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AQ131A Running hot HELP

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avent

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"Does anyone have any idea whe

"Does anyone have any idea where to start looking for an over heating problem. I had it on the lake yesterday, it ran fine, it just ran hot. By the time I made it back to the boat ramp the engine was around 240 degrees. When I first had it out it stayed around 200-220 degrees. but when I went to an idle the temp started going up and never went down ( unless I shut the motor down). Originally the motor would run at about 180 degrees. then I drove in a shallow lake and sucked up gunk from the lake bottom. I flushed the system out and replaced the impeller. That helped but did not cure the problem. Would it be worth replacing the thermostat or a waist of time and money? Any ideas would be great."
 
"IT could be debris inside the

"IT could be debris inside the outdrive grids, or inside the strainer, or in the heat exchanger, or inside the exhaust manifold.

If you have verified that all those components are clean, make sure the raw water hose connector in the outdrive is not corroded/perforated. For if it is in bad condition, the raw water pump will suck air when the boat is on the plane."
 
"You should have this setup, I

"You should have this setup, I have run into this problem before, even with sucking up weeds. When I see my temp go over 200 degrees. I remove the filer with my hand, clean it out and I'm off and running.
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This setup has been running in my boat for over 10 years now, never had a problem, and has save me a lot of headaches."
 
"Tom- what a great idea!! It&#

"Tom- what a great idea!! It's probably to late for sunrunner Would guess he has an oil cooler full of aquarium gravel.

Your oil cooler is by the starter with a long single bolt and a bunch of "O" rings and little radiator that looks like a boiler.-- The only thing that separates the oil from the raw water and some more bigger "O" rings. You can take them apart and rod out the cores, but take a Valium first.

edit; El this is the water pump with the 2 seal and "O" ring I was thinking about earlier."
 
"Your right! He is probably go

"Your right! He is probably going to have to do that, and clean out every rod that is in his oil cooler. My set up prevents that. The holes in the filter are smaller then the holes in the rods. The idea is the gunk gets caught before it gets to the rods. What nice about this is everything is see through. You can see mud, weeds, and air leaks."
 
"William and Tom, I think sunr

"William and Tom, I think sunrunner'88 will not have a problem with mud or gravel in the oil cooler, since the AQ131 does not have one. At least, not from factory.

Regarding the strainer, that is a nice setup. However, the OHC engines do have a raw water strainer, but it is located after the raw water pump by the coolant heat exchanger."
 
Oh boy- see I can never get th

Oh boy- see I can never get that 131 vision in my head!!! I didn't like that auto motor with those soft timing cog wheels which always looked a little frosty when ever I open one up--But you gotta admire the nice filter tom came up with.
 
"OK I took apart the heat exch

"OK I took apart the heat exchanger and low and behold the fresh water insert (Part# 855453) with in the heat exchanger, that acts as a radiator would on a car, is gumed up with mud. I really don't want to spend $666.75 on a new one. Does anyone have an idea how I would get this thing cleaned out?"
 
"OK here is what I have done a

"OK here is what I have done and still no result. I have removed the heat exchanger and cleaned out the fresh water insert. A lot of old impeller bits came out as well as a lot of mud and little rocks. I took the exhaust manifold off also, cleaned, inspected it and ran copious amounts of water through it, it looks just fine. I replaced the coolant and fired it up. It still runs hot. My next step would be to replace the thermostat, only because I can't think of anything else. Does anybody have any ideas what course of action I should take next? I should point out that I ran the motor in my drive way hooked up to a garden hose. I don't think this would make the motor sore to the temp of 240 degrees f. I also checked the timing and it is a bit off, but I seriously doubt that would be the issue. Any ideas would be greatly appreciated."
 
"The thermostat is not part of

"The thermostat is not part of the raw water system, so I think you are wasting your time and money by replacing it. If the engine was running fine prior to the pump sucking mud and gravel, then your problem is likely on the raw water side. There are so many components there, so it should not be so difficult to find where the blockage is.

Have you tried backflushing from the copper pipe under the exhaust manifold towards the drive? For that, remove the impeller and key from the raw water pump and see if something comes out there when backflushing, then backflush from the pump towards the drive."
 
"Prior to taking the heat exch

"Prior to taking the heat exchanger apart and the ehaust manifold off, I flushed the system. I removed several pieces and did see a large amount of mud come out while back flushing.
While running the motor now, I have good water flow from the raw water end. So at this point I can't really think of much else and I am starting to look at the coolant side. Maybe the water pump is not working or the thermostat is stuck? I am out of ideas."
 
"Thermostats are not notorious

"Thermostats are not notorious for failing in those engines. Again, I would concentrate in the raw water system, but it's up to you what you do."
 
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