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Bayliner 2452 with Mercruser 50 L Riser very hot

S

srazac

New member
"Recently bought a 2000 Baylin

"Recently bought a 2000 Bayliner Cierra 2452 w/5.0 L mercruiser engine used in salt water. Went out once and the exhaust elbow got so hot on the starboard side of the engine that it melted the exhaust tube. The boat was pulled and the both manifolds, both risers, spacers, water pump, and Thermostat were replaced. The boat runs better but the starboard side is still hotter than the other side. Frustrating since I have spend already 2K into this. The mechanic said the impeller in the out drive is OK, but we will replace it again this week for good measure. The port side is fine. The engine gauge always reads 170 not hotter, even when the one riser gets hot. Thanks in advance for your help."
 
"Sounds like your T'stat f

"Sounds like your T'stat fitting or the hoses to your manifolds and risers may be plugged. Since your manifolds and risers are all new, that is about all it can be if the other side is running cool. Thankfully your engine did not overheat during all this.

Cast iron manifolds and risers last as little as 3-5 years, so you did not do too badly. If the boat is moored in the water you can't do much about it, but if you trailer it, you should thoroughly flush it after each use. Everything will last much longer that way.

Rod"
 
Did they replace the exhaust s

Did they replace the exhaust shutters? Could have melted since the tube did; they are next to each other. It could have fallen down into the "Y" pipe and causing a restriction.
 
"Thanks for both feedback. Muc

"Thanks for both feedback. Much appreciated. They did replace both flappers but will have them check the Ytube again and the hoses. I was mistaken, the water pump in the out drive was replace. Not the pump on the motor- driven by the belt. The mechanic thinks this is also a problem , since there a few drops of water coming out the pin hole. Not sure why he did not catch this before. well more money to be spent. thanks"
 
"Rod, How true. I am still try

"Rod, How true. I am still trying to establish if i am related to any oil barons. I can only live in hope.Jon."
 
"update: they boat was pulled

"update: they boat was pulled from the water and the outdrive thoroughly checked. The impeller in the outdrive was replaced again just to make sure in case the other one (which was intact) was defective. the water punp driven by belt was replace and flushed. The new risers were taken out and re-check if by chance some blockage got in there. The hoses were re-checked for blockage. Nothing!! They engine was flushed with clean water..not much stuff came out. Tsat checked. Now unlike before,it seems both risers are getting hot, where before only the starboard was hot. The Blockage moved?? The mechanic thinks it maybe in the Block? He mentioned pouring acid into the block and leave overnight..to remove the blockage? Has anyone done this? is it safe? thanks"
 
"Ray;
Are you running the dri

"Ray;
Are you running the drive impeller water to a belt driven pump and then to the T'stat housing? Or do you mean the water circulation pump when you say "the water pump driven by belt was replace and flushed."?

It sounds like you need to do a flow test.
Disconect the water incoming hose from the T'stat housing and run it into a bucket while someone else starts it and idles at 1000 Rpm.
A V-8 Alpha pump should pump about 5 Gpm; so a standard plastic garden bucket should fill in less than 1/2 minute.
If not, something is wrong.
Only run engine briefly for this test, as it won't be getting any water at all, and the manifolds and risers will heat up very quickly.

Rod"
 
"I had similar problems with m

"I had similar problems with my 98 5.0L alpha1 Gen2
after replacing the manifolds, spacers, risers, and circulating pump and still having similar problems that you state I started looking again and eventually found the metal plate from the flapper (the rubber melted off) jammed inside the upper housing in my outdrive, it was wedged against the shift shaft. It made it through the y-pipe and the exhaust bellows!
Good luck"
 
Mike;
Whenever a flapper valv

Mike;
Whenever a flapper valve mysteriously goes "missing" you can be sure it will be lodged somewhere in the Y pipe or the drive. Sounds like you got lucky in that it made its way into the drive. This is much easier than fishing it out of the Y pipe.
 
"Hi.This is interesting! I wou

"Hi.This is interesting! I would appreciate if it could be explained what causes this backwood draw of water and exhaust gases toward the riser. I have a 300 stern drive leg which has the flap just above the main lift foil. When i stop my motor i attempt to have it running at idle for at least one minute, even longer on a hard or long run. Would appreciate hearing if this has happened to any 300 stern drive leg owners and how they resolved the problem. Jon"
 
"Please note my spelling of Ba

"Please note my spelling of Backwood should be Backward. It is winter here, not as cold as it can get in the USA.I do not have to prepare my boat for winter. Jon"
 
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