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have a 1998 90 hp overheat..thermostat replace twice ...head…

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have a 1998 90 hp...
have a 1998 90 hp overheat..thermostat replace twice ...head gasket replaced...check timing with another 90 same 16 idle 61 5500rpms...both were same ..bypass dont get because spring is pushing popet against seat,,water pressure would just make it tighter..read that at 2000rpm it should start to open a dump water..more water flow better cooling ...this is bring on the overheat system and shutting down motor..water temp at idle stays at 165...at about 3000 start to rise at 5500 goes up to 220 in 1.5 minutes something like that...two water pumps installed....if remove bypass lot of water comes out put still pisses out hole
Submitted: 8 years ago.Category: Boat
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Answered in 1 hour by:
6/19/2010
Marine Mechanic: Jeremy R., MarineTechnician replied 8 years ago
Jeremy R.
Jeremy R., MarineTechnician
Category: Boat
Satisfied Customers: 9,020
Experience: Multiple factory certifications 20+ years of experience.
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Welcome, have you tried running it without the thermostat?
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Customer reply replied 8 years ago
no will go and try in 1/2 hour
Marine Mechanic: Jeremy R., MarineTechnician replied 8 years ago
ok, if she runs fine without them, then either the poppet valves are bad or you have salt build up in the motor. Also if you just did and impeller and not the housing, that could cause it, and if you did not seat the copper tube that goes into the impeller housing right, that would do it, also if you did not get the key into the impeller right, because hondas are tricky that would cause it. sometimes i drop the lower unit and use a garden hose on the copper pipe, macing a fake water pump
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Customer reply replied 8 years ago
it runs at 145 with no termostat..what are the poppet valves?
Marine Mechanic: Jeremy R., MarineTechnician replied 8 years ago
poppet valves are the pressure relief valves. but you did buy new Honda t-stats and use them right?
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