If I remember right, for the 260 and 280 2.5's, at idle somewhere around 15 PSI and 30 PSI at higher RPM. They don't have a normal thermostat, more like a block off plate with a small hole in it.
ut of the block and clean the corrosion up. Get a new 15 and 16 and make sure the plunger #14 seats in the grommet and is free to move. Yours is stuck.my 280 and My drag 300 are dry-stacked,so we pull extra/larger outputs from lower block (2 bolt cover plate).these are 3/4" feed tube which is higher volume/lower pressure...with that being said,i only have 2-3PSI at idle 6-8psi at midrange and 12-15 at 8000
Could you send me pics of this? I would like to do this next week. Bought a bunch of parts from PPE.
will do,basically you tap/plug or weld the two 3/8" holes in exh plate adapter that flood exhhousing/water pump (requires powerhead removal).to keep pump housing from melting i drill like 3/32" hole in copper feed pipe to powerhead.you have to drill this hole lower then the alighnment pipe.this way it fills/floods pipe constantly and dribles down on pump to keep cool.now you have to relieve that volume/pressure elsewhere (drill tap poppet cover for 1/2" elbow) and i will send pics to show details
All the bridgeports, 260/280s/etc idle at near zero and should be 12+ running. If your drystacking make the dump tubes long enough towhere the water exits down over the bearing carrier, your prop shaft seals and gear lube will thank you.
thanks for correction on water pressure!i dont use any tubes and havent for decades (completly dryed up),just the 3/32" hole on copper 3/4" feed that dribbles into alighning tube and splashes down on pump housing....maybe the offshore 15" housing with snout cut off relieves most of hot exhaust before it gets to seals and oil??
That old 2 liter will run forever if you take care of it.Wanted to thank everyone that contributed to this thread. Especially HTS4ME.
Was a bummer to lose the 120 Force on the second outing after buying this old pontoon.
Was both fun and a learning experience picking up and swapping this old Merc on. Not sure how long it will last but I’m only into it for less than a grand. If I could find one more it might be fun to make the pontoon a twin.
