Slow cruise problems?
- Thread starter Jake
- Start date
I guess that might depend on what engine. Might be different for a big 200 Honda vs my little 40 Yami's but I'm thinking that for the size we have on the C-Dory's (40's up to 150's? on the 25's) they should be OK. I have almost 1300 hours and I would guess that 75% of that is at slow cruise.
El and Bill on Halcyon probably never broke the planning barrier (like the sound barrier in an airplane) and they had plenty more hours than most, and all at hull speed.
Brent is right, all the systems should be operating WNL.
Harvey
SleepyC :moon
El and Bill on Halcyon probably never broke the planning barrier (like the sound barrier in an airplane) and they had plenty more hours than most, and all at hull speed.
Brent is right, all the systems should be operating WNL.
Harvey
SleepyC :moon
My Honda 150 engines are actually modified Honda Accord/CRV/Odyssey automotive engines. I suspect if you compare the average RPM at highway speeds to your Honda 150 cruising at six knots, the RPM range would be pretty much the same.
My Honda 150's have close to 2400 hours and continue to purr like kittens and will probably outlive me. If you service the motor according to the owner's manual I think you will find it a real challenge to wear a modern 4 stroke outboard 'out' regardless of whether you go-fast or putt-putt. Anecdotal evidence points to a service life of 5000 to 10000 hours in marine commercial/law enforcement work. At 55 mph, 5000 hours would equate to 275,000 miles, which is not uncommon for Honda automotive service life. I recently read where a Toyota pickup was traded in with 1,000,000 miles, and still had the original engine (youtube - meet the one million mile Toyota)
My Honda 150's have close to 2400 hours and continue to purr like kittens and will probably outlive me. If you service the motor according to the owner's manual I think you will find it a real challenge to wear a modern 4 stroke outboard 'out' regardless of whether you go-fast or putt-putt. Anecdotal evidence points to a service life of 5000 to 10000 hours in marine commercial/law enforcement work. At 55 mph, 5000 hours would equate to 275,000 miles, which is not uncommon for Honda automotive service life. I recently read where a Toyota pickup was traded in with 1,000,000 miles, and still had the original engine (youtube - meet the one million mile Toyota)
For modern 4 strokes there is no problem. If you do this, and maintain them properly they will last longer than if you run them at 4500 rpm as a rule, all other things equal.
This would not necessarily be the case with older, carburated 2 stroke motors that have issues because the oil is in the fuel and at a fixed ratio, so without building up heat you don't burn the oil off as much, leading to smoking and sputtering after awhile. Usually you run at high rpm for awhile and its ok. Some old 4 stroke motors like to be run at high rpm on occasion to "blow out the carbon" but if you have newer carbureted motors, or fuel injection, this just isn't a thing.
Some of the newer 2 strokes change the oil fuel ratio at different RPMs and this works wort of well, but have had issues running an optimax at low RPM, and had trouble with a brand new ETEC 90 at low RPM, but this was almost certainly an issue with a new boat and fuel tank ventilation, not the motor.
This would not necessarily be the case with older, carburated 2 stroke motors that have issues because the oil is in the fuel and at a fixed ratio, so without building up heat you don't burn the oil off as much, leading to smoking and sputtering after awhile. Usually you run at high rpm for awhile and its ok. Some old 4 stroke motors like to be run at high rpm on occasion to "blow out the carbon" but if you have newer carbureted motors, or fuel injection, this just isn't a thing.
Some of the newer 2 strokes change the oil fuel ratio at different RPMs and this works wort of well, but have had issues running an optimax at low RPM, and had trouble with a brand new ETEC 90 at low RPM, but this was almost certainly an issue with a new boat and fuel tank ventilation, not the motor.
BTDT":1vntzvzs said:
When I sold my 1984 Toyota Tercel 4WD Wagon it had 680,000 miles on it. Yes, with the original engine that had never been opened up and still getting 30-34 mpg. I had done water pump, radiator, alternator and start once, and brakes and batteries.
Harvey
SleepyC :moon
journey on
New member
Journey On's Honda 150 has ~1000 hrs on it, mostly at hull speed. Changed the plugs once. should change the impeller again. Changed the oil once per year, so 10 times. I'd bet that 75% has been at 2200 rpm, which is 6-7 knts. No problems yet.
Not only one sees more of the surrounding land and seascape, but the mileage goes up to 6 nmpg. I guess we're cruisers.
Boris
Not only one sees more of the surrounding land and seascape, but the mileage goes up to 6 nmpg. I guess we're cruisers.
Boris
Others know a lot more about these things than I do, and will surely correct me if I am wrong. Even thought you may be operating at slow boat and engine speed much of the time, I believe it is still important to have a prop that lets the engine run at the recommended RPM at wide open throttle.
My experience, and that of many others, has been that the newer 4-strokes do just fine operating extensively at lower RPM.
My experience, and that of many others, has been that the newer 4-strokes do just fine operating extensively at lower RPM.
El and Bill
New member
Enjoy the quiet beauty of slow cruising. Keep your heart chugging calmly along, relax the nervous system, feel the sun on your back, watch the soaring gulls, and let cares slip away. What difference does it make about fuel consumption or engine wear -- you can buy a new engine, but have you priced a new heart lately?
"The world is too much with us, late and soon.
Little we see in Nature that is ours;
We have given our hearts away, a sordid boon!
This Sea that bares her bosom to the moon;
The winds that will be howling at all hours,
And are up-gathered now like sleeping flowers;
For this, for everything, we are out of tune;
It moves us not. ."
Kick back....
"The world is too much with us, late and soon.
Little we see in Nature that is ours;
We have given our hearts away, a sordid boon!
This Sea that bares her bosom to the moon;
The winds that will be howling at all hours,
And are up-gathered now like sleeping flowers;
For this, for everything, we are out of tune;
It moves us not. ."
Kick back....
South of Heaven
New member
I personally would at least vary the RPMs from time to time. Even if only for a few minutes here and there.
El and Bill
New member
Catman --
-- what great times we have shared together. We think of those times often. Our best to you. El and Bill
-- what great times we have shared together. We think of those times often. Our best to you. El and Bill
Seems I often have to throw a wrench into a well meaning but misinformed
discussion with those relying on their "experience" to guide them, and others,
into what they feel is best for themselves which results in spreading
misinformation to others who may be unaware. This is one of those times.
Granted, it seems reasonable running your engine at low RPMs is being 'kind' to
it, helping it live a better and longer life and give you fewer and less costly repairs
if ever needed.
Wrong.
Your outboard engine is designed and developed, at minimum, to be run and
reach "operating temperature" which is well above minimum throttle and most
long extensive running at lower rpm trolling speeds.
The reason is simple. At operating temperature moisture is evaporated from
inside the engine. Don't get to this point and you have moisture trapped in your
engine. This is not good for your engine. Worse, you may not know it is even
happening. Maybe you'll get away with it for some time. Maybe you won't.
Don't take my word for this. Read your Owners Manual. Mine (2014 Honda BF90)
says:
"Operating Method
1. Running the engine below 3,000 rpm for more than 30% of the time so
the engine does not warm up. (and)
2. Frequent starting and stopping without allowing the engine to warm up.
Result
1. Water condenses in the engine and mixes with the oil, resulting in a milky
appearance.
2. Unburned fuel mixes with the oil, increasing the volume of oil.
Effect (of above)
The engine oil deteriorates, becomes less efficient as a lubricant, and causes
an engine malfunction."
Aye.
Grandma used to say, "Not caring for your equipment will cost you in the end."
discussion with those relying on their "experience" to guide them, and others,
into what they feel is best for themselves which results in spreading
misinformation to others who may be unaware. This is one of those times.
Granted, it seems reasonable running your engine at low RPMs is being 'kind' to
it, helping it live a better and longer life and give you fewer and less costly repairs
if ever needed.
Wrong.
Your outboard engine is designed and developed, at minimum, to be run and
reach "operating temperature" which is well above minimum throttle and most
long extensive running at lower rpm trolling speeds.
The reason is simple. At operating temperature moisture is evaporated from
inside the engine. Don't get to this point and you have moisture trapped in your
engine. This is not good for your engine. Worse, you may not know it is even
happening. Maybe you'll get away with it for some time. Maybe you won't.
Don't take my word for this. Read your Owners Manual. Mine (2014 Honda BF90)
says:
"Operating Method
1. Running the engine below 3,000 rpm for more than 30% of the time so
the engine does not warm up. (and)
2. Frequent starting and stopping without allowing the engine to warm up.
Result
1. Water condenses in the engine and mixes with the oil, resulting in a milky
appearance.
2. Unburned fuel mixes with the oil, increasing the volume of oil.
Effect (of above)
The engine oil deteriorates, becomes less efficient as a lubricant, and causes
an engine malfunction."
Aye.
Grandma used to say, "Not caring for your equipment will cost you in the end."
journey on
New member
Foggy, I just looked through the Honda operating manual for the 2005 150 bolted on the end of Journey On. I don't see the warning you have given, and I've never heard of it. I do agree the engine needs to be warmed up and Honda recommends that. Since there are 2 thermostats in the engine, I assumed that they would maintain a high enough temperature whatever the speed. When I change the oil, it looks clean and not diluted.
I submit that running a modern 4-stroke outboard at 2000 RPM will not hurt it.
On a diesel engine slow running at a light load creates low temperatures in the cylinders and the fuel doesn't get completely burned, thus washing down the walls and diluting the oil. The solution to that is not to idle diesel engines for longer that you have to and when they're only run at low speed (sailboats) change oil at shorter intervals. But that's only for diesels.
Boris
I submit that running a modern 4-stroke outboard at 2000 RPM will not hurt it.
On a diesel engine slow running at a light load creates low temperatures in the cylinders and the fuel doesn't get completely burned, thus washing down the walls and diluting the oil. The solution to that is not to idle diesel engines for longer that you have to and when they're only run at low speed (sailboats) change oil at shorter intervals. But that's only for diesels.
Boris
I may be misinformed, but like the OP I have automotive based four cylinder Honda 150 outboards. There is no mention of minimum 3000 rpm in the manual, and if I had to spend 30% of my time above 3000 RPM I mostly would be on plane between visits with the water police. In my area there are number of no wake areas that would keep me from operating my boat if I had to keep the RPM above 3000 rpm 30% of the time. With 2300 hours on my engines, the oil has always been clear and looking like new when I drained them.
I did find a maximum of 2000 rpm for the first hour of break-in in the owners manual but that was it. As to warm up, it states "above 41 degrees warm up the engine for al least 3 minutes".
Also, most RV generators must operate at 1800 or 3600 RPM continuous in order to maintain the North American electrical standard of 60 cycles/hertz. A number of the RV's we made were sold to NASCAR race teams that would often put 10,000 to 12,000 hours on their gensets at 1800 rpm with little or no problems. During their life the engines never varied more than 1% in RPM, and were still operating well when the coaches were traded in.
I did find a maximum of 2000 rpm for the first hour of break-in in the owners manual but that was it. As to warm up, it states "above 41 degrees warm up the engine for al least 3 minutes".
Also, most RV generators must operate at 1800 or 3600 RPM continuous in order to maintain the North American electrical standard of 60 cycles/hertz. A number of the RV's we made were sold to NASCAR race teams that would often put 10,000 to 12,000 hours on their gensets at 1800 rpm with little or no problems. During their life the engines never varied more than 1% in RPM, and were still operating well when the coaches were traded in.
Boris,
Not arguing. Just for the record.
While I appreciate your well meaning input about your 2005 Honda and what may
be lacking information in the Owners Manual, I cannot see the direct comparison
with a newer engine of almost 10 years. This suggests there has been no
improvements or changes by the same Mfg in the two engines over almost a
decade which is highly doubtful and can explain why new information has been
added to compliment a newer engine model.
As far as diesel engines creating lower cylinder temperatures during combustion
compared to gasoline, I find the opposite to be true. It is widely held that diesel
fuel is more efficient, runs leaner, has more power/stroke and has generally
double the compression ratio compared to gas engines. It is this higher
compression ratio that allows the diesel to not require a spark plug to ignite its
fuel and is responsible for the higher peak temperature in the cylinder during
ignition and power stroke than a gasoline engine.
Aye.
PS: My 2014 manual Pg. 50.
Not arguing. Just for the record.
While I appreciate your well meaning input about your 2005 Honda and what may
be lacking information in the Owners Manual, I cannot see the direct comparison
with a newer engine of almost 10 years. This suggests there has been no
improvements or changes by the same Mfg in the two engines over almost a
decade which is highly doubtful and can explain why new information has been
added to compliment a newer engine model.
As far as diesel engines creating lower cylinder temperatures during combustion
compared to gasoline, I find the opposite to be true. It is widely held that diesel
fuel is more efficient, runs leaner, has more power/stroke and has generally
double the compression ratio compared to gas engines. It is this higher
compression ratio that allows the diesel to not require a spark plug to ignite its
fuel and is responsible for the higher peak temperature in the cylinder during
ignition and power stroke than a gasoline engine.
Aye.
PS: My 2014 manual Pg. 50.
Proposed solution for outboard powered boat owners that run their larger
engines at lower RPMs most of the time to troll, sight see, comply with no wake
zones, manatee areas or just simple preference: don't run your larger engines at
lower RPMs most of the time.
Instead, run your "kicker" at higher RPMs. You may save fuel and increase the life
of your larger engine not to mention make both engines happy.
Got twin larger engines? Not as clean as above solution. Maybe if you know in
advance you will run at trolling speed most of the time, you should consider your
set up to be single engine w/kicker.
But then, in SW Florida, I see lots of fishermen with big twin or triple CC boats and
a kicker (read money is no object down there).
Aye.
Grandma used to say to me, "Foggy, don't trip getting off your soapbox."
engines at lower RPMs most of the time to troll, sight see, comply with no wake
zones, manatee areas or just simple preference: don't run your larger engines at
lower RPMs most of the time.
Instead, run your "kicker" at higher RPMs. You may save fuel and increase the life
of your larger engine not to mention make both engines happy.
Got twin larger engines? Not as clean as above solution. Maybe if you know in
advance you will run at trolling speed most of the time, you should consider your
set up to be single engine w/kicker.
But then, in SW Florida, I see lots of fishermen with big twin or triple CC boats and
a kicker (read money is no object down there).
Aye.
Grandma used to say to me, "Foggy, don't trip getting off your soapbox."
Foggy":6kg2lyar said:
The 2015 manual for the Honda 135-150 makes no mention of 3000 rpm or 30%, it simply advises to let it warm for 3 minutes.
While I may be misinformed about 'my' 2007 Honda 150 outboards, I will continue to follow my 150 owners manual versus Foggy's 90 hp manual. nuff said, and I'm going boating :thup