Yearly Maintenance Cost of Deisel Engines

C

Coram Deo

New Member
Nov 15, 2006
66
Severn River, MD
Boat Info
310 Sundancer 2000
Engines
350 Magnum MPI's
I fully understand my question may be to broad to answer specifically but I am starting, just starting, to think about a diesel boat. I now have the 350 MAG MPI's and do most of the maintenance myself. I have done light maint. on small diesel engines on water taxi's and sailboats but not enough to be competent on larger engines.

If I could narrow down the engines, I see mostly CAT's in the Sea Ray, 3116 and 3126 so maybe a good idea of maintenance costs for these. Let's use 80-100 hours per year and a boat in the 40-45 foot range run in the Chesapeake bay area. What does someone pay a Cat guy for yearly maint?
 
Coram Deo,
I sold my '02 320 DA with twin 350 MAG Horizon IBs for an '03 420 DA with C series Cummins 8.3 Liter M3 450s in March '06.

The 320DA engine spaces were so cramped I surrendured after a few bloody knees and knuckles and let my dealer do the maintenance. $110 an hour labor, plus parts.

The 420DA engine spaces are cavernous by comparison. This year I did all winterization and annual services on engines, tansmissions, and gen set myself. Oil, oil filters, racor diesel filters, fleetguard 2 micron engine mounted diesel filters, etc. cost me under $200, and I did all the work myself. I can turn a wrench, but am nowhere near as experienced or as talented as a lot of Captains here at CSR. But I did it, I learned a lot, and am a better boat owner for it...now, when something goes amiss (like a gen set impeller, autopilot, or diesel filter) I fix it myself. My dealer, per the Winter '06 price sheet, would have charged about $4500 for what I did myself for under $1K, including shrink wrap. That feels pretty good.

The only thing I paid Cummins to do (after sea trial, survey, and oil analysis) was to come out and swap thermostats in my starboard engine and perform the 12 and 24 month service on my engines. (previous owner not so much into maintenance..fortunately, he traded her in with 75 hours on the meters) This included adjusting the valve lash on my engines, which I was not comfortable doing myself. The Cummins Power Systems tech charges $1.50 a mile and $88 an hour plus parts. So--around $750 for a day on the boat.

Compared to the 320, my maintenance costs are less now, because so many knowledgeable folks on this board have helped me do things myself.

I've probably not answered your question, but the bottom line is this...a 40' plus diesel boat, Cat or Cummins, will be far easier to work on, and so long as you familiarize yourself with your boat's systems and do due diligence prior to purchase, proper routine maintenance post purchase, including your fuel system, those oil burning, "thundering cathedrals of torque" are a real pleasure to own, maintain, and operate.

With my 320, fully loaded with fuel, water, friends, and all their cr#p onboard, Iwould require turning at or over 4,000 RPMs to stay on plane with a lot of headwind and current. With the 420 and diesel power, I have had 14 people on board, full tanks, loads of gear, and it just does not matter. The boat gets on plane and goes with no tabs and no fuss. I engage the engine synchronizer, accelerate to 2100 RPMs (turbos wind up at 1800 RPMs-- a real kick in the seat) and cruise effortlessly and relax at the helm.

Oh yes..fuel. I ran 147 hours this year, and very little in no wake zones. We logged over 3,000 NM, burned 3,020 gallons of diesel for an average consumption of 20.54 GPH. My average cost per gallon was $2.40. Typically, where I get fuel, 93 octane was in the $3.20 range.

All good.

regards
Skip
 
Annual maintenance on a Caterpillar powered boat is really simple and is technically not as challenging as maintaining a gas boat. You will need an oil change in the engines, generator and transmissions, a new set of zincs, new fuel filters, new oil filters and to clean the washable air intake filters. The cost is:

oil filters = $21
primary fuel filters = $22
secondary fuel filters =$32
generator oil filter =$6
generator primary fuel filter = $6
11 zincs (3116) = $30
13.5 gal of oil =$126 (3 5 gal pails)
4 gal ATF = $32
1 K&N filter kit = $10

After you do it the first time, it will take you a day to do your annual maintenance. While diesel repairs usually take a specialist, routine maintnenace isn't brain surgery and is well within the scope of a do-it-yourselfer....in fact, it is quite easy. So, you can add either $0 if you do the work or 8 hours + travel time and mileage at about $100/hour or roughly another $1000 if you hire the annual service done.

Always use Caterpillar brand filters. They are far superior to parts house brands and are nearly always cheaper than Wix, Fram, Hastings, etc.

There are other Cat maintenance costs that will be foreign to a gas boat owner.......at 250 hours, or if you do not have service records to prove the work was done, the valves and injector timing must be reset. This takes about 1 day and requires specialized tools and knowledge, but no parts. At about the 5th year on a diesel boat you will need to remove and have all the heat exchangers and oil coolers acid cleaned and rodded out......takes about 6 hours, and about $150 in parts and antifreeze. Every 300 hours you will need impellers in the sea water pumps and at about 5-6 years and maybe 600 hours you will need to replace the sea water pumps.

The above is from actual experience in owning 3116's for 10 years. Hope it fills in the blanks for you.
 
Any good marine mechanic should be able to do any of the yearly maintenance items you don't want to tackle yourself and their hourly rate is almost always less than Cat's. There are some items as Frank said such as valve adjustments. and in my case a fuel rail adjustment, that require special tools or gauges that the average mechanic doesn't have and then you'll need Cat to do the work. I'm lucky in that I'm close to the factory and there's a good private mechanic that used to work for Cat installing the engines at the factory.

Greg
 
I have a 480 DB here I take care of with 3196 CAT's. His annual service runs about $800(I'm too cheap). We have the understanding that there will be times when Cat has to be involved. I manage that for him at a reduced rate.
 
The only diesels I've ever owned were small ones on sail boats. But it seems to me, based on observing my dock mates, that timely diesel maintenance is more critical than gas.
 
Sailboats have engines? Oh, that's right! :smt043
 
Besides the way I spelled Diesel in the topic, I appreciate all of the information you all are passing to me. There are a number of 41 foot Sea Rays with gas engines in the area and I have been leary of spending the extra money on diesels for the amount of use I end up having.
I know most of the plus's to the diesels including fuel usage, resale etc, have been following the message board for a while, but not sure if I truly need them for the amount of use and the area of use I find myself in.
As I said I am just starting to think about it, so I am wide open to all that you have been saying.
 
Coram Deo said:
Besides the way I spelled Diesel in the topic, I appreciate all of the information you all are passing to me. There are a number of 41 foot Sea Rays with gas engines in the area and I have been leary of spending the extra money on diesels for the amount of use I end up having.
I know most of the plus's to the diesels including fuel usage, resale etc, have been following the message board for a while, but not sure if I truly need them for the amount of use and the area of use I find myself in.
As I said I am just starting to think about it, so I am wide open to all that you have been saying.
Click to expand...

I would say that diesel would make more sense for you. I inferred you are a low hour per year user. With gas and the quality, or lack of gas these days. I'd be more inclined to go diesel. Gas is extremely susceptible to degrading with time. Diesel will be more stable. There for you won't need to burn off the fuel you have in a timely or ad Sta-Bil to it.

Pat
 
Most discussions of gas vs diesel center around cost, use, and the number of hours per year you run. Those arguments are more valid for commercial vessels than they are for pleasure use.

Often over looked is the drastic improvement in the value of your boating investment. Diesel boats are always in demand and always command a premuim. The depreciation curve for diesels is also quite different. In fact, it is so different that you will probably get all of the extra money you pay for diesels back through about year 10 of the boats age.

And I haven't even gotten to how much more enjoyable running a diesel boat is when compared to a big gas boat.
 
Frank- I'm interested in your comment that big diesels are more enjoyable to run than big gas engines... I'm coming off a pair of 8.1 Mercs and switching to a pair of 8.3 QSCs. I have never run a big diesel boat before. How is it more enjoyable? I'm not challenging your statement by the way, I just want to get a sense of what I have to look forward to and how it is different from gassers! Thanks, Tim
 
For me the biggest change was in the boat's responsiveness with no effort at all.

I went from a 390EC with 7.4 Mercs to the 450DA with Cat diesels. The 390 was a great boat, but I always felt at the mercy of the elements in close quarter handling and in most any sea conditions other than flat calm. The Cat diesels move a lot more water at lower rpms so there isn't as much prop slippage and the boat is much more positively controlled at all speeds. At idle with the gas engines, you have to make the boat do what you want, reaction is slow and sometimes you need some throttle to get things to happen as you want them to. With the Cat diesels, you need to know where the boat is pointed 'cause when you put her in gear, she literally squats and goes there right now. The boat's reaction is immediate and I never need the throttle unless I am in really tight situations and have to stop movement, or need to hurry before a cross wind catches me.

At speeds, diesel boats don't tend to slow down as you punch through heavy seas as gas boats do. They have so much torque and hold the water so well, they just keep on trucking.

I also find the sound of a diesel to be entirely different. In terms of measurable db's, there probably isn't a lot of difference in volume, but I think the diesels are almost a restful sound. They make more of a loud rattle where a big diplacement v-8 makes a loud bellow.

Once a diesel is warm and running, they are tremendously reliable and there is something about hearing a pair of them synchronized and up and running that makes you just know you will get back home when you leave. Every gas boat seems to have its little quirks ad is subject to an occasional miss or hiccup and that always makes me nervous. Even though today's electronically controlled gas engines are very reliable, every owner I know in our marina has had some engine component or smartcrap failure that ended a trip or day on the water with a one-engine ride home.

Some of this may be just opinion, and I'll admit, I am a deisel guy....I have a diesel car, truck, tractor and lawnmower and I'd have a diesel weedeater if I could find one. One thing is for sure, your new boat will be a joy to run and use........no matter what I think aqbout engines!
 
Frank- thanks, your poetic description represents exactly what I think/dream about every night! My dad had an '89 39 Diesel Dancer, and that thing would "bite" at low RPMs just like you describe. He could thread a needle with that thing, and with no throttle or thrusters, of couse. Although my elctronically-controlled gas big blocks purred like kittens, I am so psched to get my hands on the controls of the new boat.

P.S., a diesel lawnmower?
 
lawnmower? actually 2 of them....the one I trim with is a zero turn with a Kubota 3 cyl diesel, and the one I cut the rest of the yard with is a 43hp tractor with a 90" finishing mower on it......I cut about 8 acres and I do it quick.
 
I had to laugh at diesel weedeater! But man Frank... that description was great! You should send that in to SeaRay! I've had my first experience with diesel in my truck for a few months now. I never realized just what low torque meant and how great of a thing it is, but with the bad snow and ice we've had it's been great to get up our steep long driveway with ease. I can only imagine the feel in a big boat! Gawd......when's the boat show here!!??
 
Comparing 7.4 gas engines as representative of gas engines to diesels is not a fair comparison. The 8.1s are a huge improvement over 7.4s and even 502s which were not good at all. The 8.1s make a lot sense on Lake Michigan or any of the great lakes. When you factor in the premium paid for diesel fuel over regular gas in our market, the expensive travel costs and labor rates paid to Cat and other diesel companies, the ease of fixing and availability of gas mechainics, diesels cost more to operate. You don't see huge numbers of 40' SRs with diesels relative to gas. There may be more gas than diesel. Factor in the cost of money and it's not at all clear that diesel is the way to go. I'm not familiar with how 8.1s would push a 40 SR. My 32 foot boat weights about the same as the 40 and with big rudders and props it does fine. We frequently run with a 42 foot Formula PC with no problems keeping up. Following seas and low speed handling are very good. We have to make sure the gas docks pump gas when we come in as attendents have been known to try to pump diesel into the tank if we don't stay on top of fueling. As is always the case, where and how you use your boat drives this decision.
 
Guys, lets get back to the topic, the question is not should I go gas or diesel but rather the yearly maintenance cost of diesels. Let's get back to that discussion. :thumbsup:

Wesley
 
First Born said:
Guys, lets get back to the topic, the question is not should I go gas or diesel but rather the yearly maintenance cost of diesels. Let's get back to that discussion.
Click to expand...

Refer back to the cost of diesel, cost of maintenance, cost of the original purchase price, cost of money, etc....it's not at all a clear cut case especially given good high torgue powerful gas engines likes 8.1s. It's been called the gasoline diesel. :wink:
 
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