manifold & riser

[memaw777]

I have 1978 Century 23' 350 260 hp Ive been reading on here about manifolds getting hot. are'nt they supposed to my riser gets to hot to touch.

 

[Don S]

Re: manifold & riser

They should never get too hot to touch. They will get pretty warm while running, but just at the dock they should be almost cold. If not the impeller could be bad or you could have plugged manifolds and risers.

 

[memaw777]

Re: manifold & riser

so if i need to replace manifolds whats the best. if there plugged would this cause motor to run hot it stays at 150 when running but goes up to180 when i stopand idle

 

[Don S]

Re: manifold & riser

If it's only 150 when running, the manifolds and risers are probably not the problem, what about the impeller???? How old is it?<br />And what kind of engine and drive do you have??

 

[memaw777]

Re: manifold & riser

Its a Rebuild from jasper mercruiser 260 350 engine. Outdrive 1 year old. How hot should the riser get. Maybe I dont have a problem but Ive never seen the riser cold even when idle

 

[memaw777]

Re: manifold & riser

Are Moore exhaust manifolds the way to go if I need to replace

 

[KaGee]

Re: manifold & riser

Originally posted by memaw777:<br /> Are Moore exhaust manifolds the way to go if I need to replace

IMHO, the Moore (GLM) manifolds seem like a viable alternative to the existing OEM and aftermarket products. They are definetly less money. GLM has a good reputation. Supposedly, the one's you are looking at provide for better performance.<br />Stay away from the aluminum ones if you are on salt ot brackish water.

 

[memaw777]

Re: manifold & riser

what about Osco manfolds

 

[Don S]

Re: manifold & riser

What about the impeller?????<br />All the manifolds and risers in the world will not cure a bad impeller. And all it would take is a plastic bag over the intake and the pump runs dry for a few minutes to loose a blade or two. Then you could have cooling at speed, but not at idle because of the reduced flow.

 

[memaw777]

Re: manifold & riser

impellor is good

 

[Scaaty]

Re: manifold & riser

Originally posted by memaw777:<br /> impellor is good

Like Don said..only don't look at it..REPLACE it. Then try it again. Got a seawater strainer? Check it. When is the last time the circulation pump was checked? I can rest my hands on my manifolds when running. And as you say its a 1978, when was the last time they were changed? Saltwater will have them junk in a few seasons

 

[dygrp]

Re: manifold & riser

is the risers another name for exhaust elbow and does the water that goes into the exhaust manifold go thru that elbow and out the prop on a standard cooling system?

 

[tommays]

Re: manifold & riser

NO the riser is a piece that fits between the manifold and the elbow and rasies the elbow higher so that the ellbow is the correct hight above the water line of the boat <br /><br />if the ellbow is to low water will get into the motor frow waves of someone standing on the stern of the boat.<br /><br />tommays