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454 motor riser overheating

H

hayden

New member
"I have a 454 and the risers a

"I have a 454 and the risers are getting very hot.The motor has been rebuilt last year.The motor runs cool, but the one riser is hot.I have replaced the water pump"
 
The riser could be plugged wit

The riser could be plugged with crud if its a few years old. Or the hose to it from the T'stat housing may be plugged or kinked.
The risers should run warm to the touch only.

Rod
 
it'S WATER IN riser but no

it'S WATER IN riser but not going out the exhaust fast enough.is it any way to test to see if it's a blockage from riser out.
 
"I would pull the riser and th

"I would pull the riser and thoroughly flush it out. No big deal, but use a new gasket to the manifold.
Rod"
 
They should run about the same

They should run about the same temp.
There must be some basic plumbing issue such as a plugged hose or a restriction at the T fitting a the T'stat housing. The latter has two spring loaded restriction balls at the outlets typically. I would check those for proper operation. EAsy to check.

Rod
 
mine don't have restrictio

mine don't have restriction balls at the outlets.i picked up a new riser and gaskets today which gaskets should i use the one with two large holes and two small round holes or the one with four large holes
 
"Match up your existing ones.

"Match up your existing ones.
The four large hole ones (unrestricted) are only used if the manifolds and risers are cooled as a unit; ie, no separate cooling hose to the risers.

Rod"
 
i don't have a separate co

i don't have a separate cooling hose to the risers.mine or cooled as unit. thanks for all help rod. i will leave you know if that works. talk to you soon.
 
"I have a mercruiser 5.7 - 199

"I have a mercruiser 5.7 - 1997, Starboard riser is runing hotter than the port riser. The port riser is cool and the starboard is hot to touch.
The hot temp sensor alarm goes of if running at 3600 and stays on. The themostat in this engine is 180 degres. is this to high for the hot temp sensor. Also should there be a significant diff in the temp of the two risers"
 
i don't no about your them

i don't no about your themostat temp but i was told a 454 should run 160 themostat. your risers shoulded run hot. it shoulded be any signifiant temp diffent between risers
 
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