Outboard engine "hours" question

[Buzzy]

I'm in the market to buy a boat - something to use in my part of the world; lakes, reservoirs on the Columbia and the Hanford Reach. I want a four-stroke capable of pushing a 16'-17' boat upstream in The Reach. Power trim/tilt, electric start mandatory and more than likely a used boat/motor. I found a boat on Craigslist that fits some of the check marks (https://kpr.craigslist.org/boa/d/kennewick-2017-rh-pro-v16/7817069197.html). The ad lists the motor at 300 hours (with claims to be serviced annually).

Question: Is there any rule of thumb, any guide, any data..... that suggests how many hours one of these motors will run (properly maintained). What's the "life" of a modern 4-stroke motor in terms of engine hours? Is there any way to tell if the used (boat) motor I'm looking at is close to its end of life function?

I realize buying a used (boat) motor is probably akin to buying a used car without a warranty. (For that matter I once bought a new "car" that was a piece of junk from day one.)

 

[Evan B]

I bought two new Suzukis last year: a 200hp and a 60hp. Each got a bit over 100hrs in their first year. 300hrs is in the "just broke in" bracket

Merc is a brand I personally don't seek out, but all modern outboards are good in their own way. Mercs tend to be the higher performance at the expense of reliability one (for the most part). But many end up having great luck with them. I just know a lot of guys down in my neighborhood who have sworn them off for good.

All that said, chances of you still enjoying the hell out of a package like that is still extremely high.

 

[skyriver]

As you know Pat, I've been looking as well. I want one with a windshield so I won't low-hole you on this one.
300 hours is perfect in my opinion. Like Evan says, the guy has broke it in for you.
The internet tells me modern 4-strokes should have 4000-5000 hours possible if properly maintained.

That's a very nice package. Seems he's taken very good care of it.
My experience is limited to 2-stroke Mercs, but I've never had one let me down.

If it checks most of your boxes I'd pull the trigger!

 

[SurfnFish]

That 40 Merc is likely a rebadged Tohatsu, who produces Merc's 40hp and under with a few exceptions. A well maintained and properly sized four stroke in that class should easily go 4000 hrs - sizing being the problem in this case.
I've owned several 16' tin skiffs and found 40hp to be barely sufficient power, much preferring 60 HP for all around power, acceleration and cruising.
That model RH has a beam of 88" with a bare hull weight over 550#. Add in a couple of men, full fuel tank, gear and accessories, and 40hp is not going to push 1000# without the engine being maxed most of the time = shorter working life.
Regardless, when you do find the boat you want, as part of the deal have the motor scanned by an outboard tech which should give you the confidence to know if you're buying a well maintained motor with zero issues.

 

[Evan B]

That 40 Merc is likely a rebadged Tohatsu, who produces Merc's 40hp and under with a few exceptions. A well maintained and properly sized four stroke in that class should easily go 4000 hrs - sizing being the problem in this case.
I've owned several 16' tin skiffs and found 40hp to be barely sufficient power, much preferring 60 HP for all around power, acceleration and cruising.
That model RH has a beam of 88" with a bare hull weight over 550#. Add in a couple of men, full fuel tank, gear and accessories, and 40hp is not going to push 1000# without the engine being maxed most of the time = shorter working life.
Regardless, when you do find the boat you want, as part of the deal have the motor scanned by an outboard tech which should give you the confidence to know if you're buying a well maintained motor with zero issues.

Tohatsu is 30hp and under. I believe the 40-60hp are actually built as a Mercury with Mercury parts, but in China.

I'll agree on the size, too. I have a very lightweight, barebones aluminum 16' boat and after one season, sold the 40hp Merc on it to get the 60hp Suzuki. Much better fit. 40-60hp tend to be the same engine with most brands, but the 60hp will be the tuned version to get the max horsepower from the same block. It'll be similar in the lower RPMS, but once you get in to the mid to upper RPMs, you'll see the difference.

 

[Chucker]

There seem to be a lot of things that cause the death of outboards. The use hours are only one of them. One of those Mercs should last 20 years+ and get at least 2000 hours (I have one, and that’s where it is at), but realistically the average that outboards last in the US is something less than 700 hours. The main reason for that seems to be that they sit around, not getting used. I think that’s especially an issue for motors used in saltwater. It’s corrosive stuff if it has time to work on something.

An old bloke who knows motors told me that the best plan to get a long life out of an outboard was to do the scheduled oil changes and run the thing as often as possible. That’s not an issue in the summer, but I do have to make an effort to get it out once a month or so during ski season.

For that particular motor, it has an internal hour meter, but no gauge as standard. You can get it scanned by a dealer, or you can install one of these

VesselView Mobile

www.mercurymarine.com

It’s a unit that plugs into the wiring harness and sends all the data that is being collected to your phone. Totally worth the $150 that it costs.

Also. Don’t trust an hour estimate from the seller. They are usually wildly off. The guy I bought my boat from said it had “about a thousand hours” and we agreed a price accordingly. The actual - 253.

 

[Evan B]

There seem to be a lot of things that cause the death of outboards. The use hours are only one of them. One of those Mercs should last 20 years+ and get at least 2000 hours (I have one, and that’s where it is at), but realistically the average that outboards last in the US is something less than 700 hours. The main reason for that seems to be that they sit around, not getting used. I think that’s especially an issue for motors used in saltwater. It’s corrosive stuff if it has time to work on something.

An old bloke who knows motors told me that the best plan to get a long life out of an outboard was to do the scheduled oil changes and run the thing as often as possible. That’s not an issue in the summer, but I do have to make an effort to get it out once a month or so during ski season.

For that particular motor, it has an internal hour meter, but no gauge as standard. You can get it scanned by a dealer, or you can install one of these

VesselView Mobile

www.mercurymarine.com

It’s a unit that plugs into the wiring harness and sends all the data that is being collected to your phone. Totally worth the $150 that it costs.

Also. Don’t trust an hour estimate from the seller. They are usually wildly off. The guy I bought my boat from said it had “about a thousand hours” and we agreed a price accordingly. The actual - 253.

another thing with most outboards: If it's hooked up to a tach (which all outboards should IMO so you know you're propped right), even if it doesn't have an hours meter, you can tell another way. When you turn the key on and get the beep, the tach will swing up to a number. That will be your hours. So if it swings up to 3 then back down, you have 300hrs.

this has been the case for my Suzukis and Hondas, but I honestly don't know about Mercs.

 

[Chucker]

That 40 Merc is likely a rebadged Tohatsu, who produces Merc's 40hp and under with a few exceptions. A well maintained and properly sized four stroke in that class should easily go 4000 hrs - sizing being the problem in this case.
I've owned several 16' tin skiffs and found 40hp to be barely sufficient power, much preferring 60 HP for all around power, acceleration and cruising.
That model RH has a beam of 88" with a bare hull weight over 550#. Add in a couple of men, full fuel tank, gear and accessories, and 40hp is not going to push 1000# without the engine being maxed most of the time = shorter working life.
Regardless, when you do find the boat you want, as part of the deal have the motor scanned by an outboard tech which should give you the confidence to know if you're buying a well maintained motor with zero issues.

One of those engines pushes my 600# boston whaler fully loaded at 23 knots at 4200 rpm. So it’s not fast, but it’s cruising comfortably and not maxed out. Those motors are designed to be run at high rpms anyway. If you are willing to sacrifice a bit of top speed for the low fuel consumption you get, then it might be an appropriate size motor for that boat for you.

 

[Chucker]

another thing with most outboards: If it's hooked up to a tach (which all outboards should IMO so you know you're propped right), even if it doesn't have an hours meter, you can tell another way. When you turn the key on and get the beep, the tach will swing up to a number. That will be your hours. So if it swings up to 3 then back down, you have 300hrs.

this has been the case for my Suzukis and Hondas, but I honestly don't know about Mercs.

I didn’t know that. I will have to go and check if it is true for the Merc…

Update: No. At least not for my motor. It sits at the idle speed that it was at when it was shut off, and just drops to zero when turned on.

 

[krusty]

There seem to be a lot of things that cause the death of outboards. The use hours are only one of them. One of those Mercs should last 20 years+ and get at least 2000 hours (I have one, and that’s where it is at), but realistically the average that outboards last in the US is something less than 700 hours. The main reason for that seems to be that they sit around, not getting used. I think that’s especially an issue for motors used in saltwater. It’s corrosive stuff if it has time to work on something.

An old bloke who knows motors told me that the best plan to get a long life out of an outboard was to do the scheduled oil changes and run the thing as often as possible. That’s not an issue in the summer, but I do have to make an effort to get it out once a month or so during ski season.

For that particular motor, it has an internal hour meter, but no gauge as standard. You can get it scanned by a dealer, or you can install one of these

VesselView Mobile

www.mercurymarine.com

It’s a unit that plugs into the wiring harness and sends all the data that is being collected to your phone. Totally worth the $150 that it costs.

Also. Don’t trust an hour estimate from the seller. They are usually wildly off. The guy I bought my boat from said it had “about a thousand hours” and we agreed a price accordingly. The actual - 253.

Nothing with an ICE gets better sitting around unused.

I couldn't tell you how many times I've been aboard a seldom used motorboat...inboard or outboard...that breaks down on one of its rare outings. Hell...once got stranded on a canoe camping trip to the Upper Priest Lake with a pristine looking little outboard (that had sat unused in a garage for years) somebody loaned me. Ran like a top...on the way up.

Conversely...a friend who lives on an island across the harbor from Sitka has had very few engine problems (despite constant exposure to a tough marine environment) with either of his two boats because they are in very frequent use.

This is, of course, why grandma's 20 year old low mileage 'creampuff' car is very often a mechanical headache.

 

[Rob Allen]

Old motor with lower hours can be bad because one of the big outboard killers is sitting idle for long periods of time.
1. Compression check.. know what the Compression should be and check it.
2. Check the magnet on the lower unit drain. Fine metal fibers are fine chunks of metal not good.

I'm sure there a lot of other things and there are probably tons of you tube videos
But those are the two big things I know.

Ohh and hp wise? Always max out your hull if you can.

 

[Guy Gregory]

another thing with most outboards: If it's hooked up to a tach (which all outboards should IMO so you know you're propped right), even if it doesn't have an hours meter, you can tell another way. When you turn the key on and get the beep, the tach will swing up to a number. That will be your hours. So if it swings up to 3 then back down, you have 300hrs.

this has been the case for my Suzukis and Hondas, but I honestly don't know about Mercs.

Wow, I hope this works for my 03 Yamaha...It's got a recently installed hour meter, but that's basically telling me what time the barn door was closed.

My Yamaha purchased used last year pushes my 900 lb. Lowe Sea Nymph at about 25 mph (according to the speedo) at 4500. I'll have better info this year now I've got a gps installed. I'm hoping it'll get Seaton's to Rufus and back without too much trouble.

That RH is a great hull, I'm envious, I hope it works out for ya...

 

[Evan B]

I didn't look online very hard, but here's what I'm talking about:

 

[dep]

another thing with most outboards: If it's hooked up to a tach (which all outboards should IMO so you know you're propped right), even if it doesn't have an hours meter, you can tell another way. When you turn the key on and get the beep, the tach will swing up to a number. That will be your hours. So if it swings up to 3 then back down, you have 300hrs.

this has been the case for my Suzukis and Hondas, but I honestly don't know about Mercs.

thanks for this tip Evan. I hope this works for my Suzuki 140 two stroke. which I estimate I have put over 1000 hours on it.

I will be in the market this spring for a boat as well:
18-20 foot, aluminum hull, windshield, outboard (min 150 hp) and kicker.

gonna be selling a 2004 Larson open bow fiberglass boat with 140 hp Suzuki.

 

[Merle]

That's a cool boat Pat... I hope you get it!

 

[SurfnFish]

Tohatsu is 30hp and under. I believe the 40-60hp are actually built as a Mercury with Mercury parts, but in China.

I'll agree on the size, too. I have a very lightweight, barebones aluminum 16' boat and after one season, sold the 40hp Merc on it to get the 60hp Suzuki. Much better fit. 40-60hp tend to be the same engine with most brands, but the 60hp will be the tuned version to get the max horsepower from the same block. It'll be similar in the lower RPMS, but once you get in to the mid to upper RPMs, you'll see the difference.

have owned two 40 hp "Merc's", both built by....Tohatsu manufactures the majority of Mercury outboard engines that are 40 horsepower and under, essentially meaning that many smaller Mercury outboards are rebranded Tohatsu engines produced in a partnership between the two companies; this includes most of the Mercury 40hp and below models

 

[Evan B]

have owned two 40 hp "Merc's", both built by....Tohatsu manufactures the majority of Mercury outboard engines that are 40 horsepower and under, essentially meaning that many smaller Mercury outboards are rebranded Tohatsu engines produced in a partnership between the two companies; this includes most of the Mercury 40hp and below models

Hmm, what years are your Mercs? Because all info I've ever been able to find says it's all 30hp and under. I had a 40hp Merc from 2004 that was actually built by Yamaha (there was a transition with Yamaha while Merc was getting on board the 4 stroke bandwagon). And I know about the Tohatsu deal, but could only ever find info on 30hp and under as the 40hp-60hp is a single platform (all use the same block).

Summary from a few sources I can find online:

• Smaller Mercury outboards (30hp and below): Manufactured by Tohatsu in Japan.
• Mercury 40-60hp four-strokes: Designed and engineered by Mercury Marine, assembled in China.

There were never 40hp four-stroke Mercury outboards built by Tohatsu. The relationship between the two companies is primarily limited to the smaller horsepower range.

 

[Brute]

For salt water, I've owned multiple sets of twin Yamaha outboards from twin 50's to twin 250's...they have all worked well and relatively problem free...obviously oil and filter changes at the required interval, lower unit oil changes and impellers will usually give you longevity.

I now have a freshwater lake boat (Boston Whaler 27' Vantage) with twin 300 Merc Verado's...and have never owned Merc's before...and have owned this boat since 2018...never had a single engine problem...

 

[SurfnFish]

One of those engines pushes my 600# boston whaler fully loaded at 23 knots at 4200 rpm. So it’s not fast, but it’s cruising comfortably and not maxed out. Those motors are designed to be run at high rpms anyway. If you are willing to sacrifice a bit of top speed for the low fuel consumption you get, then it might be an appropriate size motor for that boat for you.

Sounds like your boat is dialed exactly where you want it.
I ran a 40 Merc/Tohatsu 4St on my custom tidewater 15' prop (guard cage) sled, similar weight of your whaler, and had it propped for grunt as I sometimes ran miles upriver and back, often against current. Anything over 4000 RPM was just a waste of gas with little gained speed. The guy I sold it to, however, intended long runs on the Willamette so had it re-propped for max speed at higher RPM. A decade of those runs eventually wore the engine out so he re-powered with a 60hp, the max plate rating.
Have owned a half dozen skiffs 13' to 21', powered by Merc, Tohatsu and Yamaha, 10 hp to 90hp, always comes down to horses for courses and personal comfort zone

 

[SurfnFish]

Hmm, what years are your Mercs? Because all info I've ever been able to find says it's all 30hp and under. I had a 40hp Merc from 2004 that was actually built by Yamaha (there was a transition with Yamaha while Merc was getting on board the 4 stroke bandwagon). And I know about the Tohatsu deal, but could only ever find info on 30hp and under as the 40hp-60hp is a single platform (all use the same block).

Summary from a few sources I can find online:

• Smaller Mercury outboards (30hp and below): Manufactured by Tohatsu in Japan.interesting smorgasbord
• Mercury 40-60hp four-strokes: Designed and engineered by Mercury Marine, assembled in China.

There were never 40hp four-stroke Mercury outboards built by Tohatsu. The relationship between the two companies is primarily limited to the smaller horsepower range.

The one I bought new was a 40hp Merc from Stevens marine for my little sled in 2007, the service manager explained to me it was Tohatsu built. I see a lot on their various motors online, was told by the Prop Shop no one has a bigger array of models out there than Tohatsu due to all their licensing agreements. And still find this:

Tohatsu has been manufacturing 40hp motors for Mercury throughout much of its partnership with Brunswick Corporation (the parent company of Mercury Marine), which began in 1988, meaning that many Mercury 40hp motors in recent years are essentially rebadged Tohatsu engines; most notably, smaller Mercury outboards, including the 40hp, are rebranded Tohatsu models.