Where/how on the block do i install a water pressure guage on a 1977 75hp evinrude with hustler exhaust?
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Where/how on the block do i install a water pressure guage on a 1977 75hp evinrude with hustler exhaust?
could drill into the water cover on the head,right under the thermo ,:cool:,gots one set up maybe can gets a shot
depends on routing of water.Quote:
Originally Posted by tunnelvision07
Was always watching temp
At discharge hose.
dont put pressure guage in the motor put in the gearcase,,, i was running bass case put pressure guage in at top of block smoked it,,, rex hall and others that i questioned said put in gearcase,,, they where right,,, i dont run a waterpump,,,,,
The old man at the shop and his son showed me some outboard drag tricks the used on their Yamaha v6.Quote:
Originally Posted by tunnelvision07
They wanted to have engine cylinders at operating temp approaching start.
cylinder heads about 10 deg cooler and
exhaust chest a little cooler.
The cylinders "block" , cylinder heads and exhaust chest had common water feed at lowest point as practical and independant discharge at high point of each.
the water feed from gearcase had a pressure relief valve so water flow thru block did not spike at high speeds.
the exhaust chest water was restricteack to stabilize temp at low speed at start and then allow water temp in chest to spike about half way through the race..other thing was thermal coatin inside exh runners and on outside in water chest, this caused surface temp of runners to rise fast helping to tune exhaust for top end. other trick was to make exhaust snout extend past cavitation plate so rooster tail from prop would increase exhaust squeeze "back pressure" at higher speeds. exh back pressure will kill acceleration as engine hits power band but helps at top end. watercraft race systems use water feed off pump routed to stinger to vary back pressure:)
the cylinder temp was stable through out and cyl head actually cooled a bit to avoid detonation at top end.
finally there was a check valve so when engine was shut down it held the water.
also helped meet min weight :)
they did all this on their dyno with sealedwater supply tank pressurised to simulate force feed at speed using water temp to tune exhaust.
um, i'm thinkin water pump, top of the water cover, before the pop off valves, under the thermo:cool:
You drill the block right on top where its flat just inside of the exhaust cover, some of the earlier blocks actually had a plug there, the later block we actually put the water indicator there to act as a vent
thanks for all replys and explaining on the different circumstances guys! were you able to find pictures fast fred? bill gohr are you talking about the flat spot on top of the block, left of the serial number plug?
:eek::eek::cool:
If you look at the very top of the exhaust cove, from the side, it is flat at the top, go to that area in the block about a half inch in from the gasket surface and put it there, it is a great spot for the water pressure, as well vents air out of the system the best, If you look at the 56 cubbers thats where we put the water indicator hose for that reasonQuote:
Originally Posted by tunnelvision07