Author Topic: 350/260 merc water in oil  (Read 193 times)

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Offline trlake

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350/260 merc water in oil
« on: September 20, 2020, 08:28:13 AM »
Hello, swapped old log style to new sierra center rise exhaust, getting some water in the oil, does the hose routing change or thermostat housing? water seems to come from the center exhaust port and is sucked in thru valves, standard camshaft, all gaskets are good. testing this engine on a stand with a garden hose, to much pressure? tested engine with car headers and a radiator no water in the oil. Anybody had this issue? thanks for any advice.

Offline Plugcheck

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Re: 350/260 merc water in oil
« Reply #1 on: September 20, 2020, 09:32:49 AM »
I've been told water pressure from a garden hose can have this effect.  Important item to check would be the gaskets and type used at the collector joint.  Some systems are dry joint (have a small hose at the joint), or a wet joint where water travels through slots at the collector joint.     I've never checked or known what typical water pressure is when operating on a lake, and never had an issue on muffs, but directly pressuring the engine on a stand with a hose, I'd guess maybe 25 psi?   I'd start low and open the water valve untill the water out the exhaust is just about too hot to put your hand in.
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude

Offline still_fishin

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Re: 350/260 merc water in oil
« Reply #2 on: September 20, 2020, 03:58:58 PM »
Hello, swapped old log style to new sierra center rise exhaust, getting some water in the oil, does the hose routing change or thermostat housing? water seems to come from the center exhaust port and is sucked in thru valves, standard camshaft, all gaskets are good. testing this engine on a stand with a garden hose, to much pressure? tested engine with car headers and a radiator no water in the oil. Anybody had this issue? thanks for any advice.
I had this same issue earlier this year. Too much pressure. 

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