Engine Hours

[Motoguy2158]

Wondering how many engine hours people have gone on the original engines with proper care and maintenance. Im currently at 1100 and they are smooth and have the same power as day one and don't use oil. Wondering what others are seeing. I have the 6.2's in a 340 dancer.

 

[hottoddie]

I have personally seen big block go 4-5000 hours. Usually one top end reconditioning along the line.

 

[PlayDate]

Most comparisons put a 1,000 marine hours at 100,000 land miles. But it really depends on how the boat is being used. If 80% of the time it is below 10 knots....they can go forever as long as they are maintained.

 

[Pirate Lady]

Most comparisons put a 1,000 marine hours at 100,000 land miles. But it really depends on how the boat is being used. If 80% of the time it is below 10 knots....they can go forever as long as they are maintained.

My ‘91 7.4 has 600 hours after 30 years. Previous owner took it out once a week to go a short distance, a mile or 2, to swim or fish.
And since i got it in 2020 its never gone over 3400. This engine will easily go 2000 and probably outlive me. Most of the time it runs around 1400 rpm. I should just get a trawler.

 

[Stray Current]

I’m just about to roll 1k (989) and I thought my 6.2 was getting tired. Repitched the props a touch less aggressive and it seems to have woken back up. I think it’s a combination of the boat being heavier than I used to run it and higher intake air temperature down here vs up north. Probably lose a little timing due to that.

 

[mrsrobinson]

If 80% of the time it is below 10 knots....they can go forever as long as they are maintained.

I am not challenging/debating you when I say/ask this: I thought I heard low RPM, martini hull speed cruises were not so good for boat engines? I know when we visit DC we learn that's what most of the DC boaters do though.

 

[Stray Current]

I am not challenging/debating you when I say/ask this: I thought I heard low RPM, martini hull speed cruises were not so good for boat engines? I know when we visit DC we learn that's what most of the DC boaters do though.

definitely not ideal for a diesel, you can wet stack it if you never get the EGTs up. I see it pretty often with generators that run unloaded exercise only. That first run with the load bank to burn it off results in floating carbon embers and lots of smoke as they burn off.

gas engines are better suited to consistently low load operation but it’s still not great for them. Need to get up and run to keep those chambers clean

 

[Motoguy2158]

I’m just about to roll 1k (989) and I thought my 6.2 was getting tired. Repitched the props a touch less aggressive and it seems to have woken back up. I think it’s a combination of the boat being heavier than I used to run it and higher intake air temperature down here vs up north. Probably lose a little timing due to that.

My boat and 6.2's were different engines when i switched to 4 blades

 

[Stray Current]

My boat and 6.2's were different engines when i switched to 4 blades

I tweaked my 3 blades since I damaged them anyway hitting something and they had to go in to the prop shop. I’ll be dropping my 4 blades off to get tuned and I’m hoping for the same outcome

 

[bobeast]

Mine are just under 500 hours. and run like new. I'm usually running cocktail speed but do occasionally blow them out to burn off any buildup.

 

[Shenanigans77]

1,008 hrs on my 6.2’s. They run like tops and use zero oil. I expect them to go to 2,000 hrs at least. Never run it on the stops, its pretty much 3,500-3,600 rpm wherever we are going

 

[mrsrobinson]

So when one sells a high hour cocktails cruise boat should they advertise that, like folks love to do with a car "Oh, those are mostly highway miles" and say "Oh, those are low rpm cocktail cruise hours"

This was meant to be funny. I guess my point is it's a shame "1000 hours" has to have a negative connotation attached to, like 100,000 miles on a car.

 

[BillK2632]

I generally put 30-50hrs / yr on. My SeaRay 185 had just over 800hrs when I sold it, still ran fine, no repairs other than minor / maintenance items. The Correct Craft in my profile had just shy of 2000hrs on the original engine when we sold it. At about 1200hrs we did have to rework the heads due to a manifold failure - it had the old log style manifolds that started leaking and let water into a couple of cylinders - engine continued to run strong as ever after that. If taken care of, most marine engines, especially the older GM based engines can run a really long time, 2000-3000hrs should not be unattainable. Regarding the Mercruiser built engines and the Gen 5 Volvo Pentas based off the GM 5.3 engines - I've not heard anything particularly bad about them, just have not been out there as long as the 5.7's, 7.4's etc - at least not running in boats.

 

[stg099]

Friend of mine is part of a fractional yacht program. The 380 sundancer he's been on for the past few seasons has 5,600 hours on original internals and runs like a top. New bolt on parts throughout it's time but the 496s still perform flawlessly. The company is religious about maintenance intervals and it seems to be paying off. These are the oldest boats in their fleet and they'll be phased out in the next few seasons, but I was impressed at how well these motors have held up.

 

[Motoguy2158]

So when one sells a high hour cocktails cruise boat should they advertise that, like folks love to do with a car "Oh, those are mostly highway miles" and say "Oh, those are low rpm cocktail cruise hours"

This was meant to be funny. I guess my point is it's a shame "1000 hours" has to have a negative connotation attached to, like 100,000 miles on a car.

I agree 100%. I think the 1000 hour engine scare idea came from years ago when automotive engines were converted to marine without any thought as to life since there were no other options. Along comes people like Mercruiser and Crusader who took the GM and Ford blocks and made them into true marine engines. What I hear from Mercruiser Tech support and the mechanics who work on them is todays engines if properly maintained, not run WOT for hours on end and properly winterized and stored should have no problem reaching 2500 to 3000 or more. My purpose for post was to see where people are at, maybe some with bragging rights with mega hours. Thoughts?
No doubt diesels will outlast the gas motors. For many the increased cost upfront and service is a deal breaker.

 

[Skybolt]

I sold my 340 with 1800 hrs on big blocks and the compression was still like new @125-130. New is 135. I am guessing it had another 1800 to go if taken care of correctly.

For what is worth I have 2300 on my diesel(s) and they don't smoke one bit.

 

[northern]

Both 454 have 3,500 hours. Use less than 1/2 QT per 100 hours. Power seems good. We run them at 1400 to1600 but some long periods of 1,900.