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Over heat problem

S

sticky

Regular Contributor
"hi all new water pump,tstats,

"hi all new water pump,tstats,head gaskets,back flushed,run 15min got hot,let cool then run all day no problem,next day run low speed 20min,opened it up 5 min,got hot,let cool,then ran all day no problem,i dont know"
 
"sorry 89 90HP,new water defle

"sorry 89 90HP,new water deflectors,everything new to do with cooling system"
 
How is the seal between exhaus

How is the seal between exhaust boot and lower unit.
Any chances of exhaust leaking into the pump?
 
"morten that is the only thing

"morten that is the only thing did not change,it was like stuck in there,pulled it out but put it back in,would that cause over heat"
 
"I would have changed it, one

"I would have changed it, one never knows. If compressed and burned, exhaust may go into the water pump.
Is the tell tale 'solid' or sputtering like mixed with air?"
 
"What about the bleed hole bet

"What about the bleed hole between the thermostats. If that is blocked, an air pocket may build up and delay the reaction of the thermostats.
(thermostat housing has to be removed)."
 
"I vote bad thermostats. If i

"I vote bad thermostats. If it were mine, and the problem persisted, I would try a different set."
 
ive stated my theory on outboa

ive stated my theory on outboard thermostats before .just for the sake of arguement remove the thermostats run engine in a test tank or on the trailer.flush ears etc should never be used to identify overheat problems.
find a different overheat guage or buy a infra red gun to get exact engine temps.
 
Comment to the above (just

Comment to the above (justaspark):
Remove the thermostats but do not forget to buy a new rectifier as the risk is big it will melt down in a short time due to lack of water cooling!
 
"i dont think 2 sets of new ts

"i dont think 2 sets of new tstats could be bad,ive put all 4 in water heated all opened same time"
 
unless your in ice cold water

unless your in ice cold water year round and need your engine to warm up to optimum temperature for preformance in cold water thermostats are another obstruction preventing the constant flow of water to the powerhead.
 
"my theory is aquired by years

"my theory is aquired by years of training on all 2&4 cycle engines,marine&s.engines both marine outboard /inboard applications also an associates degree in small engine technology.not to mention the the 40 plus years of hands on experience ive aquired in failure analysis,and repair of marine engines of all makes and models."
 
many manufacturers swear by th

many manufacturers swear by those little demons but i have my own theory i am not telling people to void any warranty by removing them thats not my message just my theory joe
 
"engine base gasket blown suck

"engine base gasket blown sucking air has been the other cause of engine failure,along with water in crankcase causing carburetor problems,lower crank case main bearing seal failure could also contribute to overheating or lack of water to coolant system besides blockage in passageways/exhaust plate corrosion etc..a cool running engine should not harm a rectifyer in subzero temps.some protection is relyed upon by the radiant heat gradually being dispursed by the engine to the parts in direct connection to the powerhead.late models have more alloy vs metal.and do not hold the heat an early model outboard would.this is all i really know about metalurgy.,i do not believe i will ever know it all,but im still trying lol joe"
 
"The following is taken from m

"The following is taken from my database and is not to be construed as being insulting or critical in any manner, Simply an informative entry.

(Thermostat Purpose)
(J. Reeves)

Many engines are considered high performance engines and demand a thermostat(s), and many smaller hp engines also require a thermostat for the following reason. The pistons actually distort/twist off round when running. The thermostat is required to keep the outer wall surrounding the steel cylinder, and the cylinder wall itself at a temperature to compensate for the distortion.

With the thermostat removed, the difference in temperature between the inside the cylinder and the water jacket quickly reaches a point whereas (in effect) you have a oblong piston running up and down a round cylinder, or vice versa. Bottom line is without the thermostat, the piston and cylinder wall could be damaged in a short period of time.

The thermostat in your car isn't there simply to have the heater function properly..... think about it.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
"we can argue this point till

"we can argue this point till the cows come home but the facts are 10 billion loss to manufacturers due to warranty work due to thermostat failure.new powerheads,hours of labor billed to who?marine manufacturers!!!thermostats are needed till the industry can develop something less detrimental to its cooling system.
they are scrambling as we speak to design something more reliable.no foolin."
 
There is no arguement. I state

There is no arguement. I stated a fact presented to me by an engineer. Made sense to me.(EOF)
 
"took it out today,wot 20 minu

"took it out today,wot 20 minutes got hot i shut it down let cool,same thing wot,20 and hot again"
 
"can you run without tstats or

"can you run without tstats or not,i can cruise all day 3500-4000 rpm wont get hot"
 
"hi all well ive run motor all

"hi all well ive run motor all week,new symtoms,now i know when its gonna over heat,if i gas on it and it bucks,it will get hot,and if it dont buck it wont get hot,almost seems electric,"
 
The bucking indicates an ignit

The bucking indicates an ignition problem. If the timing is jumping around it could cause a cylinder or two to get hot and this could cause the engine to heat up. My guess is that the bucking is caused by a faulty power pack.
 
"it will buck just 1 time duri

"it will buck just 1 time during takeoff then overheat,so if timing jumps it will get hot? why do you think just sometimes,first i thought it was prop hub slipping,do you think p/p is going out or wire or plug loose"
 
"i think,..u have 2 prob's

"i think,..u have 2 prob's going on....a missing,or bucking,will not cause overheat,normally,if caused by fuel/ign prob...if u have a mechanical prob,yes.."
 
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