It won’t hurt to run while these hoses are disconnected? They are just drain correct?
It won’t hurt to run while these hoses are disconnected? They are just drain correct?
I would only do it long enough to verify that the thermostats are currently opening, while on the motor.
Ok disconnected the hoses ran the engine and it overheated with no sign of thermostats opening so it’s either bad stats ( both btw) or its not getting water to the heads ,but when I rev it up it cools down this issue is only happening at idle
Don't see how increasing motor RPMs will fix a thermostat problem. Really sounds like an impeller issue to me. The impeller depends on blade flex at low RPMs, but can pump some water at higher RPMs due to centrifugal force even with the impeller blades broken off... I'd start at the source and work up...
2008 Bass Cat Pantera Classic
2014 Mercury Pro XS 200
I would do a STATIONARY lake water test, sounds like your muff set-up is not supplying the proper amount of water, or your water pump installation is NOT working.Originally Posted by Bowfisher08
I had the same problem, it was caused by a faulty water pump base. When I got the boat I changed the impeller and housing, apparently the housing I used was the wrong one (got it from a dodgy marine supply house) which reduced my water pressure. Boat ran amazing at speed, as soon as I slowed down to come into my marina I would get the solid alarm. Gave up and took it to a merc mechanic - he replaced the whole housing with a new one, charged me $150, water tested it and its run amazing ever since.
What temp should they open ? Gauge was showing 150 deg f when the alarm tripped Its a over heat ( check water inlet ) I have made sure the inlet is clean and clear of debris or mud/ sand
the poppet valve from what I read kicks in after 1500 rpms , the water pump housing and all is new , stats are in good working condition I just pulled them again to make sure , I’m gonna compare the new housing to the old and make sure it’s identical
Thermostats open around 135*.
The poppet valve opens when the boat is on plane.
The poppet valve has no bearing on why your motor OVERHEATS @ Idle speed.
What is your water pressure @ idle?
Like 1# maybe
I’m startin to rethink my gasket placement under the power head maybe I got it flipped the wrong way ??? I’m about to pull it and look I guess
It is most likely the gasket. You have pressure up to the adpater which is where the wp sensor is and that is why it is not giving you a low wp alarm as soon as it starts.
The poppet valve is a pressure relief valve to prevent an over pressure situation. When it opens it diverts the excess water back to the source via the lower unit. If it is not seating completely it could cause a low flow at idle but you would get a low wp alarm.
Last edited by leo13; 03-18-2018 at 09:00 PM.
I hope you have better luck with this than I have. I went thru this last year. Found a pencil size hole in the adapter plate under the upper motor mounts. So I replaced the adapter plate, all OEM gaskets, water pump, thermostats and housings (older motor and the thermostat upgrade had not been done) upper motor mounts/ cover plate, poppet, etc. Still overheats at idle and still have water coming out of area under lower cowlings by the upper motor mounts at WOT. Water pressure great at idle in the water but will sound overheat alarm/ guardian at 180 deg on the Smart Speed gauge at idle. Increase RPM's to around 1,200 in idle speed zone and cools right off. Replaced the adapter plate and power head gaskets 2 times (new gaskets both times). Still no joy. Have to either go faster in the idle areas than supposed to or pop the release on the shifter an rev to 1,200 to cool off several times. Long idle speed zone. The adapter plate for my motor is NLA and has been superseded several times ( Serial # 0T075663). All areas were checked for level each time installation was done. Totally lost. Tired of dumping all this $$$$ into this old motor. But only has 565 hours and runs great. UGH!!!
Last edited by Jstep; 03-21-2018 at 08:52 AM. Reason: Added Information
Sounds to me like you never took out the carrier out of old exhaust plate and put it in new one. Now grommet has nothing to seal against. This will cause water not to fill up block just runs out poppet causing over heat at idle.
04 521VX 250 Pro XS
14 521C 250 Pro XS
Apologies! I by no means meant to hijack this thread and should have been more clear. My intention was to take the time to do everything by the book, clean all surfaces carefully and meticulously and check everything for square and level. Also use the proper torque sequence for your motor. The job itself is not that difficult but I found the challenges are in the details. Take your time and double check everything. These one use gaskets hurts the wallet after a while. BTW, I also replaced the carrier and grommet with the poppet kit. More parts were replaced than listed but attempted to shorten the comment to an extent. I went thru this process 2 times with no success, still overheat at idle and have water coming out around the upper motor mounts at WOT. I have been told gotta be a gasket leak for that to occur. Best of luck!
Bowfisher, please post the culprit when this is resolved. I have been having similar issues with an older optimax and am tired of dumping money into it. Use 'qualified' mechanics for the work and still no good results. Not sure I can ever buy another optimax. The aggravation and pocket book can put up with it.
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