[C320-list] Another Perkins M30 Overheating Help Thread

Fri Jun 9 08:47:59 PDT 2023

You might try running the engine without the cap on (apologies if this has
been suggested). It sounds like air in the coolant. There is also a
no-spill funnel that you can use with coolant to make sure there is no
trapped air. This involves filling the funnel with coolant and running the
engine and letting air bubble out. It might be getting into the system
through the cap.

Is it also possible you are over-propped? I know you just installed a new
prop and the problems also just started. Either too much pitch or size? I
am sure, based on the list of stuff you have replaced, that this is not an
issue. But, I have a max prop with adjustable pitch, and the previous owner
(or me the last time I serviced it) set the pitch too low.

Good luck. Let us know if you figure it out.

Jeff Smith, #121

On Fri, Jun 9, 2023 at 9:54 AM Dave Hupe via C320-list <
c320-list at lists.catalina320.com> wrote:

> Looks based on your photos like some minor coolant leak around the
> "radiator cap" neck on the heat exchanger tank. The cap looks
> original/rusty. So, wouldn’t hurt to replace it (7psi is what is spec'd).
> However, without seeing a trail of coolant leakage there, I am not sure
> that is your problem.
> I have heard about blockage in the exhaust elbow causing overheating. Any
> consideration of that?  I replaced my entire heat exchanger tank because
> the "radiator cap" neck on the tank had a piece cracked off where the cap
> should seal.  I had to remove my exhaust elbow attached to the tank and
> remount it on the new tank.  I carefully inspected my elbow and it was very
> clean and seemed fine to reuse.   My boat has always been in freshwater.  I
> don't see on the hull roster or your posts where you are located
> (saltwater??). That can make a significant difference related to items like
> this.
> Dave Hupe
> 1994 C320 #32
>
> Sent from Yahoo Mail on Android
>
>   On Fri, Jun 9, 2023 at 1:42 AM, Paul Hetherington via C320-list<
> c320-list at lists.catalina320.com> wrote:   So still trying various
> suggestions here and have ordered a fresh water
> pump.  But we put a clear hose on the fresh water loop today and it's very
> obviously circulating water.
>
> We thought we had maybe fixed the overheating after really running at high
> revs the other day for testing of the prop (dislodged something?) so did
> some measurements/testing.  Unfortunately the temp climbed to 200 after
> about 30 minutes at 2700.  It dropped back down to 180 after 20 min at
> 2000, and then climbed back to 185 after 30 minutes at 2500.  Not sure if
> it had plateaued because we had to come in.  But clearly still have a
> problem.
>
> Any chance a small leak in the rad cap could cause this?  Here are some
> pics.  We can't see  a leak, or water coming out but it looks corroded and
> we are trying anything at this point.  What is the best way to test this
> out?
>
> Pics here:  https://photos.app.goo.gl/E83NV9cPXe6JFXXZ8
>
> We are getting pretty discouraged at this point.  The boat is usable, but
> the month long journey we have planned for this summer is going to be tough
> with 4 knots through the water.  Especially because some of the passes up
> here can be 8 knots (really have to time it!).
>
> Thanks, Paul.
>
> ----------------------------------------------------------------
> Paul Hetherington
> Seasun, 1994, Hull #155
>
>
> On Mon, May 29, 2023 at 7:27 PM Paul Hetherington <paul at heth.ca> wrote:
>
> > Some good thoughts here. Thanks to all.  Will be trying a few things.
> >
> > One thing that has come up, how would we best confirm the non-raw (so
> > fresh) water pump is working well?  There is no impeller that I know of,
> so
> > not entirely sure how the water is 'pushed' around the circuit. It would
> > stand to reason that if this water isn't moving well then the cooling
> > transfer won't be efficient and the temp would rise.  I'm just not sure
> how
> > to best test this.
> >
> > Cheers.
> >
> > ----------------------------------------------------------------
> > Paul Hetherington
> > Hull 155, 1994 Seasun.
> >
> >
> > On Mon, May 29, 2023 at 1:08 PM Dan Winsor via C320-list <
> > c320-list at lists.catalina320.com> wrote:
> >
> >> Here's my two cents worth...
> >> If the engine can't transfer its heat to the raw water then the raw
> water
> >> would be cold when it enters the exhaust elbow. If that's the case then
> >> swap out your new water pump. I don't believe in coincidences like that.
> >> Dan Winsor
> >> Lucky Devil #109
> >>
> >> On Mon, May 29, 2023, 15:41 P.F. Ross via C320-list <
> >> c320-list at lists.catalina320.com> wrote:
> >>
> >> > Paul,
> >> >
> >> > Your experience sounds very much like mine.  I run at 190 at 2700 rpm
> >> > cruise (I have an Autoprop) and have done all the things you have,
> >> except
> >> > for doing the temp testing with a non contact thermometer.  It has
> been
> >> > this way for many years and over those same many years replacing the
> >> temp
> >> > sender has been on my list.  I figure it is the only thing I have not
> >> done.
> >> >
> >> > I watch the temp gauge like a hawk, but it has always held steady at
> 190
> >> > except for once when I sucked a plastic bag into the raw water intake.
> >> So
> >> > at least I know my temp gauge moves!
> >> >
> >> > Frank Ross
> >> > Beta Wave #206
> >> > Naples, FL  34102
> >> >
> >> > On Mon, May 29, 2023 at 2:26 PM Dave Hupe via C320-list <
> >> > c320-list at lists.catalina320.com> wrote:
> >> >
> >> > >
> >> > > https://www.parts4engines.com/perkins-perama-m30-water-pump/
> >> > > This would be the engine water pump.
> >> > > Dave Hupe
> >> > > 1994 C320 #32
> >> > >
> >> > > Sent from Yahoo Mail on Android
> >> > >
> >> > >  On Mon, May 29, 2023 at 3:02 PM, Paul Hetherington via C320-list<
> >> > > c320-list at lists.catalina320.com> wrote:  Yes our M30 is running
> hot.
> >> > > 2500 rpm = 190, much over that and it pushes
> >> > > over 200.  Haven't had the guts to push it right into triggering the
> >> > > overheating alarm (203? - not totally sure it's functioning).  But
> we
> >> > used
> >> > > to be able to run at 2700 with no overheating (185-190) and now it
> >> heats
> >> > up
> >> > > very quickly.
> >> > >
> >> > > I am pretty sure I have read all the previous threads and tried many
> >> of
> >> > the
> >> > > suggestions but we are still stuck, so posting our detailed approach
> >> is
> >> > > only to clarify it to myself, but hoping to get some insight/ideas
> >> from
> >> > > your experience.
> >> > >
> >> > > Here is what we have tried:
> >> > >
> >> > >  - Checked the raw water intake and all was clear.
> >> > >  - Removed hose between seacock and water filter and confirmed good
> >> > water
> >> > >  intake flow through seacock
> >> > >  - Diver conformed no obstruction from below at the entrance of the
> >> > >  seakcock
> >> > >  - Topped up the coolant
> >> > >  - Replaced the impeller
> >> > >  - Replaced the thermostat (Even though the old thermostat was
> >> working
> >> > >  fine when I tested both of them in boiling water)
> >> > >  - Took out the heat changer and cleaned in a bath of muriatic acid.
> >> It
> >> > >  was then very clear.  It was not that clogged up to begin with
> >> though
> >> > >  - Replaced the exhaust elbow (after ordering one with current
> >> > downstream
> >> > >  tube diameter)
> >> > >  - Replaced the raw water hoses between the intake seacock, between
> >> the
> >> > >  raw water filter and the water pump with new reinforced hoses to
> >> make
> >> > > sure
> >> > >  that they are not collapsing
> >> > >  - Kept testing the engine in forward gear, tied to the dock, and
> >> > >  measured temperature with heat gun all over engine block, to
> >> confirm it
> >> > >  wasn't a gauge issue.
> >> > >  - When engine was ran at 2500 rpm or higher, measuring temperatures
> >> > >  between 195 and 200 around the coolant pump
> >> > >  - Always seemed to have good water flow coming out of the boat
> >> > >
> >> > > Right around the time we started to have overheating issues two
> other
> >> > > events happened that may or may not be related.  We switch from a
> >> tired
> >> > and
> >> > > chipped 2 blade prop to a 3 blade Campbell Sailer prop AND the water
> >> pump
> >> > > was leaking so we replaced it with this one from parts4engines:
> >> > > https://www.parts4engines.com/perkins-perama-m30-raw-water-pump/
> >> > >
> >> > > Any help is appreciated.
> >> > >
> >> > > Cheers.
> >> > >
> >> > > ----------------------------------------------------------------
> >> > > Paul Hetherington
> >> > > Hull 155, 1994 C320
> >> > >
> >> > >
> >> >
> >>
> >
>
>