What is Considered High Hours on an Engine?
 

My 2011 300 XS's currently have 350 hours on the clock. Well maintained every season, never had any issue with them.

Time to replace the boat, I assume that prospective buyers would prefer lower hours on the engines.

I am curious to hear your thoughts on what you consider to be high hours if you are considering buying a used boat?

Doesn't sound like a ton of hours. The question is what the RPM breakdown looks like.

I had the same approach when discussing it with a potential buyer stating that 97 % of the hours were done at low rpm (800-2000).

The reply was, if you are selling a Ferrari with 30,000 miles, no one will care about the rpm data, it's too high mileage.

I would say it depends on which motors. I don't know anything about outboards but 300hrs on blue motors would be high hours but 300 on black motors would be no big deal.

Break it down to years. You have 60-70 hours per year roughly. That sounds like a lot of boating per year. If it was 350 hours on a 2000 then it sounds minimal. It's all relative. When I should my 83 century it had about 350 hours on the 440 in it. Ran strong and was considered very low hours. The buyer sounds very fussy or a tire kicker. I wouldnt worry about it, someone will buy it with those hours.

Depends how well its all been maintained from day one. Customers boats that I have maintained with 1200 hours in better condition and running conditions than new customers boats with 50 hours on it.

97 % of hours at 800 to 2000 rpms is not were an engine should spend its time to help with motor longevity. Actually that is like lugging and trolling the engine all the time.. Kind of like sitting idling your car 97 % time. Not going to last. Most marine engine run rich at very low rpm's and 2000 rpms is lugging a marine engine. That's like running your car up a steep hill all day in 5 the gear lugging the hell out of it.

You want marine engine that has ran most of its time at 70 to 75 % of its duty cycle.

Just an Example MAX - WOT 6000 RPM's - a good place to see rpms at would be 4000 to 4500 most of its run times.

I'm curious about this. Blue motors are built with better parts, shouldn't they last longer? Or is this because black motors don't make enough power to hurt themselves?

A better measure would be pounds of fuel used over the life of the engine.

Blue motors need the top end gone thru every 300-350 hours. Black motors are basically production truck engines and meant to run forever.

Depending on the builder, some 1 hour is high... :rolleyes:

Some of the U.S. Coast Guard boats down here in Baltimore have 300's on them with over 3,000 hours. Other than normal maintenance nothing has been done to them.

What was that old saying? If it's not running its rusting...or similar. I would prefer the set with 350 hours over five (recent) years time instead of low hour motors like 350 hours over fifteen years.

Don't those 300's run 1,000 hours if well maintained? If so the 350 hours on yours is sounding like a positive.

We've got a '09 250 Pro XS with a shade over 800 hours. Runs like a champ and clean as a whistle. I'd say you're good.

This is how I think. My boat only breaks when it gets mad for not having fun.

Thank you for the feedback so far.

Was told that the hours on the engines would reduce the sale price of the boat by at least 10 K on a 100K purchase

I say bs on the 10k. Sold my 496 fountain 2 years ago for 35k. 800 hours. Clean one owner, but still 800.

I think if you look hard. Mercury probably did endurance life test on that motor.

I know a Tow Boat US boat that has 7000 hrs on the 496 with nothing other than routine maint. I just clocked 400 on my 496 and she is still purring.

No way. That is not a lot of hours. You'll also be amazed at how much the idling time adds up. When I scanned my 525 I had 386 hours, 161 of them below 749 rpm (idle) and only 14 hours above 4,000 rpm. I really thought I'd been running it harder.

Impressive...I had heard of 2500 before.

There always seems to be a lot of activity on 40k+ mile 348's.

Not that I would ever want to own one, idle or not.

I call this incorrect. If you are not stressing the engine because of low speed it should last forever if maintained.

I have run outboards for 40 years and 350 hours is nothing to worry about. My new 300 xs should easily run another thousand hours with only routine maintenance. The only way that motor is hurt is either neglect or abuse!

Hours under 1000 aren't really a concern to me on any boat I have bought used. I'm more concerned with service records and receipts for work done on the motor over the hours its been in service. And I am a big proponent of warm up, especially on older carbourated stuff Drives me crazy to see guys come off the ramp and fire a motor, only to let it run for a minute and then drop the throttle. So hard on any engine when parts aren't in their happy places yet .

1230 hours on my still sealed original 500 efi!!! No top end job done yet either!

Your my hero and inspiration! I just rolled over 600 this season and trying to catch you

I know i'm playing risky a little bit, but still feel confident since it has always been run easy... Before taking them out for rebuild, i need to find a way to read them see the number of hours run in the different rpm range... And compression test before rebuilt also, just for curiosity how it still holds!!!

You are now tempting me to stick to my 300XS's...

why is that?

Couple thoughts. With such a high percentage at 800-2000, I'd bet over 99% of that 97% was at idle or no wake speed, not at the lugging RPM where you're in the middle of climbing out of the hole. There are a few idiots who plow around like that but this sounds like trolling, so very little load. Aside from maybe running rich and fouling plugs so they need replacing, is there anything else about running at idle which lessens life more than duty-cycle use? HAS to be lower stress at idle on most components, no?

Running rich will wash down cylinders wearing them out.

That is not many hours for that motor and will last a lot longer than that before it needs to be tore down.

Thanks. Is that substantially more likely to happen with carbed motors than with EFI? I'd expect fuel injection might have a better shot at keeping the mixture right at very low RPM.

Possibly yes, possibly no. A compression and leak down test will show if the rings are sealing. I would take an engine that passed both tests with low running rpm on the clock over an engine with higher recorded rpm hours.

I am jealous, just stuck a valve on one of my 525efi's with 346 hours. Looks like header failure tho. Was hoping to make 400 before top end service. NOT!

I can't believe I am saying this, but I respectfully disagree with BUP. Yes, IF an engine was run a lot near 2000 rpms and plowing through the water, then yes you are lugging the hell out if it. But, I don't see people doing that(well, once in a great while). Stock MPI marine engines may run a little rich at idle, but they're not washing down rings. So, I don't think a lot of hours in the 800-2000 rpms is a bad thing.

Now, if you hopped in the boat for a test ride and the owner was one of those people that did "plow around" at just under 2000 rpms, then I would agree. But again, I rarely see people doing that.

How about twin Mercruiser 496's with 900 hours in a 37 Formula? New motors soon? Would you buy it? Of course broker thinks it's no big deal.

Performance boats here,no.

Family boats,all the friggin time. Suks !

Ok not trying to play bad cop here but lets set the record straight

1. these are not 4 stroke motors

2 they are Optimax engines that depend on correct fuel pressure and air pressure from air injectors. One of the most important things for an opti to run.

3 Optimax's hate to troll around at low idle speeds for long periods all the time. they are plug foulers for long PERIODS of idle speeds. That alone washes down the cyc walls and or causes a lot of carbon build up.

4. The OP posted that 97 % of the run times were 2000 rpms and below --- IS THAT CORRECT ? Go ask any Opti expert that has torn these down and rebuilds them all the time. This thing could be very well carboned up like a pig. Also running an engine at one rpm always and or low rpms always does not promote good ring seal against the cyc walls.

5. How many has even worked or even changed spark plugs on a Opti up here ? If so you will and can tell some of the driving habits , trolling and low idle most of the time will be carbon / plug fouling all over the spark plugs. Not uncommon at all.

With any marine engine runs times is another way to look at when buying an boat / engine. Again look for run times 70 to 75 % of max load more so than an engine that has higher idle rpms and WOT. Of course maintenance is a huge part of it. Proper Cooling and fuel / ie rich and lean running as well important.

Not around here. I do believe you get your azz kicked for that! :)