Mercury 200 20 hp exhaust spray?

[tomhath]

Merc 200 20 HP SN 4585788 I bought last fall - indicator stream was weak, intermittent, and very hot. The impeller looked good but I found the remains of another impeller in the water pump and tube; kind of surprised that any water at all was getting through. Someone replaced an impeller that must have been completely torn apart without looking for the missing pieces...

After I cleaned the chunks of rubber out the stream is strong, steady, and barely warm. But I don't see any spray coming from the exhaust ports that are below the powerhead. I'm looking for a service manual, but in the mean time is there somewhere else I should check for a blockage? I assume there should be a light spray with the exhaust.

 

[Flipperboat]

Re: Mercury 200 20 hp exhaust spray?

I just separated my mid section from the powerhead and when I got the new powerhead gasket noticed that the area you are referring too is closed off from the powerhead. In fact the exhaust is through hub exhaust and that is why you do not see any spray. I have included some pics of what it looks like after the two pieces have been separated. Also I got a downloaded service manual off the internet and the only section not in the manual is the midsection???????




The first pic is looking at the underside of the powerhead note the square port. That is the exhaust port. The powerhead gasket is still on the powerhead so you can see it closes off the section that mates with the midsection.

Second pic is the mating part of the mid section that leads to the two ports. I haven't been able to figure out why they are even there unless its for racing features or open exhaust.

 

[Flipperboat]

Re: Mercury 200 20 hp exhaust spray?

Click on the pics to get a better view.

 

[tomhath]

Re: Mercury 200 20 hp exhaust spray?

Click on the pics to get a better view.

Thanks for the answer. I think that exhaust port is to lower the back pressure when starting; otherwise you'd be fighting the water pressure down at the prop.

 

[Faztbullet]

Re: Mercury 200 20 hp exhaust spray?

It is to relieve backpressure in water to help idle/starting , while you got it pulled go ahead and replace lower crank seals...