Engine Cooling

[John Doerfler]

Hey guys,
     Just found this website and I gotta be honest.  I am thrilled that there are others out there like me.  My 83 AM skier is the reason I was put here on earth.  It was my deceased fathers boat and he loved it as much as I do.  Anyway, I cant seem to put a Tstat in my engine without it wanting to overheat.  Engine is a fresh 350, new impeller that works great, and new hoses.  Ron has been trying to give me advice on Tstat location and hose routing but the darn thing wants to get hot every time I try it.  Do you suppose my engine water pump is bad?  HELP!
Kyle Doerfler

[Mike Harry]

Is there any way you can get a digital pic up on the site of your hoses or email it to me or someone if your worried about the routing of the hoses that is. Are you sure you didnt put the T-stat in upside down? Recirc could def be your problem..... are you using the original recirc pump or a new one?

[John Doerfler]

Well,  the hose routing is correct and verified by Ron.  The Tstat position is pointy side up under the 3bolt cover.  The engine coolant pump was installed last year and it wanted to overheat then due to impeller pump issues.  That is when I decided to wait until this summer to rebuild the engine which I have done and had it on the water twice.  Each time I put it on the water and have to remove the Tstat because it wants to creep over the 160 degree temp max of the Tstat.  I have a picture in my personal profile area.  That picture is the old hose routing before Ron corrected that for me.  I think I will just have to buy a new engine water pump and try that out!  Oh yeah, the impeller pump works great.
Kyle Doerfler

[Mike Harry]

Sounds like the recirc pump could be the problem then. Sounds like you have all your other bases covered.

[Joel]

Where is the recircualting pump located???   Mine likes to creep up to 180 or so...  It has a 160 F T-Stat and the impeller is fine.

Thanks,  Joel

[John Doerfler]

Its the water pump on the front of the engine and its the one used in automotive applications.
Kyle Doerfler

[John Doerfler]

Well, I took of the engine circulation pump today and I may have a bad pump.  Word of Wisdom, dont buy remaned parts.  Buy new parts if you can.  I also was told by a local mechanic that you can plug of the bypass port by tapping the hole and inserting an 1/8" pipe plug in the bypass to block it of and that will give you more flow volume.  You dont need the bypass because the Tstat location lends a bypass so you wont build water presure in the engine.  Going to try it out this weekend and hopefully the new pump plus the extra volume will do the trick.  I will keep you all posted.  Thanks!
John Kyle Doerfler

[Mike Harry]

Yeah, I wont buy reman unless I'm getting the kit and doing it myself. Hope you have it licked now!

[John Doerfler]

Guys this engine cooling thing is driving me nuts.  Got a new circulation pump.  Impeller pump sucks a 5 gal bucket of water down in about 15 seconds.  My hose routing goes from the bottom of boat, to the trans cooler, to the impeller pump, then to the cooling block on top of motor.  BUT every time I try to put a 160 Tstat in the engine it wants to overheat!!!!  I have tryed placing it under the three bolt cover like everyone is telling me with the pointy side up but no such luck.  Is there anyone out there that can help me???   My profession is mechanics so I think I am not underqualified for such a task.
John Kyle Doerfler

[John Doerfler]

I was looking at some pics of 350 power plants like mine and I noticed that I may have the hose placement wrong on the front of the exhaust manifolds.  If somebody with a 350 engine like mine would please take a look at my pictures of my motor in my personal album and compare mine with yours that would be great.  John Kyle Doerfler

[John Doerfler]

Tryed the different plumbing on the front of the exhaust manifolds and had no luck.  Still wants to overheat when I put in the Tstat.  Well I guess I will keep investigating.
John Kyle Doerfler

[brandon]

Make sure all your hoses are good.  Sometimes when they are older and get bad, the will blister on the inside and restrict water flow.  Also make sure the water is flowing thru the entire engine and making its way out the exhaust, between debris sucked up and rust flakes from the cast iron, a piece or pieces may be causing a restriction in a port.  I have even seen engine blocks filled with debris so bad you have to disassemble the motor, remove all freeze plugs, and clean out.  Rare, but still a possibility.  Start with the easier stuff and work your way, which it sounds like you have.  Check to see if the water is flowing thru the exhaust manifolds to the risers.  I have found the passages between the two stuffed with debris also, which is where the hot water needs to exit to allow fresh cool water in.
Good luck.

[brandon]

Also forgot a simple one.  Make sure there is no debris stuck in the oil cooler.  These are prone to getting plugged and causing major water restriction (many models have a seawater strainer which will prevent this).  If you had an impeller come apart, did you find all the pieces.  These pieces will sometimes also plug passages.  Again, if the pump is doing its job and the hoses are routing the water properly, there has to be a restriction keeping the water from moving.

[daveo]

I had the same  problem last season. The risers were all plugged up with corrosion.I had to replace both sides. I also replaced the 160 thermostat with a full flow thermostat. my temp actually is a little low (150s) but but shes running good so i didnt try to put the 160 back in. 

[John Doerfler]

Thanks for the advice brandon and davo.  Well all the hoses are brand new.  I just had the engine rebuilt and a machinist here in Hays did great work so I dont think its restricions in the engine block.  The trans cooler is free from debris.  When the Tstat is in I can feel all the cold water wanting to go straight to the exhaust manifolds instead of going through the engine.  Tstat works when I put it in boiling water but it doesnt work in the engine. I gave up on it for a little while.  It runs great without a Tstat however it would be nice to finish the engine rebuild and have everything working right.  Do any of you know somebody who knows these power plants so I can call him and let him know my situation?
John Kyle Doerfler