Hot Stbd Riser

OK, I'll get that tonight.

Another question, the poppit balls in the tee on the t-stat housing, they just seem to lightly sit there, there are springs on them, but they seem to be loose. How are these supposed to be adjusted?
 
There is no adjustment for the tee fitting with check balls. They are replacement items. Debris not caught by the strainer can block a valve pushing more water in one direction. This happens a lot with salt water boats.


If you get a chance tonight, please check the water flow feeding both riser/elbows hoses. What would be ideal is to connect a hose that you can put into a bucket for 10 seconds (no longer) and compare port to starboard how much water goes into bucket during that period. That should resolve if there is a water flow difference.

-John
 
John, thanks for all the input so far... keep it coming... VERY much appreciated!

I went down tonight for just a few...

I pulled the t-stat housing off and disconnected the 6 hoses to it.

The 2 hoses on the stbd side, the inlet to the riser and inlet to the manifold... I put the garden hose to riser hose and water flows easily and comes out the hose from the manifold. Reversed the process with the same results.

Now I do the same thing on the port side and can get the hoses to swell from the water pressure and flow, HOWEVER, no flow out of the manifold hose, reverse the process again and have the same result.

Now... Is there something wrong with the stbd riser?????

I have to re-tract my statement about swapping the risers. That was not done. I just found out my son handed them back to me from the same side they were removed from.
 
How about swapping it (manifold) out with the one you just pulled off?
 
I have another manifold for the port side. Just didn't get around to putting it on yet. Was more focused on the hot issue with the stbd side.
 
I can understand that. Did you notice this out of the blue or did something make you think the boat was running hot? Did you change spark plugs recently - I ask because another tell tale sign of head gasket failure might be "White" spark plug tips, but usually that condition goes hand-in-hand with steam.
Anyway - good luck getting to the bottom of this.

FWIW - my boat is a big block RWC, but my risers are very warm to touch. Both are about the same and my temp runs at 175 deg.
 
This was not an issue last year.

Last month when I launched, and even running in the driveway, the temp gauge was reading a bit higher. Didn't think much of it. After we launched and went for a quick run, the temp started to climb. I lifted the hatch and felt the risers. This is what I'm chasing.

There is another 5.7 next to me and a 4.3 on the other side. Both of their risers are cool to the touch, same as the port one on mine.
 
I am suspicious of a kinked hose going to the port riser. Have you checked for this possibility?

You say from your post that on the port side, you cannot get water to flow either way through the hoses and manifold/riser. You also imply that no water would flow into the hoses either way. I really would question this last item. If no water can flow into the manifold hose, then you could never get any cooling water flowing through the manifold, and I think it would get very hot. I suspect you did have some flow from the manifold hose out the exhaust outlet, just none back towards the thermostat housing.

From what you describe, you have proper water flowing up through both manifolds, as both seem OK for temperature. Water flows up through the manifolds from the thermostat housing when the engine comes up to temperature and the thermostat opens. TThe water from the manifold has to flow up through the riser to mix into the exhaust. So to me this implies the riser itself is not obstructed, and you don't accidentally have a 'block off' gasket installed there.

Before the thermostat opens, all water from the seawater pump should flow from the thermostat housing to the risers and out. If one of the hoses from the thermostat housing to a riser is blocked/obstructed, or the inlet to the riser is obstructed, then all the water from the seawater pump has to flow out the other side. So the blocked side would get hotter than normal, and the other side would be cooler than normal, as it has nearly twice its normal flow.

After the thermostat opens, and especially in cold water, much of the water from the seawater pump will still not flow through the thermostat, but will be bypassed in the thermostat housing to the riser inlet hoses. If one of these is obstructed, or the hose blocked, then you will have more back pressure for the seawater pump to work against. MAYBE this could cause the engine to run hotter than normal.
 
Can you send me your engine #? I want to check the gasket and tstat configuration.

BTW we are collectively close to solving this based on the diagnostics you have done. Both sides of the engine need to behave the same way. Most work in the way Dave described where raw water flows between the riser and the manifold. Some units separate the the riser from the manifold by means of a block off gasket (usually for fresh water cooling but several designs were used for raw water).

Before I have you pull the risers so we can finally solve this ...send me the engine number. Sorry it took a little while to get back to you....I was in Atlanta yesterday.

-John
 
OC873450 Engine Number

If water is fed into the riser, I don't think it should come out the manifold... Or water fed into the manifold, should not come out the riser inlet.

Both should discharge out the exhaust side, correct?
 
The water passage in the exhaust manifold lines up with the water passage in the riser/elbow. The hose connections go into these water passages, with no valves. So if you bolt them together without a gasket, they form a common water passage. Water that goes in one hole can come out any other hole, including the one that dumps into the exhaust.

The gasket that is used determines whether water can flow between the manifold and the riser or not. The situation I described above is what is common on a raw water cooling system, and the gasket has slots in it, so the passages in the manifold and the riser/elbow are a common passage.

What John is saying is that there were some raw water systems produced where a block off gasket was used, so they would not be a common passage. In that case, water into the manifold should not come out the riser. So he is checking the S/N to see if that is the case for your boat.

There is normally a block off gasket used in a fresh water system, so that on each side fresh water circulates through the manifold (therefore and inlet and outlet hose on each manifold), and raw water goes out through the riser/elbow (the third hose).

If you have the case of a block off gasket used with RWC, then I think you should have three hoses to each side, not two. You have to have a warm water hose to and from the manifold, and a cold water hose to the riser.

Let's see what John comes up with.
 
All the parts I have bought, have been in line with parts diagrams that I have found on www.stemtostern.com and www.ebasicpower.com I cross reference between the 2 to make sure.

I have raw water cooling. The pump is in the outdrive. The gaskets between the manifold and riser are the restrictor gaskets. The slots are on the port and stbd side, while the fore and aft are a solid gasket with the small 1/8" hole.
 
Those are the same gaskets that are in mine....good luck with this situation.
 
Just so you know what I did. I took your engine number and put it into:

http://www.mercurypartsexpress.com/PartsExpress/HomePage/homepage.asp

This site gives you all the oem parts associated directly with your engine. What I was looking at and would like you to confirm is the cooling system configuration and the exhaust manifold riser configuration.

At the end of the day, what Dave said is accurate. I expect that you have one hose that feeds each manifold and another that feeds the riser/elbow on each side. Both sides should behave the same way. If you push water into the riser/elbow fitting it should come out the manifold fitting. Which hoses go where is important. I have seen people hook up the wrong hoses from the tstat to fittings and have heat issues. Also, I don't believe your engine has "risers" on it. Risers sit between the manifold and elbow to raise the height of the exhaust. Risers are also a source of improper gasket problems.

So, the port side flow between the elbow and the manifold appears blocked. That is consistent with the low temp reported on the IR temp on the elbow. Cooler water is not mixing with the manifold which is why the temp is 110*. The port manifold is getting way hotter than the IR gun recorded.

So, what I would like you to do is pull the port elbow and check it. If forced water flows through it unrestricted from both ends, then it is ok.

The next step is to pull the port manifold. The reason why is if I have you put water to it's lower fitting, it will flood down the exhaust port and screw up your engine. My guess is that the port manifold is blocked and needs to be replaced.

Let me know.

-John
 
OK, so what you are saying is that water fed into the elbow inlet, should flow out of the manifold inlet? And water fed into the manifold inlet should flow out of the elbow inlet. The side that is doing this is the stbd side which is getting hot.

I am doing this with the hoses pulled from the t-stat housing.


The port side, when water is fed into the elbow inlet, it does not flow from the manifold inlet, and water fed into the manilfold inlet, does not flow from the elbow inlet.

Did I just confuse everyone??? :smt021 :lol:
 
Nope. The problem is on the port side. You are being tricked by the low temp on the port elbow. The temp difference on the starboard side is much closer to what a normal engine operates at.

-John
 
John, YOU ARE THE MAN!!!!!! The port manifold was rusted shut at the intake on the bottom...

New manifolds are in, fired it up and it now runs the same temp on both sides...

Send me a PM with your address, I OWE YOU!!!!!!


OK, now I have a new problem... :smt021 The intake manifold had water lying on it from the various hoses... I have bubbling from the the right hand side on the manifold below the carb... :smt021

I hope they are easy to change... getting tired... :smt101
 
Glad I could help. Can you post a digital photo of what you are seeing?

-John
 
Yeah, if I remember the camera... the intake manifold has rust, and it looks like there are a few pin holes with air escaping.

I'll also try to take a pic of the exhaust manifold inlet also..
 
Ow! Ow! Ow!

If I was you. . I would consider replacing both manifolds and both risers, and getting a fresh start!
 
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