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Overheat Badly

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marlinmike

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"I recently purchased a 1997 C

"I recently purchased a 1997 Carver with twin Crusader 350's. I purchased the vessal with the intent of immediately changing out the elbows and gaskets as they were still original equipment - but there was not much rust on the edges of the gaskets. The vessel had spent 10 of it's 11 years in freshwater.
Once my mechanic pulled one of the elbows we noticed the gaskets weren't in too bad of shape and the elbows looked pretty good for 11 years old - but the exhaust tube (at least on the one we pulled to do the pre-inspection on) had blistering on the inside of the tube. This indicated this engine had run hot at one time - but how hot, nobody knows except previous owner/s. The guy i bought it from said he replaced the implellers - maybe that's why.
The oil looks good, the engines run good and don't burn oil. The coolant looks good (but we're having it tested). Anything else you can think of we might take a look at while we're into it? My mechaic said judging from the inside of the exhaust tube the blistering didn't look too bad, which could be an indication the overheating didn't happen too long. He's seen them completely blistered plugged not allowing the engine to run. Any ideas and/or opinions?"
 
"fuel filters .... and the fue

"fuel filters .... and the fuel lines, etc.

What tests are they doing to the coolant? Both alkalinity and freezing/boiling points can be checked easily.

The blister on the exhaust hose indicates it got "hot" but not for too long. From past experience, I can tell you that loss of raw water flow will burn thru the exhaust hose before the overheat warning horn sounds (FWC engines running at 3000 rpm)."
 
"Thanks for the response makom

"Thanks for the response makomark and good idea about the fuel filters and lines - mainly to see if there are any signs of heat deterioration. They were going to test the water for the things you said, plus metal but he said it looked good and clean when he extracted it.
Thanks for your input on the blistering - that's what I was looking for - a second opinion about it. It really wasn't bad - but I didn't know bad from "not so bad". I know the previous owner said he watched the temp gauges religiously and I checked them with a laser - so I know they're pretty darn close. The mechanic is also going to clean up some cracking in the fiberglass on the mufflers (too tight of clamps), seal an exhaust leak on the generator, replace the blowers and foam up the bulkhead to shut up those CO monitors.
Sounds like all is well and we'll be up in the San Juan's before you know it :eek:)
Thanks"
 
"I might have missed it, but d

"I might have missed it, but did you do a compression check? As he said running hot if caught quickly is not necessarily a bad thing. In the late 60's and early 70's it wasn't uncommon when folks purchased a new vehicle to run them extrememly hard (running them hot). It was a pseudo break-in that from my experience either 1) killed the engine or 2)yielded an engine that performed at peak and flawless.

Now however with so many different metals and expansion rates of those metals, I wouldn't advise it on purpose.

I accidentally ran one of my crusaders hot (I don't know who shut that water off while I wasn't looking). I caught it when it started steaming more than normal through the exhaust. I was petrified and rechecked everything on the engine, to include raw water impeller. Everything checked out fine and since that incident the compression between all cylinders evened out and my oil usage dropped."
 
"not bad in terms of engine da

"not bad in terms of engine damage ....

it sure wasn't cheap fixing it that day so we could fish the next...i hate paying retail +.

Good idea on the CR check; probably wouldn't hurt to change the plugs, too, if you do."
 
"Mark is right on with the hos

"Mark is right on with the hose burn through. I had the same thing happen and it burned the muffler as well as the hose. Fixed all the riser/elbow problems and haven't had any problems since. But what you really need to worry about is that CO problem. If you have kids on the boat, the CO can really damage their health. Not to good for us older folks either. Been in the fire service over 25 years and seen some bad health problems from too much CO. If those monitors have been going off a lot you might want to replace them also. The sensors inside can become saturated and not alarm till the CO level is really high. You should replace them before spending too much time or sleeping down below. BOAT SAFE!!!!"
 
"Thanks guys for all your advi

"Thanks guys for all your advice. I've not done a compression check but don't think it to be a problem. Previous owner says it doesn't burn oil, I can vouch for that and there is no excessive oil exhaust cold, deaccelerating, etc. At 380 hours now (pretty good for a 1997) I don't think compression was affected - especially after hearing of these hose burn throughs. One thing I am going to do though is get those sea strainers the previous owner bought installed. And (some good advice Big Al) change out those CO detectors."
 
"Big Al,

Do FUME detectors

"Big Al,

Do FUME detectors ever detect false alarms? I have one in the bilge...just wondering"
 
"AL: Almost any type of detect

"AL: Almost any type of detector is subject to a false alarm. Good thing or I might be out of a job. A fume detector is usually a sensor down below, or anywhere fumes can accumulate, and a warning device at the helm. Some are the point of contact type but a buzzer down below might be hard to hear. Gas fumes usually seek low areas so in the cabin would not be a good location. I don't believe that the sensors will saturate like a CO detector. If you can find where the sensor is in the engine compartment, make sure that it isn't near a forced air source, ie fan motor, breather intake, and is clean. Of course one of the best fume detectors is the old beak. Probably not the most healthly thing to use but just a small amount of gas fumes can be smelled easily. If you get an alarm, don't turn anything on, except the blower, and give it the ole' sniff test. And like I tell most folks, if the system is over a few years old and you think there is a problem, replace it. Problems at the dock always seem minor compared to the same problem 20 miles out!"
 
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