another warm engine

[jim rosenthal]

OK, here goes...one of my engines (port) is running a bit warm at 2400 revs. They are CAT 3116s. Last year I had a temp problem with the starboard one, which turned out to be a sticking thermostat. This is different- when I back off the revs, the temp comes back down. By a bit warm I mean 195 or so; the other one runs at 180. And it didn't use to do this. This is new behavior.
I put a new impeller in that engine this evening and will use the boat tomorrow..we'll see how it acts. My guess is that it will be the same, as the impeller that came out looked fine.
Here's my question- I think the heat exchanger may be scaled up etc. (I don't think there are any impeller chips blocking it up, as it came out intact). Is there a way to flush the heat exchanger in the boat? I am wondering if I could fill it with OsPho or whatever Karl uses, through the winterizing tee, let it sit, and then run it to flush it out. I'm not particularly happy at the idea of taking apart the heat exchanger on this one (last year I did the other just to be safe, and found very little in it, but the process was a pain in the butt). Flushing it through the winterizing tee would be a great deal easier.
(I realize that the seawater intake could be partly blocked and will get a diver to look at it, to cover all bases.)

[Genesis]

Ospho is safe PROVIDED you KNOW there is no Aluminum in the raw water side (better hope not, or you're in for other expensive problems anyway, Ospho or no ospho), and you don't leave it in there for a stupid-long period of time. For pure Ospho 5-10 minutes is plenty to de-scale the H/E.

I know DDs are safe in this regard, but I do NOT know if CATs are. I suspect they are, but I'd check first to be sure, because Ospho will eat aluminum - not that it should ever be used in a raw water system in the first place!

Also, check the showerheads. If you have some gunk in one of them, that will do it. Basically, anything in the raw water path can do this, and particularly anything on the SUCTION Side of the pump needs to be checked - including the hose clamps on the hose from the strainer to the pump inlet (potential airleaks)

[jim rosenthal]

Thanks, Karl. I will check it out with CAT and make sure there is no aluminum in the raw water path. I should also take the zincs out, probably, since the acid might eat them up, a friend suggested. I agree about the obstructions on the seawater intakes- things get sucked up against the strainers etc. However the flow looked good, I think. I replaced the impeller because it needed done and I had one handy.
Interestingly, another post recently mentioned stainless seawater intake screens. I do not use interior strainers- space is at a premium in a 36C engine room. I use large Buck exterior strainers with bronze screens. The holes in the screens are about 3/32". One year I tried SS screens with a tighter mesh, which I got from Groco. They were a disaster. They fouled within a few weeks and I had to change them out. I do not use stainless underwater with the exception of the propeller shafts. Bronze seems better. The bronze screens have not fouled so far. Of course, that may be my problem in the current instance. If acid-treating the HE does not help, I will get a diver to look under the boat and see what's up.

[Genesis]

Yeah, since I AM a diver, my first response to that kind of problem is to toss on a tank and go have a look

[Nonchalant1]

Yeah, since I AM a diver, my first response to that kind of problem is to toss on a tank and go have a look

Karl,

Have you discovered Spare Air? It's a complete scuba tank+reg+2nd stage all in a little bottle affair with a mouthpiece on top, that you clip to your BCD. It's intended to give you 100% redundancy with enough air for a controlled emergency ascent from up to 100 ft. However, at the surface you get 10 or 12 breaths which is just right to "jump in and go see", or take a trip line down to that stuck anchor. You recharge it from your tank.

Doug

PS - Jim, sorry to "mini-hijack" your thread.

[Genesis]

"Spare Air" was designed as an emergency bottle for helicopter pilots, who needed a breath or two to get out of a crashed chopper before they drowned, and where weight and bulk were THE primary items of concern.

It is entirely useless for diving purposes - indeed, it is downright dangerous if you THINK it might save your bacon someday (it won't)

Not to mention expensive.

[Nonchalant1]

OK since I don't take mine to the Carribean for real scuba anymore due to airplane restrictions, but I do use it to get under the boat for a looksee.

Doug

[Genesis]

I had a friend with one who tried to tell me that it was just as good as my second tank in the event of "oh shit!" (I usually dive doubles) In addition, the advertising makes it sound like the cat's azz for recreational diving in exactly the fashion you describe.

So I tried it - I went down to 100', took my reg out, and attempted an ascent on the SA.

Result: "If this had been a real emergency, you would have been dead at 60'."

Needless to say, I gave it back to him!

BTW, this is not to say that you couldn't do a "blow and go" with it from 100'. You could, and you'd get a couple of breaths. However, you'd likely embolize yourself. Contrast this with the fact that you CAN do a CESA from 100' and make it too - the risk is the same, potential embolism or a DCS-II hit that presents exactly like an AGE from arterial bubbling. If I am going to bring redundancy, I want to make a regular, in-control, normal ascent and skip the trip to either the chamber or, if I draw a bad card, the mortuary!

(I agree that it might be ok for a quick look-see, but what if you find that there's something you need to clear or scrape in there? Now what? There's no way you've got enough gas to accomplish that....)

[MikeP]

Have the same situation that occurred this weekend...Brigadoon (53MY, 8V71TIs) runs at around 170 degrees all day at 1500 RPM. When I throttled up to full power for a "clean-out run", the temps came up on the port engine fairly quickly to the 195 range. Dropped RPM back to 1700 and the temp dropped with it. The Starboard engine temp increased as well at full throttle but never got above 180. T-stats are 160's.

Guess I'll be cleaning the intercooler this week sometime using the method Gen described. The boat does not have the gear cooler on the suction side so that shouldn't be a contributing factor. Water pumps are fine with new impellors and re-surfaced cover plates. When I pulled the original (to me) impellors, they looked to be in good condition with no missing vanes so I don't think there is any junk obstructing the tubes although I don't know what had been done on the boat previously. However, the Eng rebuilds (previous owner) were done with tons of silicone sealer which always makes me nervous considering that most people use too much and it just squeezes out and goes who know where. So I guess I'll pull the RW pipes to the cooler and take a look as well.

Any other thoughts are welcome...

[newinlet]

Maybe this will help,

Last week I made a post Re. my 671Ns running warm at higher RPM.

Given the fact I knew the exchangers were clean, the raw water impellers were new, strainers clean,exhaust risers clear and both engines running same temp (checked with I/R Therm.) 2000 RPM & up 195 @ thermostat housing both engines.. Gear coolers not a factor.
This is what I did, A) Drain coolant (lower hose @ oil cooler)
B) Add prestone 10 Min. Rad. flush 2 cans Per. engine mixed with water.
C) Let eng run 20 Min. @ various RPM
D) Drain flush water mix
E) Fill with water & flush again
F) Drain engine
G) Add 2 gallons Global final charge coolant /antifreeze- (contains protection against cavitation & erosion) Add four gallons of distilled water. add water pump lubricant -(Prestone)
H) Clean overflow bottles & top off
I )Sunday, Four hour trip to Boston Water temp 68-72F, RPM @ 2250 Temp Approx` 180 and below, both engines Poblem solved

In the process of tyring to figure this problem out I noticed there was some sediment at the bottom of my over flow bottles, So I thought a flush would not hurt.

Hope this helps, Good luck