Cat 3126 owners

Sparky

Lieutenant
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Oct 21, 2011
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Location
Portland, ME
Boat Make
42' Glasspec, 450 John Deere
Cat specs special ($$) cat oil for this engine in marine environment. Straight 30 weight. Does anybody know why? And has anybody had problems that were associated with not using it?
 

steveinak

Admiral
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Sep 1, 2011
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Location
Piker Central
Boat Make
31 BHM
Cat specs special ($$) cat oil for this engine in marine environment. Straight 30 weight. Does anybody know why? And has anybody had problems that were associated with not using it?
A good friend of mine has one in his lobsterboat, 7000+hours on it and all he uses is Chevron Delo.
 

lobstercatcher

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Cat specs special ($$) cat oil for this engine in marine environment. Straight 30 weight. Does anybody know why? And has anybody had problems that were associated with not using it?
I never heard anyone say anything good about any cat engine starting with 31xx .
I believe it is the worst motor made in the last 40 years
 

Helen L

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Jan 12, 2012
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I never heard anyone say anything good about any cat engine starting with 31xx .
I believe it is the worst motor made in the last 40 years
I think the problem is they are putting out way too much HP. 420 HP is pretty much maxed out as well. My old man had 3126s w/385 HP each. Cruising was supposed to be at 2200 RPMs, he never ran over 2000, 1800 most of the time. 250 HP would be nicer. Just my thoughts, I'm no expert on them. My 671 has about the same displacement and had 180 HP before the turbo was added for 250 HP.
 

lobstercatcher

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I think the problem is they are putting out way too much HP. 420 HP is pretty much maxed out as well. My old man had 3126s w/385 HP each. Cruising was supposed to be at 2200 RPMs, he never ran over 2000, 1800 most of the time. 250 HP would be nicer. Just my thoughts, I'm no expert on them. My 671 has about the same displacement and had 180 HP before the turbo was added for 250 HP.

I'm not a fan of any cat only beecause of what I observe around the harbor compared to other brands. I really don't know what makes cats tick. Just think there are better choices out there.
 

Sparky

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Oct 21, 2011
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Location
Portland, ME
Boat Make
42' Glasspec, 450 John Deere
I know there were block issues early on that tarnished the reputation of the engine. But I hear cat worked with those people and could tell if yours was good or bad by it's serial number. They're are a bunch of em out there w a lot of hours. Keep it wheeled right and out of the corner, it should last.
 

Pedlyr

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Aug 31, 2011
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Southern RI
20 years ago when CAT was busy they outsourced the casting of some blocks to France. Guess how that turned out.

The 3126B is a HEUI. Just like a International 7.3. That means it uses some lube oil and pumps it into the injectors for use as a hydraulic mover of each injector plunger. AKA as a Hydraulic Electronic Unit Injector. The computer uses solenoids to regulate what fuel gets used at each injector.

As you can imagine, oil viscosity is an important part of this as is clean oil.
 

Reelman955

Lieutenant Commander
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Dec 15, 2011
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Location
South Shore Long Island
Boat Make
2007 Seaworthy/BHM 315 Yanmar
I believe that the 3106/3126 had gotten some negative reviews when they were an option in sea rays. I think there was issues with the setups. not the right props putting to much strain on motors that were being run at too high of a rmp for the get up on plane and go sea ray owners. that said, I have a good buddy with almost 6000 hours on a 3106.
 

tunafishhkg

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Oct 13, 2011
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Cape Cod MA/Hong Kong SAR
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35 Duffy
Got to keep an eye on the aftercoolers on the 3126 especially early models at 450HP other than that, prop 50-100 over rated at full battle loaded weight, Run no more than 2400, you should see good service. Soft block was on the 3116 and any good 30Wt oil like shell rotella or ursa is good. Tag on oil container will say approved for cat and all engines it is approved for. 15-40wt was the norm on the early 31 series engines till the HEUI syst, then cat spec all 31 series to 30wt. Pedlyr reasons make sense.
 
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