Closed Cooling System on Port Engine Running Hot(ter)

[tpenfield]

Interestingly enough . . . I was cleaning out the garage this weekend and came across a box of stuff that was from the boat when I bought it 4 years ago . . .

and found these



Makes me wonder if the PO was chasing some cooling problems :noidea:

 

[tpenfield]

UPDATE:

Now that I have the boat out of the water for the season, it is a lot easier to do diagnostic work. So, today, I took the inlet hose and the barb fitting off of the inside transom assembly to get a better check for 'Bravoitis'.

Here are a couple of pictures of the hose and insert that comes through the transom assembly, as well as the barb fitting.



It is showing early signs of Bravoitis. The area that is starting to crush is the upper portion, from about 10 o'clock to about 2 o'clock. When I did my borescope thing during the season, I was only able to see the lower portion of the insert, which is fine.

Here is the barb fitting, and it shows evidence that the mounting flange (or whatever you want to call it) is corroding.



So, it looks like I have that beginnings of Bravoitis, and I'm sure it will only get worse. I am not able to get the special insert remove/installation tool into the plastic insert, so it has reduced its diameter more than just a wee bit.

I did want to see if that much of a narrowing of the inlet plumbing would make a difference in the cooling. So, instead of using the ear muffs, I connected my bucket & hose combo directly to the intake hose that leads to the seawater pump.

A word about my earmuff/bucket setup . . .



I use this for winterization and also wanted to use it for this set of diagnostic work. The green hose exits the bottom of the bucket and goes to the earmuffs (normally). The black hose (garden hose) fills the bucket and I normally run the garden hose at full tilt so the bucket overflows. This setup provides a consistent amount of gravity feed to the outdrive (or sea water intake hose) rather than the pressure of the garden hose, so it takes any effect of the garden hose pressure out of the 'equation'.

Anyway, my initial run of the engines was with the bucket feeding the earmuffs at the outdrive. I got, per the helm gauges, Port 167 F and Starboard 148 F. This is after 20 minutes of running time from a cold start. Then, based on my discovery, I 'by-passed' the outdrive and the Bravoitis area and hooked the green hose directly to the sea water pump intake hose where it would normally connect to the barb fitting at the transom assembly.

I ran the Port engine again and let it come up to temperature. . . . pretty much the same 165-167 F. Then, since I have a sea water strainer, I connected another hose directly to the sea water pump . . . so now I was by-passing the outdrive and the strainer. Ran the engine again (15 minutes) and it settled in a about 165 F as before.

I also re-verified the temps that I took with the IR temp gun, and those were pretty consistent with what I had done earlier in the summer.

OVERALL STATUS:

I should fix the Bravoitis . . . . and do both drives.

I still need to de-scale the Starboard Heat Exchanger, even though that engine is running cooler.

I should try to flush the Port engine block using one of those cooling system flush products that Rick suggested.

I also have a new t-stat for the Starboard engine, since it has too much by-pass and is not allowing the engine to get up to temp while idling. So, I drilled 2 small holes in the flange of one of the t-stats that I found . . . tested it on the stove . . . begins to open at 160 F and is wide open at 170 F. That will go into the Starboard engine when I work on the H.E.

Any other thoughts ??? Ideas ??? Prayers ??? etc. ???

I just don't want to launch the boat next season and still have the problem.

 

[Fun Times]

Ted as mentioned before, your port engine is fine... It's your starboard engine that has issues running to cold....Fix your starboard engine + the early stages of Bravoitis on both sides to be safe and go boating next year without any worry.

Happy winter to you.

 

[tpenfield]

Ted as mentioned before, your port engine is fine... It's your starboard engine that has issues running to cold....Fix your starboard engine + the early stages of Bravoitis on both sides to be safe and go boating next year without any worry.

Happy winter to you.

Thanks, Fun Times . . . Today, I am going to tackle the Starboard engine. . . will replace the T-Stat and de-scale the H.E. so I am 'apples-to-apples' on both engines. I just want to make sure I chase any remaining gremlins out of the Port engine . . . it may just be the Bravoitis.

I forgot to bring with me the laptop that has the Diacom software, (Windows laptop) so that will be next weekend. I'd like to re-run the tests with both engines idling at the same temperature per the ECM, etc.

 

[tpenfield]

Also wondering about the Motorcraft VC-9 iron cleaning of the cooling system that Rick recommended. I understand that oxalic acid (wood bleach) can do the same sort of thing. :noidea:

I have found a few posts on car restoration sites about using oxalic acid to bring back the cooling properties to older engines/cooling systems. It may be the thing to do considering the engines were 16 years old (740 hours fresh water, Lake Winnipesaukee) when I added the closed cooling to them

Thoughts?

 

[achris]

My thoughts? It's like chicken soup. "It can't hurt".....

 

[tpenfield]

My thoughts? It's like chicken soup. "It can't hurt".....

I like that . . . I'm still working on the Starboard engine . . . Basically have to 'undress' the closed cooling system to get at the thermostat. I wish the design of the SJE system was not so tight

 

[alldodge]

Does appear to have started bravoits but IMO I think it will be some time before it becomes a real problem. Have also found the after the plastic fitting has been installed for a few years in the hose, you won't be able to get the tool back in it. Replacing with new and the thin wall plastic pipe is the way to go.

 

[tpenfield]

Does appear to have started bravoits but IMO I think it will be some time before it becomes a real problem. Have also found the after the plastic fitting has been installed for a few years in the hose, you won't be able to get the tool back in it. Replacing with new and the thin wall plastic pipe is the way to go.

Not sure what you are referring to when you say "thin wall plastic pipe". I have see a retrofit for Bravoitis that uses a stainless steel adapter, but not a plastic pipe.

 

[alldodge]

Not sure what you are referring to when you say "thin wall plastic pipe". I have see a retrofit for Bravoitis that uses a stainless steel adapter, but not a plastic pipe.

The Merc kit is plastic. Here is the kit I used when redoing my Rinker
http://forums.iboats.com/forum/engi...ard-engines-outdrives/10246284-bravo-itis-fix

 

[tpenfield]

Starboard Engine Update:

I checked the starboard engine heat exchanger, and it needed a bit of TLC, similar to what I found on the port engine. Here are a few pictures, about 6-8 holes blocked on each end of the H.E.

This end, maybe 12-14 holes blocked . . .



So, I cleaned the ends and probed the holes with a wire, then did the 'Kaboom' treatment to the ends and the entire H.E.

I also put the new thermostat in . . . This one has 2 small by-pass holes, rather than the 3 large holes that the prior T-stat had. The larger/more holes are causing the engine to run too cool at idle and no load. (once the engine has load, the temp goes up into the 155-165 range on this engine)

Here are the 'old' & 'new' t-stats.



To get to the thermostat housing, you pretty much have to take things apart . . . takes about 1 hour to do all this.


I put everything back together and ran the engines in hopes of seeing the temperature on the starboard engine go up to the desired 160 F range at idle, as does the port engine. After a few minutes of running, the temperature (per the helm gauge) was coming up nicely. I took a look at the engine and could see coolant dripping down the engine block . . . . . . It was leaking around the thermostat housing gasket . . . looks like I did not get the new t-stat properly seated :facepalm:

Oh, I hate it when I do stuff like that . . .

So, I called it quits for the day . . . it was raining pretty hard anyway . . . outer rain bands for the hurricane (Matthew). So, I worked on my Mercury outboard, instead. I'll take another run at the Mercruisers this week. got to tear the cooling system down again and see what is going on with the thermostat housing/gasket.

The Admiral picked up a couple tubs of 'Wood Bleach' which is 95% oxalic acid . . . so, I will drain down the coolant on both engines and do the iron cleaning thing as well. Just trying to cover all the bases during the off season.

I am also wondering if there is a way to simulate the engines under load, while it is up on the blocks for the winter . . . maybe a big feeding trough or something, so I can put the engines in gear and have some sort of a load, etc. :noidea:

 

[tpenfield]

The Merc kit is plastic. Here is the kit I used when redoing my Rinker
http://forums.iboats.com/forum/engi...ard-engines-outdrives/10246284-bravo-itis-fix

Great, and thank you. I am assuming that even with these retrofit kits (SS or plastic) the corrosion may re-occur, but the tube portion is strong enough to avoid the crushing effect that dooms the rubber hose/insert ?

 

[alldodge]

Great, and thank you. I am assuming that even with these retrofit kits (SS or plastic) the corrosion may re-occur, but the tube portion is strong enough to avoid the crushing effect that dooms the rubber hose/insert ?

This is my understanding. The only pressure on the tube is just from compressing the bushing on each side of the rib

 

[Fun Times]

I also put the new thermostat in . . . This one has 2 small by-pass holes, rather than the 3 large holes that the prior T-stat had. The larger/more holes are causing the engine to run too cool at idle and no load. (once the engine has load, the temp goes up into the 155-165 range on this engine)

Just so you're aware, it seems earlier in the topic you put 3 holes in the thermostat vs the 2 you just did for the starboard side.
Here is the new thermostat with 3 smaller by-pass holes

http://forums.iboats.com/filedata/fetch?id=10216433&d=1467389933

I am also wondering if there is a way to simulate the engines under load, while it is up on the blocks for the winter . . . maybe a big feeding trough or something, so I can put the engines in gear and have some sort of a load, etc. :noidea:

Without a prop shaft dyno about the only other way to put a load on the engine would be to put the drive in a controlled pool of water such as truck loading dock/ramp full of water. If you just filled a tub of water like a horse water trough with the prop installed, the very first revolution of the prop the water level will be nearly empty...< Kind of fun to watch actually.
Below is just an example for an idea is all,

 

[achris]

When we had our shop I had a test tank built for bigger outboards and stern drives. That was a 2000 litre tank, with a lid, and a 350 v8 would empty it in under 3 seconds!

Chris.....

 

[tpenfield]

As far as the by-pass holes that I put in the T-stats, yes, there are 3 small holes in the t-stat on the port engine, and only 2 on the starboard engine. The 3 large holes was too much by-pass as evidenced by the starboard engine not coming up to temp. The smaller holes, whether 2 or 3 of them should allow the engine to come up to temp, and allow the t-stat to kick in.

The only purpose they provide is to give some cooling flow out to the exhaust manifolds during the several minutes it takes the engine block to come up to temp.

Without the by-pass, the coolant in the exhaust gets really hot before the t-stat kicks in and then the temp fluctuates wildly for a while until it can stabilize. It is really a preference on my part to dampen the temperature rise. The key thing is to not provide too much by-pass.

 

[tpenfield]

Without a prop shaft dyno about the only other way to put a load on the engine would be to put the drive in a controlled pool of water such as truck loading dock/ramp full of water. If you just filled a tub of water like a horse water trough with the prop installed, the very first revolution of the prop the water level will be nearly empty...< Kind of fun to watch actually.

You're right about the tub of water. . . My little 4.5 HP outboard can move a trough full of water pretty well. The Bravo 3 props will probably empty the trough on the first revolution. I'll just have to get the engines set up the best I can running on the hose. It is times like this is when I wish I had a trailer and could 'toss' the boat in the ocean for a quick test run

 

[HT32BSX115]

The only purpose they provide is to give some cooling flow out to the exhaust manifolds during the several minutes it takes the engine block to come up to temp.

Without the by-pass, the coolant in the exhaust gets really hot before the t-stat kicks in and then the temp fluctuates wildly for a while until it can stabilize. It is really a preference on my part to dampen the temperature rise. The key thing is to not provide too much by-pass.

Ted,

I think I have exactly the same San Juan systems you have. I am using the original stat provided with the kit. I never noticed if it had 2 or 3 (or even NO) holes in it. But my manifolds don't get very warm at all. (and it warms up pretty quick at idle)

Did you swap your stats to see if it would swap the problem?

 

[tpenfield]

Ted,

I think I have exactly the same San Juan systems you have. I am using the original stat provided with the kit. I never noticed if it had 2 or 3 (or even NO) holes in it. But my manifolds don't get very warm at all. (and it warms up pretty quick at idle)

Did you swap your stats to see if it would swap the problem?

I did put a new t-stat in at the beginning of the problems . . . it made no difference.

Yes, I'm pretty sure we have the same SJE system (MC324) I didn't like how the SJE system was acting when I first installed the kit. The engine temp would fluctuate wildly, rather than a smooth increase that you would normally expect. My t-stat modification (the holes) was my own creation to 'dampen' the system a bit. It has worked fine for 3 years. Starboard engine works fine, except the by-pass holes are/were too big and the engine tends to run a bit on the cool side because of it, as Fun Times noted.

Unless I find a 'smoking gun' when I take off the inlet hose that leads from the bell housing to the transom assembly, I am thinking that my problems have been a combination of the early Bravoitis along with the calcium buildup in the heat exchanger. I guess I got to plan on a calcium flush every year. I have not had to do much to the cooling system for the first 3 years of its use.

 

[tpenfield]

Quick Update:

I'm working on the boat today to see if I can get the leak at the thermostat housing resolved. When I took everything apart and was checking the mating surface of the housing to the intake manifold, I noticed that the surface was not completely flat and the t-stat housing could rock back & forth ever so slightly on its mating surface.

So, I checked the housing with a straight edge, and sure enough, the endpoints where the bolt holes are located are not flush with the rest of the housing surface. The picture below shows the high points after a bit of flat filing



So, I continued to file the surface down a bit to make it true.

I feel somewhat redeemed, in that it was not sloppy assembly, but the fact that the surfaces were not true. I'm not sure how the thing was holding tight for the past 4 years. :noidea: Maybe the gasket was just enough to make up the difference.

Anyway, I made a new gasket and put it all back together . . . but it is still leaking once I run the engine :facepalm:



This engine (starboard) is certainly having its way with me . . . starting to make the Port engine look good

I'm going to let the engine cool down and try doubling up on the gaskets . . . it would be so nice to get the engine temps in an 'apples-to-apples' condition, having them both run at idle in the 160 F temp range.