Official Caterpillar3116/3126 Thread

ttmott said:
To add what @dtfeld was saying - Cat ELC if not changed per guidelines will form a "slime" on the internal surfaces of the engine and inhibit heat transfer. Not saying this is the issue but one of the reasons to keep to the maintenance regiment.
The first thing I'd check is the gear cooler and see if grass or other debris is starting to restrict flow. The gear cooler is the choke point in the raw water loop. And the engine coolant pump belt. Quite possibly the idler pulley has loosened up and that belt is slipping.
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I think Tom may be on to something here.

Edit: You can open the raw water side of the HEX to look, without dumping the coolant as well.
 
ttmott said:
No coolant on the gear cooler; just raw water. Just pull the hose off of it and look in there.
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Post interupted by coffee drinking...gear cooler as Tom mentioned (I'd look there first) but the main HEX can be inspected pretty easily as well.
 
What a D.A. The circulating belt was a little loose. I thought I checked it. (Too much on my mind). Anyway, we will see on the ride hope. Thanks guys in advance
 
Progress. Port engine placed in engine bay.
Have a question about torque for flange bolts. ZF85IV manual state 74ftlb, is that correct?
Doesn't that vary (reduce) if you use oil on the threads?
What about the propeller shaft end Nylock nut?

IMG_0776 copy.jpeg
I swear that engine and engine bay were spotless just a few days ago.

Was stressing over alignment of the engine to the shaft, especially lateral adjustments. Turned out I had a breaker bar that was the perfect size. Took the time to sand the mount locations, then added light grease coating. Made all the difference.
Used .004 as the tolerance around the flange mating surface.
 
I wouldn’t overthink it. I have never thrown a torque wrench on those. I’ve done 5 and never had a problem. I’m not saying I’m right. Just saying I wouldn’t sweat it
 
Riptide III said:
I wouldn’t overthink it. I have never thrown a torque wrench on those. I’ve done 5 and never had a problem. I’m not saying I’m right. Just saying I wouldn’t sweat it
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That flange looks a lot like the four on the Chinook main transmission, hence the angst. Not like this boat has to hover with the ramp on a hillside.

Have a good 4th
 
Last question on the shaft and coupler. How much does one tighten the nut on the end of the shaft?
Is it until the cotter pin hole is exposed, or until some of the threads are visible?

IMG_0781 copy.jpeg
 
SCFoster said:
Last question on the shaft and coupler. How much does one tighten the nut on the end of the shaft?
Is it until the cotter pin hole is exposed, or until some of the threads are visible?

View attachment 146920
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I did it until tight, about 2-3 threads showing. You could snug it up after running the boat and the taper full sets, that nut only holds the shaft on in reverse
 
ttmott said:
Mr. Webster (@fwebster ) is not an advocate of prefilling the final filters. But I'll let him address that.
I do but through a Mr Filter funnel on my QSM11's; those filters hold a lot of fuel. I never pre-filled on the 3116 Cats; followed exactly what my mechanic said.
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Where CAT says don't prefill final filters I'm guessing that to avoid unfiltered fuel getting into the motors , it was simpler to advise just don't do it , as opposed to explaining that the outside of the filter must be filled only. Plus to a novice or a distracted person, that centre section looks like it's just asking for fuel to be poured in. But with a Mr Funnel AND only using the outside of the filter, I reckon it's fine on a 3116 also, that's what I did last time. Also when I've used the priming pump I never undo the nut to let air out , it shoves the fuel thru the system with probably a smattering of air but startup is always a doddle.
 
Pgeee said:
Where CAT says don't prefill final filters I'm guessing that to avoid unfiltered fuel getting into the motors , it was simpler to advise just don't do it , as opposed to explaining that the outside of the filter must be filled only. Plus to a novice or a distracted person, that centre section looks like it's just asking for fuel to be poured in. But with a Mr Funnel AND only using the outside of the filter, I reckon it's fine on a 3116 also, that's what I did last time. Also when I've used the priming pump I never undo the nut to let air out , it shoves the fuel thru the system with probably a smattering of air but startup is always a doddle.
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People over think this. Keep in mind there are screens on the individual injectors also. The caution is really around construction equipment and the three inches of dirt and grease all around the filters.
 
ttmott said:
People over think this. Keep in mind there are screens on the individual injectors also. The caution is really around construction equipment and the three inches of dirt and grease all around the filters.
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our old gas engines barely had an air filter! Marine environment (should) be pretty clean compared to the rest of the use-cases, I’d think.
 
all true, however, I'd bet the orifice in a diesel fuel injector is way smaller than the jet in a carburetor.......

BEST !

RWS
 
Pushed the throttles all the way forward for the first time yesterday since bottom painting and changing the racors. She quickly jumped up to 2800 at 30mph. Felt good, but I feel like she was a little better 12 months ago, anecdotally.

Are these numbers where she should be? If yes I will stop checking.

Also is there any advantage to pushing them to WOT occasionally for short periods?
 
I believe you run full throttle for something like 5 minutes per hour. It’s good to blow out carbon and stuff from the turbo etc.

2,800 is what you want to hit at full throttle underway. At the dock, in neutral you should see 3,100.
 
mrsrobinson said:
Pushed the throttles all the way forward for the first time yesterday since bottom painting and changing the racors. She quickly jumped up to 2800 at 30mph. Felt good, but I feel like she was a little better 12 months ago, anecdotally.

Are these numbers where she should be? If yes I will stop checking.

Also is there any advantage to pushing them to WOT occasionally for short periods?
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This looks pretty good and right at what I get. As long as the RPMs are 2800 or a little more all is well. Nothing wrong with a little a WOT as necessary. I do it occasionally, and I keep track of RPM, speed, boost and EGT.

Speed of the boat can and will change with the load and bottom condition.
 
With my prior gas engines I was coached to open them up occasionally to blow out the carbon build up and such, was curious of diesels needs the same.
 
mrsrobinson said:
With my prior gas engines I was coached to open them up occasionally to blow out the carbon build up and such, was curious of diesels needs the same.
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I’ve never seen an official requirement from CAT about running the engine at WOT other than its expected a certain amount of the time.

I think idling around for extended periods without getting into the power band with the turbo producing boost is just as bad. I don’t think you need to go to WOT to achieve this, just a good run inthe usual cruising RPM range 2000-2400.
 
Caterpillar marine engines application and installation guide says

Prolonged low load operation should be followed by periodic operation at higher load to consume exhaust deposits. Low load operation is defined as below approximately 20% load. The engine should be operated above 40% load periodically to consume the exhaust deposits. Caterpillar engines can be run well over 24 hours before exhaust slobber becomes significant. The amount of additional time depends upon the engine configuration, water temperature to the aftercooler, inlet air temperature to the engine and type of fuel.

Quite a lot of interesting information in this guide
http://www.propellerpages.com/downl...ngines_Application_and_Installation_Guide.pdf
 
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