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Starbrd riser hotter

T

terrapin24h

Contributing Member
Hey Guys--
Im getting my boat ready to sell and ran it on muffs today. Last time i ran it on muffs(winterize day last year after not running it all year) the starboard side exhaust riser/header(mine are the one piece style) on my 4.3 was hotter than the port side. I thought it could be because we don't have the best water pressure at the house and i noticed my muffs looked a little mis aligned. So today when i fired her back up, i noticed that the behavior was the same. The one side was bone cold, then the other side was warm. As i let it run, things progressed the same way. At the gimbal, i had "alot" of colder water coming out one side, and a little warmer water coming out the other. I don't think i've ever noticed her running like that before. When i first noticed it last year, i seem to recall the temp guage not running overly hot or anything(180s i think). Today i didn't let it get any where near that for fear of there being a cooling issue. I'm thinking about pulling the header tomorrow, but want to check with the wizards first. I winterize by letting it get hot, then opening the drains. Then fill with -100...I fill the motor via the coolant line fromt he tstat housing, then i do the same for the headers--all around until i see the AF come out the drains. I then replace the plugs and filler up. I am paranoid about freeze damage so this is the best way i could figure to do it without dipping the stern in a 50gal drum of the stuff.

let me know what you all think, sorry for the book. Thanks!

--chris
 
one side always runs a little hotter then the other just the nature of the animal.

Also the one relief hole starboard side shoots out warmer water, the port just a little spray and colder, thats also the nature of the beast.

Did you check the t-stat ? It maybe frozen half closed ?

I don't think you really have a problem unless it goes near 190, then you have a problem, you should be running a 160 t-stat.

I didn't see what year this motor is. Ever change the mani's / risers ?

See you probably, maybe can go with a 2 piece mani riser setup.

Ok if this was my boat, i would change out the impeller in the drive, then a new t-stat 160. Run it on the water if it doesn't touch 190 your good to go.

If it goes to 190 and starts to endge up over stop the boat let it cool off. and limp back home.

Then it's time to yank the riser mani's, to check them or replace and make sure you check the shutters / flappers one might have fallen down and blocked half or the whole exhaust, thats very important, cause it could be your whole problem, sounds crazy maybe to you but believe me the flapper / shutter could be the problem on alot of boats running hot.
 
thanks for the comfort Chief!!! My 502 mpi does the same thing on the muffs. Starboard Hot, port cold. Starboard exhaust spits and steams while port is cool and flows. Temp goes to 170, then opens and drops to 165. I went thru every hose and good water flow throughout the system. New impeller.
 
What year 4.3L? Fresh water or raw water cooled? 180 F. is too hot for a raw water engine. Diverter hole inside the T'stat hsg. may have closed up some.
 
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