Mystery to be solved - reward to whoever gets it!

[JustJason]

Re: Mystery to be solved - reward to whoever gets it!

Do this,

Disconnect the main water line into the tstat housing and put it in a 2 gallon bucket. Start the engine and run at 1000rpms for 15 seconds then remove the water line from the bucket and shut the engine down.

How much water did you get? Measure it out in quarts.

 

[smokeonthewater]

Re: Mystery to be solved - reward to whoever gets it!

well what's the deal? swap out the gaskets yet?

 

[[OBC]Patch]

Re: Mystery to be solved - reward to whoever gets it!

Your head is clogged on the affected side. you just need a new head gasket, probably.

 

[kend301]

Re: Mystery to be solved - reward to whoever gets it!

I really stick to giving advice only on Sport Jets as it is what I know But since there is no solution here I am just wondering if the problem is the reverse of what everyone is looking at . Could it be that the cool side is staying to cool and not coming up to temp and forcing the other side to absorb more heat thus running hotter ? I have no idea how to solve this just wanted to shed some light on a different approach . You posted temps of 101 and 160 , what are they supposed to be? If it is 125 or so the cool side could indeed be the problem side .

 

[c0y0te56]

Re: Mystery to be solved - reward to whoever gets it!

Hi KWG
Not to beat a dead horse, But didn't you say you didn't have this problem till you changed over from the restrictor gaskets? (post #25)
I had the same problem and doing that solved it.
Good Luck
JT

 

[smokeonthewater]

Re: Mystery to be solved - reward to whoever gets it!

I guess ole' KWG is gonna be one of those guys that gets his answer and just disapears......... oh well

 

[BAproject]

Re: Mystery to be solved - reward to whoever gets it!

Sounds like you stole my engine, as I am having the same exact problem (temps may vary a bit and my engine is smaller hahaha).

I have gone thru the same steps as you and am also a bit puzzled.

I've come to the conclusion hat there is a blockage in the engine itself. You may not have enough flow coming back up thru the intake manifold. This could be caused by several different things, blockage in the engine from debris, corrosion in the ports on the cylinder heads, a combo of both????

I started my engine with the top off the t-stat housing so I could observe, Not the safest thing to do so beware, as the t-sat can shoot out! I was surprised at how little water flow there was coming through the t-stat (which is new and functions correctly) when it came up to temp.

So I put the thing back together the correct way and pulled the drain plugs in both sides fo the engine, fired it up and found that there was not a lot of water flow pushing out of these drain holes.

My next step is to pull the heads and go from there....good luck man! I feel your pain

 

[smokeonthewater]

Re: Mystery to be solved - reward to whoever gets it!

lol all 16 of his posts were made in 4 days.... now nothing in 10 more

I'd really like to see him post up again but I suspect that he changed the gaskets and it worked so now he's gone....

 

[BAproject]

Re: Mystery to be solved - reward to whoever gets it!

Right?! I'd like to know what he found

 

[KWG]

Re: Mystery to be solved - reward to whoever gets it!

OK, I'm back.

The reason I haven't been back on here in a while is kind of embarrassing but I will share it with you in hopes that maybe someone else will learn from my stupid mistake.

I performed a water jacket pressure test and found there were cracks in both heads in the exhaust facings. I had replaced the original heads in 2006 with these 'remanufactured" heads. The remanufacturing process involved welding cracks in those very spots and they had let go. So I tore it down to the short block and bought NEW heads with supposedly a heavier casting and installed these heads. The original heads cracked whe I ran through some mud and clogged the cooloing system. All of which I thought was cleared out.
When I had the heads off I checked real good and there was about an inch deep mud that had hardened at the bottom of the water jacket around the cylinder walls! Ah ha, I thought at last I had found the problem with the uneven heat. So I painstakingly cleaned all of it out. Then put on the new heads. Got everything back together and the engine ran better than new ...really...better than new.

But, (theres always a "but") the uneven temp. problem still exists.
And I am still stumped. That's why I've been away so long. I would do a followup if I had found the problem!

I replaced the water tube hose between the drive bell housing and transom because it was too long and kinking some and I started running engine at little higher rpms while on the muffs and that seemed to work OK until yesterday when I was running it at 1300 rpms on the muffs and checking the riser temps. (Updates Merc bulletin states to run at higher rpms on muffs)
All of a sudden the temp reading drops out at the gauge! Telling me water was not going past the temp sensor. I cut the engine. Let sit for 30 seconds restart and gauge comes right back up and I throttle down to 1000 rpms and temp gauge holds like a rock there at 160. No problem. No milkshake thank God.
There must have been more being pumped out than was comming in is all I can think of.
Engine still purrs like new. Starboard manifold 159, Port 109!

Please don't say it's normal for starboard to run a little higher ... this isn't a "little higher" this is a "lot higher".

I used some short sections of clear hose and swapped feeds at the tsat housing to the manifolds and that seemed to help keep the temp down closer to port side but it still was about 15-20 degrees higher. I also could see lots of big bubbles comming out of the tsat housing going towards the manifolds. Should this have bubbles or be solid flow?
Also at the outlets at the transom plate it was still is a larger flow going out the port exhaust. This would logically tell you there is a restriction on the starboard side somewhere ...but as I've said all the manifold/risers/elbows are clear ... checked and flappers are like new ...no blockage down in the Y pipe.

I did a volume test of the seawater pump, manual says to have it in the water and not on the muffs so I put the drive in a large tub (this seems to solve the gauge dropout thing as now it can keep up with the circulating pump evidently) ... anyway, ran it up to 1000 rpms and pulled the input hose at the tstat housing and shot the water into a bucket for 15 seconds.

My drive is a 1.65:1 gear ratio and the Merc chart says it should have put out 3.6 qts. MINIMUM ... mine was 4.5 qts. ... so that eliminates that.

I have run out of things to check. I really have.

Things that have been checked:

- All exhaust manifolds/risers/elbows are either clear as a bell or new.
- Water input test shows plenty of flow
- Tstat new
- All hoses clear (checked visually)
- Block water jacket cleaned out while heads were off
- Block water jacket pressure tested OK
- new circulating pump
- tstat housing visually checked clear (however I would like to compare it side by side to a new housing to make sure nothing has worn away that I can't see)

So what could it be?

Looks like I am back to square 1 (although the engine now runs sweeter than ever if I can just get this cooling issue fixed.) and it's driving me crazy.

It seems to stem from the manifolds not getting adequate water flow. When the manifold hoses go back to their normal positions on the tstat housing the starboard manifold gets real hot and port stays cool ... measurements at the elbows are S-159 P-109 and their respective manifolds at this point are S-160 and P-120. When I swap hoses at the tstat housing it gets better ... but both sides stay within 15-20 degrees of one another (which I hear IS normal for Mercs.) and both exhaust manifolds are in the 120-125 range. So what is going on here? I am sure stumped.

ANY thoughts/help is greatly appreciated.

Kirk

 

[KWG]

Re: Mystery to be solved - reward to whoever gets it!

BTW my next grasp at a straw will be to change to restrictor gaskets I guess and see what happens.

 

[JustJason]

Re: Mystery to be solved - reward to whoever gets it!

You shouldn't have any bubbles at all the pump's inlet screens are below the water line.

 

[ewkearns]

Re: Mystery to be solved - reward to whoever gets it!

Hello guys, I am new to this forum.

I can take a C-clamp and clamp off the port supply hose at the Tstat housing and the water will then pour out the starboard side and spit at the port. The starboard manifolds, risers and elbows then run cooler than the port! All the while the engine temp. stays rock solid at 165! AND when I then remove the C-clamp (with the engine still running) the heavy stream REMAINS on the starboard side!!?!
(you would think it would go back to the other side like it was before the test began)
If I shut the engine off and let it sit a while then restart it then again starts with full flow out of port.

To me, this sounds like insufficient supply of cooling water from the pump. What flow there is, is taking the path of least resistance and it isn't enough to keep everything full of water.

 

[KWG]

Re: Mystery to be solved - reward to whoever gets it!

Did you see the part about me doing a volume test?
Seawater pump bringing in 4.5 qts. every 15 seconds at 1000 rpms.
My drive should be 3.6qts Minimum ...so I'm good there.
Thanks

 

[CLAYAROBINSON]

Re: Mystery to be solved - reward to whoever gets it!

If switching gaskets doesn't work. Have you tried replacing the engine yet? I think that might solve the problem. How much of a reward do I get if this works?

 

[JustJason]

Re: Mystery to be solved - reward to whoever gets it!

I wouldn't bother with gaskets until you get the bubble issue fixed. Fix what you find first instead of jumping around. Plumb in some clear line on the same main water line that goes to the tstat and see if air is present in that. IF it is, then it's downstream back towards the drive. Water pocket cover seal inside of the upper section of the drive is a likely culprit.

 

[KWG]

Re: Mystery to be solved - reward to whoever gets it!

This is an Alpha 1 gen 2 ...I don't think it has a water pocket seal.. also the tub of water it is sitting in only comes up to the seam between the 2 halfs of the drive and althogh the intake screens are below the waterline the actual pump is still above ...I wonder it that amy be causing the bubbles?
I will plumb a clear hose on that one too and check it out ...could be when it sits down in the water there would be no bubbles.
Thanks, going to get some clear hose.
Kirk

 

[Don S]

Re: Mystery to be solved - reward to whoever gets it!

While there may not be a water pocket in the Gen II drives, there is still a tube with a seak, if that seal is damaged or the tube has a hole in it, it will suck air.

 

[Adirondack]

Re: Mystery to be solved - reward to whoever gets it!

Told my wife to sit in the center of the boat. Got rid of the 30 degree starboard list. Problem solved.

 

[KWG]

Re: Mystery to be solved - reward to whoever gets it!

Don S is right,

The tube has O rings on the inside and they are fairly new (I thought)
If I see air bubbles comming in I will look at going back in there and check those O rings.