1973 Merc 850 Exhaust

[ShowMeGuy]

I have a 73 Merc 850 that has 2 opening sunder the bottom cowl. I believe it's call the exhaust extension plate?

How much was should be coming out from those ports if any? This is where I'm leading into my next question, the Motor runs/idles out great when its first put in, shifts in and out of gear without stalling out etc. But if I get it warmed up it doesn't want to idle so good and wants to stall out when engaging into gear.

How is a good way to test to see if water is getting into the cylinders???

Ted

 

[Texasmark]

Re: 1973 Merc 850 Exhaust

Exhaust relief and it is common to have water coming out; maybe a mist, maybe none, maybe more. I had a Johnson 125 that I used to ski behind and at idle you couldn't see anything but exhaust. When I was up and going, both ports had solid water coming out of them.

Water in a cylinder will polish it nice and clean and brite.

Mark

 

[Chris1956]

Re: 1973 Merc 850 Exhaust

Yes, those square holes are for exhaust relief. Some water may come out of them, especially at high speed and idle.

Water intrusion will usually clean up the spark plug, so it looks steam cleaned.

 

[Texasmark]

Re: 1973 Merc 850 Exhaust

Water intrusion will usually clean up the spark plug, so it looks steam cleaned.

Cleans the piston crown too.

 

[ShowMeGuy]

Re: 1973 Merc 850 Exhaust

Exhaust relief and it is common to have water coming out; maybe a mist, maybe none, maybe more. I had a Johnson 125 that I used to ski behind and at idle you couldn't see anything but exhaust. When I was up and going, both ports had solid water coming out of them.

Water in a cylinder will polish it nice and clean and brite.

10-4

Mark

Yes, those square holes are for exhaust relief. Some water may come out of them, especially at high speed and idle.

Water intrusion will usually clean up the spark plug, so it looks steam cleaned.

10-4. Ok guys, take a look at my plugs. The bottom 2 look a little bit different than the top 2. Esp the 4th one. Should I be getting gaskets and seals and pulling Powerhead and investigating?
Left to right. 1 - 4 Top - Bottom.

Thanks! SMG@!

 

[Chris1956]

Re: 1973 Merc 850 Exhaust

Hard to see the plugs clearly, but all look like that have some dirt on them. So I do not see any signs of water intrusion. Did they have water drops on them? Any rust?

#4 looks a little pitted. could that be from water?

 

[ShowMeGuy]

Re: 1973 Merc 850 Exhaust

Hard to see the plugs clearly, but all look like that have some dirt on them. So I do not see any signs of water intrusion. Did they have water drops on them? Any rust?

#4 looks a little pitted. could that be from water?

No rust on them but something looked a little off with the #4 I thought as well. I bead blasted them and will install them and re-run from a known baseline I guess.....