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55EL79C overheating

W

wilbor

Member
hello, i have owned this motor for two years, i have replaced the water pump x2, the thermostat x2, poppit valve, head gasket, exhaust cover gasket, all seals that apply. i have not replaced the powerhead base exhaust gasket, cleaned out all ports and passages, pick up tube from pump, rebuilt carbs, reset ignition timing, now the temp alarm might go off after five mins or three hours, i have always had good telltale streem (luke warm) when alarm sounds i feel and inferred the head for overheating, warm but not hot , i also notice i dont get any spray out of the exhaust ports when the thermostat opens, just steam. i suspect a bad sensor.ok, in the factory parts it shows an inner exhaust plate and an outer cover plate, this motor only has an outer plate?? can anyone advise where to go from here..thank you..wibor
 
That mod has a problem with the upper grommet on the water tube.
The rubber grommet was replaced with 2 - two- plastic washers!
Quite a job to change as both power head and exhaust collector must be removed.
If possible buy/borrow an IR temp gun and check the engine temp and temp switch before starting this operation!!
 
i have checked the sealing on that tube and i cant see any leaks, i put pressure in it with air and water and there is no leakage..???
 
that sure is alot of work to get to, when i had the lower unit off and the head off i clamped the garden hose to the pick up tube and it was flowing out of every port like crazy, didnt seem like any blockage....but when the motor is running with muffs on alot of water excapes out of the lower unit ie: small hole on side, back where the mount is, even higher up.?? i guess the only way to know for sure is to tear it down, can you tell me if the sensor is bad do they just stop working or premature set off the alarm..
 
They normally either shorts out or just stays open without alarm.
Best way to test engine temp is by using an IR gun. The very top of cylinder is the most critical as that is where the air-bubble build up if low cooling capacity.
 
I know you replaced it twice, but when was the last time you replaced the waterpump? Did you replace just the impeller, or the whole pump? What condition was the watertube in, especially the end that engages the waterpump?
 
yeah everything has been checked and double checked, now look at the parts breakdown,, year 1979--55hp--55EL79C-- it shows an inner exhaust cover in the parts section..#26 P/N 320724. this motor does not have one..never did. .Question?? is it suposed to ???
 
When you take off the " outer cover " can you see the pistons / rings ????---------------------If that # 26 was missing you would have real problems ------------------I would say your engine block has been replaced with a much newer model !!
 
no i cant see any rings or pistons. someone before me has been into this motor...now i am wondering what the hell year/ model do i have here ??
 
Certainly you do not have a 79 engine block !! ------------------It has been replaced or the bracket with the model / serial # has been replaced.---------------------Time to post a half dozen pictures.
 
yep sure seems like it, by looking at this motor you can tell someone has been into it before me,
the motor runs good, plenty of power, idles good, starts easy. good compression, can anyone tell me if the motor is worth keeping, one guy said the 55EL79C is a commerical motor, or should i unbolt it and find another motor.. numbers i found on block. M25606...331030...FL2420...326100...9160+9160 together on each case...
 
OK, i think i found the problem. where the two exhaust ports exit the bottom of the motor in between them is a water exit port coming from the thermostat/head. the exhaust upper tube bolts to the bottom of the block. there are two small holes on each side of that houseing that were blocked with RTV> now i dont use RTV, i use spraytack, now see if i got this right. if the two holes were blocked and the thermostat opens the water would have no where to go and could not exit the engine.?? in turn setting off the alarm, thats why i had steam exting the two ports just below the powerhead???

pick up tube and seals were ok, used/old but ok,
 
Being a hired wrench for 30+ years i know how value able technical information is but of all the book i have on this motor nothing showed me this issue, hands on experance and the little things you learn that no book will ever show you. ..parts are orderd so when i get her up and running ill post my findings..thank you for your time.
 
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