Interesting, last fall I decided to take my HE out basically because I had some overheating issues and the age of the boat I felt that it was time to have the HE serviced. After removing it I put it in the basement and brought it to the radiator repair shop in the spring. The shop called me and told me the two brackets were missing. I guess because I am getting older and forgetful I assumed they were on the boat and I just unbolted them. Well long story short they must of been brazed and had seperated. I could not find the bolts or the brackets anywhere.
I ended up fabricating new ones from aluminum scrap at the boat yard. Approximately1//8th thick by 2" wide and about 6" long. Made a distinct 90 degree bend (approx 11/2" and shaped the rest to the diameter of the HE. I used 1/4" thick rubber and taped to the bracket and used two other strips to go in the saddle shaped by the bell housing on the back of the engine and bolted it in place.
This turned out to be a very solid holding solution in that there is really no vibration. I believe the rubber has somewhat isolated the HE and thus has done away with another item that contributes to the noise level of the engine. The yard owner is a little skeptical of the aluminum and vibration but as I mentioned this appears to be quite solid....we will see what happens over the summer.

Gary
Sounds interesting, can you send photo(s)?

[QUOTE=hilbre;8819]I discovered that one of the HE brackets which is brazed onto the HE had come loose. To compound the problem, the other bracket, which must have been taking the full load had snapped in two. While I understand that the newer HE have a wrap around bracket I suggest that anyone with the older HE model pay close attention to this area when doing engine checks. Mine is out and at the shop for repair, naturally I am having it cleaned at the same time.
John Meyer
Hilbre 2135[/QUOTE]

Yes, I think this is a weak point on the older boats. When I removed my HE (on my 1998 boat, with some 600 motor hours at that time) to clean it, one of the brackets had come loose also. I had them both brazed back on and no problem since. I think it's just the brazing/welding job of the original manufacturer.

John - I would also like to see your solution. Some pix would be nice. Both of my HX brackets are also broken and it is basically vibrating in the air. I took 4 plastic tie wrap and fastened it. I think a strap with rubber underneath would be a very good solution.

When I bought my boat 3 years ago the engine had been replaced with a new M25XPB and had only 50 hours on it. Sometime the first summer, I noticed that both brackets that hold the heat exchanger on were broken. There doesn't appear to be anything to dampen the HE from engine vibration, so I suspect this is just a design flaw. I checked them a couple weeks ago and the new ones were still fine, but I won't be surprised to see them break again.

Last fall when I replaced all the coolant lines I had the HE rebuilt. The starboard bracket was totally separated, the weld failed. There was a thick rubber gasket behind it which I assumed is meant to help absorb vibration, it disintegrated when I took the HE off. I replaced it with another piece of rubber but I'm not sure it does any good, from the sound of it these things just break. Our engine had 1055 hours on it and I saw no indication that the HE had ever been off it before.

The HX seperating from the brackets is a very common problem. I have not heard of them breaking before. Maybe look at the hose routing, there may not be enough slack causing too much pressure on the HX/brackets. After mine seperated, I had them brazed back together and added a large hose clamp around the HX/bracket to hold it in place should the weld fail again.

I had this exact problem a few years ago and had posted just about the same info. One additional point.... if you replace the exchanger with the new brackets, make sure you get longer bolts to hold them in place. it is extremely annoying (if your on a mooring as I am) to have to make a couple of extra trips to the hardware store just for bolts.

Note this is not a great picture but a simple fix as in initial thread brackets that were missing and originally brazed to HE replaced with scrap aluminum and 1/4" rubber appars to be very solid fix.

My HE brackets recently failed and the rad shop said that the failure of those brackets is an intentionally engineered fail point.  The brackets are cold soldered on so in the event of excessive vibration, the brackets fail rather than tearing a hole in the HE sidewall. Periodic inspection and a quick repair to the bracket is much more preferable than a ruptured HE. 

That type of bracket weld is no longer used. Instead a circular bracket is used that encircles or wraps around the HE. If anyone needs a part number let me know and I will get it from the boat.