Chuck wrote:

Hi Finn

I don't get any water pressure until temp get up to about 150, about 2 lbs.
at 160, 8 lbs. at 180.
I don't think the water pump develops enough pressure to register on the
gauge. Come to think of it, the only pressure it could develop would be
between the inlet and outlet of the pump, it wouldn't pressurize the system
relative to atmospheric, which is what your gauge is measuring. I think the
system pressure comes only from expansion of the coolant. Is your gauge
electric or mechanical? Mine is mechanical and it kept plugging up the 1/8"
tubing between the engine and the gauge with debris from the coolant. I
fixed that by installing a small inline bronze filter sold by NAPA as an
inline air filter for air tools. I installed it at the thermostat housing.

It might even be a good idea to put a filter in front of an electric gauge
sender - it could plug up too. Seems like theres a lot of crud in any
(water) cooling system.

If you suspect coil overheating you could get a remote reading digital
thermometer from Radio Shack and stick the remote probe to the coil(s).They
should stay below 160 degrees. I think the coil makes heat in a linear
relationship with RPM.
I bet if you fix your muffler and your gauge you can go flying again.

Chuck Dunlap

Thanks Chuck.

Water temp sensor is mounted just under oil filter pad in the drive end-housing
and so the the water pressure sensor (with about 4" hose to the electronic
sensor). When running it on the ground I did get a pressure reading. A temporary
blockage (or intermittent wire failure to the sensor) seems likely.

Temporary ignition coil failure seems likely. Coming to think of it, could have
been the same situation that occurred at 25 hours when I blew out my old muffler
(when I still had one under the carbs). Very similar situation then - full
throttle and leaning. Is it possible that misfiring could put extra stress on the
muffler?  Maybe un-ignited gasses from one rotor getting ignited in the muffler
by the exhaust from the other rotor and burning/exploding in the muffler?

I'll move my RS temp probes over onto the coils.

Finn

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