Looking at 2003.5 DA 340: Engine Hours Guidance

[Michaelkm8]

Hi All,
I've been looking for about 2 years now and appreciate all the help and feedback I've gotten on this forum. I think the time is near for me to pull the trigger and am looking for some last tidbits of knowledge.

I was originally looking at the 2004-2008 DA 320's with around 500 hours on the Mercruiser 6.2 Horizon V- Drive's.

However, some suggested that the DA 340 with the 8.1's are a really good step up and to look back a few years to get it in my price range.

There are only a few 2003.5/2004 340 DA's (I like the layout better than earlier years) in my area, but they all have around 1000 hours on the engines. I'm not looking for absolutes, but am curious what the average for these engines are?

If I'm looking to put 50-100 hours a year on these guys is it reasonable to expect 5 seasons before major repairs or engine replacement?

Again, just looking for some input, not an absolute number here.

Thanks in advance.

 

[Strecker25]

1000 hours certainly isn’t any sort of death sentence you’ll see a lot of people mention, nor is 150 hours an indication an engine is like new. On a 2004, that’s only 50 or so hours of runtime a year.

Get a compression test done, ask for oil samples, and run the boat at WOT during the survey to ensure it makes proper revs. If all that checks out, good to go.

The 8.1’s in some years did have stainless steel exhaust risers which caused some corrosion issues, so that may be worth researching a bit. They may have been changed by now, though.

I’ve been on that exact boat and power package and it flies

 

[northern]

We have 1989 twin 454 with 3600 hours. No oil consumption. Maintenance is key to good engine life.

 

[Michaelkm8]

1000 hours certainly isn’t any sort of death sentence you’ll see a lot of people mention, nor is 150 hours an indication an engine is like new. On a 2004, that’s only 50 or so hours of runtime a year.

Get a compression test done, ask for oil samples, and run the boat at WOT during the survey to ensure it makes proper revs. If all that checks out, good to go.

The 8.1’s in some years did have stainless steel exhaust risers which caused some corrosion issues, so that may be worth researching a bit. They may have been changed by now, though.

I’ve been on that exact boat and power package and it flies

Thanks for the advice!

 

[Michaelkm8]

We have 1989 twin 454 with 3600 hours. No oil consumption. Maintenance is key to good engine life.

For sure. I'm handy around cars, so boats shouldn't be a huge leap. Do you do any maintenance yourself? I find that after a few runs it's easier and faster that way then to constantly bring it to the shop.

 

[BillK2632]

Like already mentioned, 1000hrs seems to be (and wrongly so) an indication the engines are at the end of their life. Truth is far from that -- assuming they have been maintained. Nothern's 3600hrs is a unicorn, but shows these motors can last with proper care. I personally put 2000hrs on our old Correct Craft (Commander 302), I maintained it and it was running perfectly. Also my old SeaRay 4.3 had over 800hrs, again maintained and running just fine. My Cobalt has just under 300hrs and still smells new.
So, my thought is, on an older boat higher hours has to be expected if the boat was used at all -- a thorough engine inspection is a must. Salt, corrosion, low use is what usually kills a marine engine.
Another way to look at it, realizing a boat engine runs at different loads that a car, but a car engine that say averages 45mph, 1000hrs = 45,000mi. With that thinking, my Lexus with 153k has been run @3400hrs! It also has had no repairs other than maintenance. Granted not quite the same, but we put 1000's of hours on our car engines, but really only pay attention to miles.

 

[Strecker25]

Like already mentioned, 1000hrs seems to be (and wrongly so) an indication the engines are at the end of their life. Truth is far from that -- assuming they have been maintained. Nothern's 3600hrs is a unicorn, but shows these motors can last with proper care. I personally put 2000hrs on our old Correct Craft (Commander 302), I maintained it and it was running perfectly. Also my old SeaRay 4.3 had over 800hrs, again maintained and running just fine. My Cobalt has just under 300hrs and still smells new.
So, my thought is, on an older boat higher hours has to be expected if the boat was used at all -- a thorough engine inspection is a must. Salt, corrosion, low use is what usually kills a marine engine.
Another way to look at it, realizing a boat engine runs at different loads that a car, but a car engine that say averages 45mph, 1000hrs = 45,000mi. With that thinking, my Lexus with 153k has been run @3400hrs! It also has had no repairs other than maintenance. Granted not quite the same, but we put 1000's of hours on our car engines, but really only pay attention to miles.

that's pretty spot on - my 1/2 ton silverado has an hour meter and at 37k miles has about 1,010 hours on the engine.

 

[Stee6043]

that's pretty spot on - my 1/2 ton silverado has an hour meter and at 37k miles has about 1,010 hours on the engine.

Same. My Sierra just ticked past 1,600 hours at 52k miles. Prolly should think about scrapping it soon

 

[Strecker25]

Same. My Sierra just ticked past 1,600 hours at 52k miles. Prolly should think about scrapping it soon

yep! much like marine engines, our cars and trucks typically die from salt and rust

 

[Espos4]

Hours may not be the best correlation between marine and auto engines.

Gallons of fuel used may give a better perspective because marine engines operate at much higher loads than auto engines.

I average 6.5 gallons per hour throughout the season in a 24’ boat. That’s 12-15 gph cruising down to 1 gph idling.

Extrapolate that out with say an 18 mpg pickup,
6,500 gallons (over 1,000 hours) X 18 mpg = 117,000 miles.

8.1’s in a bigger boat may average 8-9 gallons per hour?

That’s closer to 162,000 miles.

 

[TTG]

I’ve never understood this parallel concept with boat motor hours and your vehicle hours/miles. When was the last time you took your vehicle on 3hr road trip at RPM’s higher than 3k non stop? Not to mention the weight difference. Your vehicle doesn’t weigh over 10k lbs. Yikes.

Above are some great example to check for engine condition. My 8.1’s have close to 900hours and run strong. Maintenance is key. My previous boat with 8.1’s (3470…I know not a Searay) had about 1200hrs. Person I sold it to a few years back still has it….keeps on rolling.

 

[boatrboy]

8.1’s in a bigger boat may average 8-9 gallons per hour?

You may be off a little . At cruise (~27 mph) my 340 burns about 32 gallons per hour.

 

[Stee6043]

I’ve never understood this parallel concept with boat motor hours and your vehicle hours/miles. When was the last time you took your vehicle on 3hr road trip at RPM’s higher than 3k non stop? Not to mention the weight difference. Your vehicle doesn’t weigh over 10k lbs. Yikes.

Above are some great example to check for engine condition. My 8.1’s have close to 900hours and run strong. Maintenance is key. My previous boat with 8.1’s (3470…I know not a Searay) had about 1200hrs. Person I sold it to a few years back still has it….keeps on rolling.

Trying to correlate boat motor hours to vehicle motor hours is no less arbitrary than suggesting gas boat motors are generally going to be garbage at 1,000 hours (which is common internet knowledge ).

Size/weight probably isn't the best argument. My truck weights 5500 lbs +/-? And she's only got a single 6.2L engine. My 340 weighed 11,200lbs dry and had the luxury of two 7.4L motors to push her around. Of course my 400 is more than double that with the same engines so...well...it was worth a shot.

 

[Espos4]

You may be off a little . At cruise (~27 mph) my 340 burns about 32 gallons per hour.

32 gallons across 2 motors.

So 16 gallons per hour each cruising.
1-2 gallons per hour idling.

The 8-9 gallons per hour was a guesstimate across all hours of usage.

How many total gallons did you use last year?

 

[boatrboy]

32 gallons across 2 motors.

So 16 gallons per hour each cruising.
1-2 gallons per hour idling.

The 8-9 gallons per hour was a guesstimate across all hours of usage.

How many total gallons did you use last year?

Ah - re-read your post again and I see you are talking about averaging over "usage"... Got it

 

[BillK2632]

This is all good stuff - comparing it to miles in a car or gallons used (I know a lot of diesel engines do this) are all good comparisons. What I think the message to the OP (or anyone looking at an older boat) is that contrary to some popular opinion, 1000hrs on a well maintained engine is not EOL at all, it's really more middle age. A properly maintained 1000hr engine has a lot of life left.

 

[Michaelkm8]

Really appreciate everyone's input here. Seems like 1k hours isn't something to be concerned about.

 

[unsalted]

Start with the same concern for the 1000 hr engine as you do with the 100 hr engine. They are all suspect until you get the results of compression tests and make sure that at WOT they meet rpm expectations. I don’t know much about oil sampling but it seems a single sample is hard to use in understanding condition. It would be better if the seller has maintenance records and a history of samples.