[alberg30] Re: Atomic 4 sounds

Steve Weingart shw at gate.net
Tue Jun 2 07:11:05 PDT 1998


From: Steve Weingart <shw at gate.net>

Frank,
>
...
>
>Anyway, the Atomic 4 is starting to make a strange noise:
>
>While running it will ocassionally make a high pitched "squeaking"
>noise. It seems to run OK though. My oil pressure gauge reads low
>(around 7 psi) - I haven't yet checked to see if the gauge or sender is
>faulty. The oil is clean and I change it regularly. Could my bearings be
>going ? WOuld synthetic oil protect the engine and bearings better? If
>the oil pressure is low my guess is that more efficient (synthetic) oil
>might make up for reduced oil flow ???

I can't tell you what the squeaking noise is without hearing it, it could
be anything from a slipping belt, which is nothing, to something very serious.

One thing that I can tell you is that 7 PSI, if real, is an absolutely sure
way to trash your engine.  The standard recommended pressure is about 40
lbs at cruise speed, with anything over 30 - 35 being O.K.  Even at dead
slow idle you should have 15 - 20 PSI. (though way down at about 600 rpm my
engine will drop to 10 - 15 PSI, but it's close to 20 at 1000 RPM).  

Running at such a low pressure could/will likely damage your bearings.  You
*really* need to figure out if the sender/guage is bad, or if the oil pump
is bad...or the pump system is clogged.

Did you used to see higher pressure, or is this new?  If you used to see
higher pressure then something is broken (sender, guage or oil system).  If
it has always been this way you could have a sensor and guage that are not
matched for each other...you should check it out...

Nothing (no oil or additive) will protect your motor adequately if there is
too  ittle pressure.  The recommendation is plain 30 weight oil, I have
heard that modern 10W/30 is alos O.K..  Using 1/2 to 1 Qt of Marvel Mystery
Oil in the crankcase and up to 8 oz/12 gal of gas (mixed in) will help keep
the rings and valves free.

There is an oil pressure adjustment on the manifold side of the engine, at
the rear, below and aft of the mechanical fuel pump.  It is a slotted,
headless set screw with a 3/4" locknut (it may have a brass cap nut too,
take it off first).  Loosen the locking nut and turn the screw in about 2
turns, tighten the lock nut.  Start the engine, if the oil pressure is
higher, adjust for the correct pressure by trial and error.  The spring
under the setscrew may have broken/collapsed, so you might check that as an
answer to your low pressure.  If it is not a bad sender.

Don't forget Don Moyer at Moyer Marine.  He is the best source that I know
of for A4 info.  His number is: (717) 564-5748 in Harrisburg, PA.  He is
really great about giving advice on the phone.

Good luck,

Steve

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