hold finger over hole till you feel pressure then on the front of engine line up mark and the 0. unplug the coil first also get a buddy. once he shows you you will get it get a manual too see if that helps you.

 

[Bondo]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

I been unemployeed for 1.5 year. I'm really broke. so its hard to take to mechanis and just pay him to fix problem.

Ayuh,... We appreciate your situation,...
But,...
When you say this, there ain't much We can do for ya,...

Don't know how to do this.

I still doubt it's the valves, or their adjustment...
By your discription,... It's Detonation...
Continue to run it that way,+ you'll have a boat Anchor, instead of a motor...

 

[ziggy]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

you need to get the service manual for your rig. we still don't know what year. in it you'll find the facts.
you may need to find a friend to help you if your not familar with what tdc is or how to adj. your timing. . timing adj. can be found in the serivce manual and tdc is top dead center of piston travel. the point where a piston changes direction from going up to going down. it's at tdc.

basicly speaking the recomended oil by mercruiser is 25W-40 for all engines best i'm aware of.

while there's much better techs here than me. i'm inclined to go along with Bond-o's assessment. detonation. and if that's the case, ya better not run it till ya get it to stop or you'll be needing lots of bread.

the proper valve adj. procedure is in the service manual too.

ya gotta have a service manual to do any work on your rig. w/o it. your just plain blind as to what you need to do to make it work proper.

 

[cbr1574]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

Mercruiser 140 HP
Year - 1986
Motor Serial - Starts with A
Just did Tune-UP
New Cylinoid, Rotor, Distributor Cap, Spark Plugs, Spark Plug Wires, Points

Oil - Rotella 15W /40 - For better compression

I hope this will help alittle more, as you guys requested.

Thank you, Once more

 

[cbr1574]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

Mercruiser 140 HP
Year - 1986
Motor Serial - Starts with A
Just did Tune-UP
New Cylinoid, Rotor, Distributor Cap, Spark Plugs, Spark Plug Wires, Points

Oil - Rotella 15W /40 - For better compression

I hope this will help alittle more, as you guys requested.

Thank you, Once more

 

[Bondo]

Re: Valve Noise - Merc 140 - 3.0 - Please Help

Ayuh,... Click Here...

 

[cbr1574]

Where should time the boat?

Where should time the boat?

Where should do the timing off the water on drive way

or

In the water while im Running the boat.


Thank you guys. Don't know what i would have done.

 

[Bondo]

Re: Where should time the boat?

Re: Where should time the boat?

Where should do the timing off the water on drive way

or

In the water while im Running the boat.


Thank you guys. Don't know what i would have done.

Ayuh,... It don't matter...

 

[cbr1574]

What the best Oil?

What the best Oil?

If the Rotella 15W/40 is not that good. It turns to water in south Florida weather.

Whats the best oil to put in engine.

Please, keep in mind the following:

Location - South Florida - Hollywood
Year - 1986 - OLDER ENGINE
Engine - Mercruiser 140 - 181 CID
Propeller - 14x19P - Hustler
Out Drive -Alpha 1
Boat - Sea Ray - 19 ft. - Seville II
Carb - MercCarb

Current Oil - Shell - Rotella 15W/40

Thank you, once more