Omc exhaust manifold temp. high

[ulster]

OMC Twin 4.3's starboard manifold runs cool to the touch at just over 3000rpm<br />port runs hot? same RPM not hot enought to burn your hand but hot enough so you can not keep your hand on it?<br />Both motor T stat housings feel the same and the gauges indicate the motors are being cooled OK but I am concerned re the exhaust temp.<br />Cooling lines to the manifolds are cold to the touch (Same on both motors)<br />When idled to 900rpm exhaust cools down Ok is this a problem?

 

[Don S]

Re: Omc exhaust manifold temp. high

When was the last time the impellers were replaced?<br />If they both have new impellers, I would be looking at manifolds and risers plugging up. How old are they?

 

[ulster]

Re: Omc exhaust manifold temp. high

This is my 3rd season with this boat (With no problems) I do not know when the impellers were replaced or how old the manifolds are?<br />How do I know if the manifolds and risers are plugging up is there a way to diagnose this <br />The boat is an 86.<br />I am leaning towards changing the impellers.

 

[Don S]

Re: Omc exhaust manifold temp. high

Yes, the impellers are due for replacement.<br /><br />Pull the risers and look at them. If they are plugged, it will be obvious.<br />If you aren't sure, there are marine mechancics all around the world that know what they are looking at. Just take them in and ask.

 

[ulster]

Re: Omc exhaust manifold temp. high

Should the risers be cool to the touch?

 

[KaGee]

Re: Omc exhaust manifold temp. high

Originally posted by ulster:<br /> Should the risers be cool to the touch?

Warm... should be able to let your hand rest there for a moment without discomfort.

 

[whywhyzed]

Re: Omc exhaust manifold temp. high

Just checked my OMC 3.8 -After a hard run, they are about 100 degrees F. Left and right the same. My Engine runs 170ish.