Logo
FULL SITE MENU

43 lx exhaust temps

M

mike1970

Member
"I have a 1996 merc 4.3lx v-6.

"I have a 1996 merc 4.3lx v-6. New manifolds and risers last year. The starboard manifold & riser will get hot to the touch. The port side is perfect- cool to warm. When testing it out of the water, on the hose, I will get steam and little water flow exiting the stbd side. Port is fine- lots of water and cool.However some times it is fine- good flow from both sides.When it is getting hot, I will block off water flow to the port side and then will get good water flow exiting from the stbd side.
I have removed both hoses going to the manifolds and am getting the same good flow to both sides,however the stbd side will get hot.seems like the water is getting blocked somehow.
Possible blocked riser?? Even though they are new?
Any ideas will be greatly appreciated!"
 
"Ayuh,....

The risers are [

"Ayuh,....

The risers are Never the Same temps,....
And,..
It's usually the starboard side that's warmer..."
 
"Thanks, Bondo. I know that th

"Thanks, Bondo. I know that the risers are never the same temp, however in my case, the stbd becomes hot, you can't even touch it, as well as there is no flow of water out of that side, that is what has me baffled, because the port side is perfect, nice and cool, as well as plenty of water flow."
 
"Mike,
Why were the manifolds

"Mike,
Why were the manifolds and risers replaced? Was it because of the same problem? If not, did this problem develope immediately after they were replaced?"
 
"Mike;
If I was you I would f

"Mike;
If I was you I would flush each manifold riser separately and see if the flow is restricted in any way.
If you have a T fitting on top of the stat housing with separate hoses to each riser, check the ball restrictors at each outlet of the T fitting. The stbd side may be plugged or restricted.

A tester like this may help:
220742.jpg
Flush Attachment
 
"thanks for all the feedback.

"thanks for all the feedback. i just removed the riser and was wondering which gasket needs to be used. looking online i am getting 2 different ones. the first is from a mercruiser site that shows a gasket w/ 4 long, oval holes to let the water pass thru. i am only showing this one from mercruiser. the other is from all other sites that shows the gasket w/2 oval holes along w/2 small holes. it is called a restrictor gasket. they say that this is the one to use on all raw water cooled engines (which i have). the gasked that was installed on my motor was the one w/ the 4 oval holes.
Does this make a difference? I haven't pulled the other riser yet.
thanks,
mike"
 
"The restrictor gasket is used

"The restrictor gasket is used if you have secondary water hoses to the risers from a T fitting on the stat housing.
The full flow gaskets are used with engines where the water is fed to the base of the manifolds only.
Whichever is used, they should both be the same.

Rod"
 
"thanx Rod-
looks like the co

"thanx Rod-
looks like the correct gaskets are used.The risers are still like new- no restrictions. The exhaust shutters are working freely, and the exhaust pipe is clear- no restrictions.
I am still baffled."
 
"I'm with BT Doctur it sou

"I'm with BT Doctur it sounds like a weak impeller, it doesn't take much wear for these to not work as they should.
biggrin.gif
I had the same problem new impeller and all good."
 
Back
Top