[C320-list] Another Perkins M30 Overheating Help Thread

[P.F. Ross]

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
>
>