[C320-list] Another Perkins M30 Overheating Help Thread

Thu Jun 8 23:41:34 PDT 2023

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
>> > >
>> > >
>> >
>>
>