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-   -   1990 Mercruiser 454 magnum overheating, stumped! (https://www.offshoreonly.com/forums/general-q/371730-1990-mercruiser-454-magnum-overheating-stumped.html)

SabrToothSqrl 06-01-2021 01:04 PM

Ohh man. self inflicted wounds are the worst!

SB 06-01-2021 01:16 PM


Originally Posted by SB (Post 4791468)
Speaking if which (looks like good flow) And we have all heard many over the years here heat up on the hose but not in the water.


Originally Posted by liberator221 (Post 4791482)
If you are running faster than idle speed many home water systems don’t have enough volume to keep up. ( as sb said)


Originally Posted by snapmorgan (Post 4791561)
You need to put the boat in the water and try it. You are most likely chasing a problem that doesn't exist.


Originally Posted by 90MirageTrovare (Post 4791997)
Well I guess snapmorgan was right! Ran all day yesterday around the pnw sound. No overheating problem. Thanks everyone for all the advice, at least I know my boat a little better now 🍻

#norespect

Wink: lol:

zz28zz 06-01-2021 02:22 PM


Originally Posted by SabrToothSqrl (Post 4791962)
Air: Problem: https://www.youtube.com/watch?v=EQOOskTLK90
No Air: No Problem: https://www.youtube.com/watch?v=Z65wRy-ShwU

you run a hose first from water IN to make sure air isn't getting TO the engine. If that's clear (no air), then move on to water leaving the engine. Mine had air. (bad!).

That's not bad at all. I would be looking for a continuous stream of bubbles.. That just looks like some random air pockets getting purged out. Glad to hear ya got it resolved.

90MirageTrovare 06-01-2021 03:06 PM

All the respect!
 
SB and liberator221 you guys are gods! Thank you for your knowledge. Being new to the game I’m sure I will be coming back to you guys for advice.

90MirageTrovare 06-01-2021 03:09 PM


Originally Posted by SabrToothSqrl (Post 4792000)
Ohh man. self inflicted wounds are the worst!

SabrToothSqrl you got that right 😂

liberator221 06-01-2021 03:14 PM

Great to hear your boating. I learned something from AllDodge also about running them in a bucket. Had no idea. That’s why I set around and read this stuff.

fishingdave 08-14-2021 01:25 AM

can you do a video a little bit closer showing how the water goes out to each of the risers from the thermostat ports ? or cut it in half so we have a closer look lol. i am having the same issue on a 4.3l.

90MirageTrovare 08-15-2021 09:20 PM

Have you put it in the water? Not sure if I was chasing a ghost or had two bad thermostats but mine is fine now, even idling it 15+ minutes on the hose.


Originally Posted by fishingdave (Post 4801596)
can you do a video a little bit closer showing how the water goes out to each of the risers from the thermostat ports ? or cut it in half so we have a closer look lol. i am having the same issue on a 4.3l.



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