How many hours is a lot?

[sbbamafan]

Re: How many hours is a lot?

I have over 1100 and it runs like new. Furthermore, it has needed very little maintenance over the years.

 

[Gosub]

Re: How many hours is a lot?

My 5.7 Merc is in a thousand pieces on a bench right now waiting for a new crankshaft. Inspecting the rest of the engine is like looking at a freshly run in, new motor.

The crankshaft and 3 of the conrods are junk.... thanks to a failed oil pump!

The moral of the story for me is that you can be like a mother to your engine and it can still die of heart failure.

 

[Mason78]

Re: How many hours is a lot?

I have been told that boat engines work much harder than car/truck engines, but I am no expert.

My boat has over 400 hours on the 5.0 Mercruiser and runs great.

 

[Mason78]

Re: How many hours is a lot?

I have been told that boat engines work much harder than car/truck engines, but I am no expert.

My boat has over 400 hours on the 5.0 Mercruiser and runs great.

 

[dingbat]

Re: How many hours is a lot?

The root cause of 98% of all recreational marine engine failures is poor fuel system maintenance and water ingestion. Anyone who has spent a lot of time around marine engines knows that age and hours means little. It’s all about maintenance and condition

Comparing fuel usage and RPM is a completely useless measure because it does not take into account the root cause of death in 98% of the failures. Kind of like comparing the life expectancy of an office worker to a tight rope walker by comparing the number of steps each walks in a day.

Hours are irreverent. I could care less about the hour gauge. I want to know the condition of the motor. How long has the owner neglected the maintenance on the boat?

I can learn more about a motor by just lifting the engine cover and looking around. The way someone keeps their boat tells me more about it's condition than an hour meter could ever tell me. Dirty, oily engine forget it. Fresh oil changes, mid-season, set off the alarm bells as well. If I get past the visual inspection and fluid check its time for the compression gauge. Only then will you know the true life expectancy of that motor.

 

[Fireman431]

Re: How many hours is a lot?

Not arguing your points whatsoever and appreciate your input but out of curiosity where are your numbers derived from?

My own personal experiences, three different sources that are marine certified mechanics and run their own businesses, and the MMI technical online manual. All answeres given here were median numbers derived from these sources.

 

[rallyart]

Re: How many hours is a lot?

The hour meter on my old Grew with a 470 in it died twice. There did not seem much purpose in continue to replace it.
The engine however has over 3000 hours and was run very hard and over revved commonly when it was young. Probably has 3500 hours but that really doesn't matter. It now has some smoke but does not yet 'need' a rebuild, although that would be a 'nice to have'.
We did regularly change the oil and it has only spent one night completely underwater.
I'm not a fan of 'hours' as a measure of the engine. A leakdown test or even a compression test is more useful. A good maintenance record is the best bet.

 

[laserbrn]

Re: How many hours is a lot?

I agree that hours on the engine aren't really a measure of anything. It's not so much like a car where you can average things out and get a good idea on the condition of the engine by the mileage that's on it.

I have a 30 year old 454 in my boat right now with about 1000 hours on it. It's in worse shape then a 10 year old engine with 2000 hours on it. A lot of the damage comes from non-use as much as use. I agree that the real test of an engine's condition is a compression/leak down test. If it all checks out there it's good to go.

 

[ssobol]

Re: How many hours is a lot?

Boat engines (and airplane engines) spend a majority of their lives running in the top end of the power curve (at or near design power). This puts a lot more strain on the engine than what you would find in a car or truck.

Your average passenger car engine rarely gets above half power and almost never above 3/4 power even when driven aggressively (face it there are no places where you can really exercise your car even if you wanted to unless you have access to a race track).

Your best bet is to run the engine at a constant speed after it is completely warmed up to normal operating temperature. Changes to the power setting should be done as gently as possible (no more hole shots).

If you treat it properly the engine should out last the rest of the boat, but it'll take a lot of the fun out of boating.

 

[MH Hawker]

Re: How many hours is a lot?

I have a real simple answer to this, run them till the puke and die and get a new one.

 

[hostage]

Re: How many hours is a lot?

I don't think hour meters matter much. You can always disconnect them. I don't even have one (19ft Cuddy).

The most common advise in regards to powerplants and used boats is avoid the old ones you can't get parts for. When it comes for boats in general, having good stringers, a deck, and a transom are one of the most common suggestions. A test drive is a good way to see if the engine is preforming or even turning over. Other than that checking the Oil for water and you can always do a compression test on the spark plugs.

Your question is interesting, though there is no answer and it is all up to interpitation and opinion.

 

[sasada]

Re: How many hours is a lot?

The root cause of 98% of all recreational marine engine failures is poor fuel system maintenance and water ingestion. Anyone who has spent a lot of time around marine engines knows that age and hours means little. It?s all about maintenance and condition

Comparing fuel usage and RPM is a completely useless measure because it does not take into account the root cause of death in 98% of the failures. Kind of like comparing the life expectancy of an office worker to a tight rope walker by comparing the number of steps each walks in a day.

Hours are irreverent. I could care less about the hour gauge. I want to know the condition of the motor. How long has the owner neglected the maintenance on the boat?

I can learn more about a motor by just lifting the engine cover and looking around. The way someone keeps their boat tells me more about it's condition than an hour meter could ever tell me. Dirty, oily engine forget it. Fresh oil changes, mid-season, set off the alarm bells as well. If I get past the visual inspection and fluid check its time for the compression gauge. Only then will you know the true life expectancy of that motor.

Poor fuel system maintenance ruining an engine? When I think of "ruin" I think of needing a major overhaul or new/reman in order to function as intended. What type of fuel system neglect would cause catastrophic failure?

 

[laserbrn]

Re: How many hours is a lot?

Hahaha....I've been living a fuel system neglect nightmare! Boat sat for 1.5 - 2 years. Original owner sold it to a kid at the marina and he specifically told him not to use the tank in the boat because it's a 20 year old steel tank and should be replaced. He told him not to use the gas in it as it's old and bad and would jack everything up. The kid was only interested in flipping the boat for a quick buck and figured he'd just shoot a quick youtube video of it running.

Well, that was the last time it ran. Now that I've bought the boat I'm living the consequences of his mistake, but I did then get the boat for nearly nothing. So....6 broken pushrods in the motor which means six stuck intake valves. Because of the age and condition of the engine I've decided it's time for a full rebuild although likely a valve job would do the trick.

The tank on the other hand has now been leaking the gas he added to it because he figured it would dilute the bad gas and "freshen it up". So I got to deal with a boat with a bilge full of gas and and uknown number of gallons of bad gas. So far I've cleared the bilge once and it filled up again so I'll get the joy of doing it again tomorrow. I've drained 15 gallons of gas out of the boat and I don't know how many more gallons are in there. I can only dispose of 15 gallons of gas at a time and the place is only open on weekends.

You can do a lot of damage and cause a lot of problems with a little fuel system neglect.

 

[dingbat]

Re: How many hours is a lot?

Poor fuel system maintenance ruining an engine? When I think of "ruin" I think of needing a major overhaul or new/reman in order to function as intended. What type of fuel system neglect would cause catastrophic failure?

Do you consider fixing a piston sticking out the side of the block or a melted piston a major overhaul?

Lean out your Johnson tiller, or any motor for that matter with a plugged filter, a vacuum leak in a fuel line, a clogged jet or dump a pint or two of phase separated fuel in your carbs and get back to us with the results.

 

[sasada]

Re: How many hours is a lot?

Do you consider fixing a piston sticking out the side of the block or a melted piston a major overhaul?

Lean out your Johnson tiller, or any motor for that matter with a plugged filter, a vacuum leak in a fuel line, a clogged jet or dump a pint or two of phase separated fuel in your carbs and get back to us with the results.

We are not talking about 2strokes Mr Niceguy! Try taking on your prop with your over-excercised jaw/finger tips and dont get back to us with your results.

I asked an honest question and dont expect a wiseazz answer...

 

[04fxdwgi]

Re: How many hours is a lot?

My 20 year old Mercruiser 7.4L has 1298 hours on it and still purrs like a kitten. Has 40# oil pressure at idle / 4300 rpm / hot / or cold and doesn't use a drop of oil between changes. Good maintenace is king in getting long life out of an engine. Of course, things happen that one can't foresee, but that is with any engine. . Have seen em die with less than 100 hours on them, but have also seen them live in excess of 50 yeras. Friend just bought a '51 mahogany boat with the origional, untouched 4 banger engine and it runs amazing. Heavens knows what the hours are.

 

[oldjeep]

Re: How many hours is a lot?

I've pretty much come to the point I think an hour meter is the most useless thing installed in boats. Honestly, it tells you how many hours the key was on and has little or nothing to do with the engine/drive condition.

To some extent I agree, but it depends on what sort of hour meter you have. The one in my boat has an inductive trigger off a plug wire, so it only counts when the boat is running.