Impeller is changed but still getting hot on the driver side manifold of my 5.0l merc

[bamafutbal]

i am the one that had the burnt wires a couple of months ago, they were laying across the driver side manifold, engine temp showed around 190 but driver side manifold was very hot, passenger side was warm. anyway, had the impeller kit put in but it did not change anything (impeller at 1.5years old looked great). water comes out of the passenger side but none on the driver side on the outdrive with muffs in place. i was told that it has or feels like there is water pressure on the hose going into the thermostat. i have forgotten/didn't understand most of the other stuff as he was going down a laundry list to check. the guy doing the change for me is certified outboard mechanic and very trust worthy but he was stumped as to why no water was not going all the way through. i do remember after turning engine off, he said he had water draining out of the bottom, underneath the manifold, he showed me a plastic screw and a little water coming out. he is checking with a buddy who works a a local i/o shop and get back hopefully on sunday. just wanting to kind of help out if anyone has an idea
boat is the 20 1/2 foot 1999 blue water with 5.0l merc

 

[achris]

Re: Impeller is changed but still getting hot on the driver side manifold of my 5.0l

First, could we have a serial number for your engine. Helps us locate the right drawings so we ain't talking about apples and you have pears, if you get my drift....

It's not unusual for the manifolds to run at different temperatures. As long as both are being cooled. Checking with the engine running on flushers is only a guide. What's happening when the engine is doing about 2000+rpm in the water?

On the flushers, you could remove the hoses from the bottom of the manifolds and check that you have water coming from both. If one is more than the other try just closing off the one with water and make sure water comes from the other. But don't run for too long without water running the manifolds, no more than a minute.

Chris............

 

[wil7483]

Re: Impeller is changed but still getting hot on the driver side manifold of my 5.0l

Sounds to me like you have a clogged manifold which is preventing the water from circulating on that side of the engine. Explains why the manifold is hot and explains why water is not coming out.

 

[sarantis]

Re: Impeller is changed but still getting hot on the driver side manifold of my 5.0l

i have similar problem.i made the mistake to change manifolds because all they say it's the most possible (gm 305).The last thing i've not checked because i've not the boat out of the water yet is the Y exhaust pipe.I strongly believe that the flap inside it is partially destroyed and prevents the proper water circulation.Don't foget to send us your results.

 

[bamafutbal]

Re: Impeller is changed but still getting hot on the driver side manifold of my 5.0l

engine serial number is OL080644
transom serial # ol294132
and another number is ol424823 with it being a alpha 1 gen 2
thanks
john

not sure if first is a "o" or zero

 

[Don S]

Re: Impeller is changed but still getting hot on the driver side manifold of my 5.0l

Pull the risers off and look at the water passages in the manifolds and risers. Also check the water outlet on the riser (covered with the hose).
If they are plugged up, it's from corrosion from the inside of the water passages in the manifolds and risers.
Overheat is usually the first indication you need new risers or manifolds. after that you get water in your engine. If it's salt water, you loose your engine.
If the passages are plugged, change both manifolds and risers. DO NOT try cleaning.