3116 & 3126

magster65

New Member
Dec 25, 2007
883
Saanichton BC Canada
Boat Info
2002 model 3788
Engines
Twin Cummins 6BTA's
Could someone please share the basics of these engines... they're both mechanical injector engines? Is one better than the other or just newer model of the same thing? What about the QSM... it's electronic... is it a far superior powerplant or is the 'old school' preferable? Is the electronic engine better at putting around all day opposed to the mechanical.... are they the same and that's not a good idea with this type of diesel? Does Sea Ray put the same transmissions behind all of these?
I've been looking at bigger boats and need some insight on the power...
 
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John, Iam the least qualified person to respond but i can tell you my 3126(420hp) are great. The fuel economy is fantastic. I quit telling people if they asked because they would not believe me. My boat cruise (for me) is about 20mph, around 2000rpm at 20-21gph.
These are approximate numbers as i have only really checked it close once(trip to Bahamas). There are some great owners with these engines that will help you here.
If you are really intrested PM FWEBSTER. Good luck with your search. JC
 
If you do a search on these engines, there's a lot of good info on here. I have the same power plant as JC, only had them for a year but they seem to be great engines.
 
John,

We love our 3116's they require minimal maintenance and are a work horse. We cruise at 2,300 RPM, 26 MPH, and our average fuel consumption is 21 to 22 gallon per hour.

Bill
 
As others said, there's tons of info about these engines. Try searching CSR.

In short, great engines and they're installed on many different models, which means different gear ratio transmissions are used. As far as I recall, both are mechanically controlled engines and have different HP ratings (3116 upto 350HP and 3126 upto 420HP).

We have lots of members with these engines, so you should get much more details if you have specific questions.
 
I can't wait to see what performance I get with the 350HP 3126's. If it's anything close to what is described above I would be thrilled!
 
I burn about 23gph with mine at 21knts. My boat is a lot heavier. You should get better results.
 
The 3116 and the 3126 are the same basic engine except for displacement and fuel pump and injectors.

Neither are electronic, but they are as clean burning as electronic engines and are some of the most fuel efficient diesels available.

The 3116/3126 and the QSM are not comparable and are made by different companies, but the QSM-11 is electronic.
 
I see guys burning 21 gph, and hearing dom's 410da's cruise at 23kts. Last year I ran my boat from ny to florida and back. I have the 375hp 3126s. Ran her at 2250 to 2300 rpm, which is approx 21knts. She averaged 27-28 gals per hour. Both sides burned the same amount of fuel. She did not burn any oil on the trip. WOT is just under 2800rpm. She just turned 1000 hours. I will try to tweak the props before season begins, but is there something else I need to look at? Any other adjustments? Could i have an issue?
 
Remember that there are several factors (tide, wind condition of hull etc) that influence speed, WOT and fuel economy.
If during your trip anyone of a number of these factors is against you then numbers will be affected.
Frank W is your best source to discuss these issues.
 
That's fabulous fuel economy for boats that big. I have some friends with a 330 Carver with 7.4 gas and it cruises at about 18 mph @ 30+ gph. Another pal has a 38 Uniflite with 440 Chryslers... same thing pretty well.
Maintenance wise I'm looking forward to learning something new.
So the boats I'm looking at are the 40 DB and the bigger DA models... most of... or maybe all of have the 3116 and 3126. I spend my summers putting around at displacement speeds. Does this carbon these engines up or does a little 'throttle up' once in a while keep everything ok?
My 'old school' buddies tell me that they need to run at a high % of rated output to live a long happy life. Is this true or no?
 
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In 2009 I spent 6 weeks of the summer travelling down the French Canal system from the English Channel to the Mediterranean, about 1,200 miles. Believe me, the speed was NEVER above 6 knots for the entire trip (usually 4.5 - 5 knots), and when we finally got to an area that permitted opening tbe throttles, a slight puff of black smoke and no problem at all.

So I guess my experience says that puttering along does not show any ill effects at all.

I have since done another 65 hours this past summer, running 105 miles out to the islands of the Baleriacs and back twice, and usually at 2,100 rpm, everything seems fine.

Graham
 
Diesel engines need to be run at rpm's where they are working. If you idle extensively, then expect to see some oil dripping from the intakes and crankcase vent, depending upon your crankcase breather set up. As long as the turbo is spooled, the engine is working, I've got 3116's and a long no wake area and crowded waterway with lots of traffic to transit to get to the Gulf. I run at 1200-1600 rpm....10-15 kts.... a lot and I never have had an issue because of low speeds.
 
Diesel engines need to be run at rpm's where they are working. If you idle extensively, then expect to see some oil dripping from the intakes and crankcase vent, depending upon your crankcase breather set up. As long as the turbo is spooled, the engine is working, I've got 3116's and a long no wake area and crowded waterway with lots of traffic to transit to get to the Gulf. I run at 1200-1600 rpm....10-15 kts.... a lot and I never have had an issue because of low speeds.

I have about a mile of 'no wake' zone to navigate then I'm out of the harbor.

It's true then... diesels don't like being underworked. I can live with that. So the turbos start to spool up at 1200-ish rpm and thats about 10 knots? Not that it matters but what is the fuel consumption at that speed? What speed does it take to be on plane in a big DA?
I'm starting to love the thought of diesels... :thumbsup:
 
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I can run at 15kts which is a nice cruise speed in rough seas. maybe my engines are different, but I start to hear my turbos spool up around 1500 or so rpm's. maybe they're turning lower, but that's about where I start to hear them. I don't think I can go back to gas after diesel, the torque and economy and fuel price and range do it for me. I don't look at hours, I can fill my tanks and run a long time. Just makes sense for me.
 
Fuel use falls dramatically as rpms decrease.

My 350/3116's burn 3.6 gph @ 1200 rpm; 5.8 gph @ 1500 rpm..............Mike's 3126's burn 4.0 gph @ 1200; at 1500 rpm he's burning 7.2 gph.

Trawler speeds.......trawler economy.
 

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