When I'm just easing along in gear my temp reads 102-142 and it varies. It will get hot then cool right back down and go back and forth within seconds...I have plenty of water pressure...what can cause this
When I'm just easing along in gear my temp reads 102-142 and it varies. It will get hot then cool right back down and go back and forth within seconds...I have plenty of water pressure...what can cause this
You have a thermostat sticking.
Thermostat opening and closing, IMHO. Mine does the same thing, but between mid 100s and mid 130s
So many honey-dos . . . . . so little motivation
Zach:
Thermostat control is only taking place at IDLE speed. There are some conditions (with only slightly elevated RPM's) where the poppet valve may be beginning to open (resulting in lower temps).
Would be curious as to what your water pressure is when the temps are reading lower....
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by EuropeanAM »</td></tr><tr><td class="quote">Zach:
Thermostat control is only taking place at IDLE speed. There are some conditions (with only slightly elevated RPM's) where the poppet valve may be beginning to open (resulting in lower temps).
Would be curious as to what your water pressure is when the temps are reading lower....
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The water pressure guage stays the same throughout the variation in temp. It doesn't change at all. Its a brand new 250 pro xs. Runs excellent! Just kinda curious as to if I should be worried about that
I'm still going with the thermostats opening and closing.
The enigine heats the water in the cooling jacket, the Tstats open, cool water flows thru them, and they close. No water flow, water heats, stats re-open, and so on.
Earlier this year at home with the "ears" on the engine providing water, I had the Tstat outlet tubes disconnected to watch water flow as the engine idled (I was trying to diagnosis a cooling problem), & that's what they did. Flowed, stopped, flowed, etc, with corresponding changes in temp on the SmartCraft.
On a side note, I was surprised at how little water flowed through the stats when they were open. Obviously enough.
Your engine behaves exactly like mine at idle. Seems right to me.
Isn't it cool to have the temp gauge?
So many honey-dos . . . . . so little motivation
Definitely nice to see what's goin on!
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by zack birge »</td></tr><tr><td class="quote">
The water pressure guage stays the same throughout the variation in temp. It doesn't change at all. Its a brand new 250 pro xs. Runs excellent! Just kinda curious as to if I should be worried about that</td></tr></table>
Normally, idle water temps will vary from 120-145. It's not uncommon to see an occassional drop into the 111-119 range, but predominately, it should stay at 120-145.
If not- and water pressure is BELOW 7.5 psi, I'd recommend inspecting/testing thermostats.
Note: If water pressure is at or above 7 psi, you may be witnessing the function of the poppet valve.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by EuropeanAM »</td></tr><tr><td class="quote">
Normally, idle water temps will vary from 120-145. It's not uncommon to see an occassional drop into the 111-119 range, but predominately, it should stay at 120-145.
If not- and water pressure is BELOW 7.5 psi, I'd recommend inspecting/testing thermostats.
Note: If water pressure is at or above 7 psi, you may be witnessing the function of the poppet valve.
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That's exactly what mine does idling in neutral or in gear . I just had some replaced that were sticking open.( Due to some shallow running dredging I did) Now running all out I noticed the temp would vary from 109 to 111 (Lake temp is in the high 50's) and when I'd come off plane it would go up between 134 to 140 and then it would imeadiatly start cycling again.
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