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New 3.0 in older boat

Wait but the with the two hole gasket, there is nothing for it to seal against on the intake. So how would that even work? My original one is the single hole gasket I believe.
 
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John4003 said:
Yes I re torqued everything. I'm following the break in instructions that was sent with the motor and so at this point can't take it above 2k. I'll check the gasket that came with the carb but I think it was the two hole one. Man not sure now but I can see where that would make a diff. Here's the vid of it running before I tried to take the idle down to 700. So here it never went below 1k rpm.
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Watched your video, I would pull off that valve cover and take a look......Something is not happy. Sounds like a box of rocks.
 
Other than the obvious miss, it sounds like all the other ones I've watched and listened to. What would you be looking at under the valve cover?
 
Broken or loose rocker arm. That noise is not normal. I would also check your mechanical fuel pump if equipped.

The shake in your engine is in-time with the awful noise.
 
Brand new engine so I can't open it up without voiding the warranty. It does have the mechanical fuel pump but it's also new. It can't really be put in wrong I don't believe. That noise could be the new fuel pump?
 
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John4003 said:
Marineengines4less.com
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Sorry, Read the whole warranty......this seems like a crappy company.

Copied from your warranty....

a)You must, at your own expense, have the valves readjusted (if necessary), and the oil and oil filter changed after 10 hours of engine use. Failure to have these services performed will void the warranty.

I would contact the company and explain the noise and you definitely have a noise in that engine.
 
John4003 said:
Wait but the with the two hole gasket, there is nothing for it to seal against on the intake. So how would that even work? My original one is the single hole gasket I believe.
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Yeah didn't make sense to me either, which is why I tried the single hole gasket which gave me idle quality issues. If you had a single hole gasket originally and try going back to that and see if it improves idle quality.
 
Docksidemarineservices said:
Watched your video, I would pull off that valve cover and take a look......Something is not happy. Sounds like a box of rocks.
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I could not agree more.

Regardless of what you think you here on youtube videos,
I can say from personal experience with mercruiser 4 cylinders from the '70's to present and have never heard one sound like that unless something was wrong.

Start by trying to identify where that noise is coming from.
Use a stethiscope and see what you find.

As Chris suggests it may be in the rocker area...
Just because you have good compression numbers only reflects
The valves are closed...
That engine should considerably quieter!!
 
Yeah I will do some more digging. In your opinion, what would you be looking at first? If you have heard a lot of these motors running, you must have some idea of what is causing it.
 
I pulled the pump today and didn't see anything out of the ordinary except a leaky fitting. Going to look under the hood and see if there is anything amiss.
 
Broken or loose rocker arm.
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John4003 said:
Results of cold compression check.
#1-165
#2-160
#3-165
#4-165
Pretty consistent.
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John, with these very consistent cylinder pressures, it would be highly unlikely that you have a broken rocker arm.


As for the mechanical fuel pump, your fuel pump's camshaft operated push rod actuates the pump arm at 1/2 engine speed.

 
Why anyone would suggest adjusting the valve/rockers regardless of the method is insane!
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Wow!


John4003 said:
That is what I think also. Did you listen to the video?
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Yes, and it is difficult for any of us to determine what may be wrong from simply watching a video.

Suggestion:
connect your timing light up.
strobe the timing mark while you listen and see if the noise is "In Sink" with the strobe light, or is "Not In Sink" with the strobe light.

The strobe light will flash once for every two crankshaft revolutions.

If this sound occurs twice for one strobe flash, then it would be related to the rotating assembly.
If this sound occurs once per strobe flash, then it would be related to the valve train.

Disclaimer..... this will not be easy to do by ear and sight alone.... but you may get lucky.

 
RicardoMarine said:
John, with these very consistent cylinder pressures, it would be highly unlikely that you have a broken rocker arm.
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That is incorrect.
You are measuring the pressure with the valves closed.
If a loose rocker or other issue not allowing the vlave to fully open would not affect those numbers....

Therefore disregard PCR's usual spew...
 
kghost said:
Rick said:
John, with these very consistent cylinder pressures, it would be highly unlikely that you have a broken rocker arm.
Click to expand...

That is incorrect.
You are measuring the pressure with the valves closed.
If a loose rocker or other issue not allowing the vlave to fully open would not affect those numbers....
Click to expand...


If the OP was to have lost an intake valve rocker arm (causing that intake valve to remain closed) what allows for the incoming air volume that is necessary to create a cylinder pressure of 160 to 165 psi?


.


 
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