Hi folks, the last post got me wondering...assuming the motor is in got shape...any problems with running the average 2-stroke 6HP or so up to the 9.9HP's for a long time? I have an 88 Evinrude Yachttwin 9.9 2 stroke. Thanks in advance! Jack
Running 2-Srtokes for long periods??????
- Thread starter jackhartjr
- Start date
- Status
Mine handled it just fine
Our Nissan 5hp handled a trip from Baltimore to Solomons, MD without a problem. 13 hours on a completely wind-free summer day. I have not run it that long since then, in fact never more than 1 hour, but it's still in good shape. And it's a 20 year old motor, at that. I think with 2 strokes, the key is fresh gas and good lube oil, and they will take a fair amount of abuse.
Our Nissan 5hp handled a trip from Baltimore to Solomons, MD without a problem. 13 hours on a completely wind-free summer day. I have not run it that long since then, in fact never more than 1 hour, but it's still in good shape. And it's a 20 year old motor, at that. I think with 2 strokes, the key is fresh gas and good lube oil, and they will take a fair amount of abuse.
Not at all...
I have a Yamaha 8 hp 2 stroke,on My Freedom 25 and have run it for up to 8 hrs a day, no prob. Similarly with previous Mariner 2 stroke.
I have a Yamaha 8 hp 2 stroke,on My Freedom 25 and have run it for up to 8 hrs a day, no prob. Similarly with previous Mariner 2 stroke.
Two stroke cure
If your have a 2 or 4 stroke they will carbon up after long runs at low or med. speed. Head temp is the key, if you can hold your finger on the engine head for more than 3 seconds then it is running to cold. (less than 3 to hot) Water temp will also have some effect on head temp. The colder the engine temp the less the fuel burns cleanly and leaves carbon deposits on the head, plug and piston. Two or three cures. Change to a higher temp thermostat and hotter spark plugs. Run your engine at higher RPM to increase head temp. If your engine is getting hard to start or not running well there is a cure. Yamaha "Ring Free" added to your fuel. OMC "Engine Tunner" sprayed in to your carb while the engine is running. Both of these treatments will remove the carbon and make your engine run like it did when it was new.
If your have a 2 or 4 stroke they will carbon up after long runs at low or med. speed. Head temp is the key, if you can hold your finger on the engine head for more than 3 seconds then it is running to cold. (less than 3 to hot) Water temp will also have some effect on head temp. The colder the engine temp the less the fuel burns cleanly and leaves carbon deposits on the head, plug and piston. Two or three cures. Change to a higher temp thermostat and hotter spark plugs. Run your engine at higher RPM to increase head temp. If your engine is getting hard to start or not running well there is a cure. Yamaha "Ring Free" added to your fuel. OMC "Engine Tunner" sprayed in to your carb while the engine is running. Both of these treatments will remove the carbon and make your engine run like it did when it was new.
2 strokes
I have had Johnson/Evinrude 2 strokes on sailboats for over 25 years now, and have some experience with them. To answer your question: You can most certainly run them for long periods without problems. I have run mine for as long as 24 hours straight at nearly full throttle, and regularly run it for 7-8 hours. Backing off the throttle obviously saves fuel, but there is no harm in running them wide open. 2 stroke outboards are drastically under-stressed, and even at max rpms are well below engine speeds that could cause undue harm. The reality also is that you are never going to get max rpms when pushing a sailboat anyway. Use good quality oil and a filter in your gas line and don't worry!
I have had Johnson/Evinrude 2 strokes on sailboats for over 25 years now, and have some experience with them. To answer your question: You can most certainly run them for long periods without problems. I have run mine for as long as 24 hours straight at nearly full throttle, and regularly run it for 7-8 hours. Backing off the throttle obviously saves fuel, but there is no harm in running them wide open. 2 stroke outboards are drastically under-stressed, and even at max rpms are well below engine speeds that could cause undue harm. The reality also is that you are never going to get max rpms when pushing a sailboat anyway. Use good quality oil and a filter in your gas line and don't worry!
Me too! *bzz
My 1986 Evinrude Yachttwin 9.9 has been very reliable both for long runs (> 1 hour) and multiple short runs. No oiling up or other issues. I am in the process of pulling the head to clean out the water jacket, check thermostat etc. for a winter project as it runs in salt water and I only flush once at the end of the season. Although there is some crud in there, it's not half as bad as I had thought it would be. The thermostat was clogged, though, and the tiny hole in the head that acts as a bypass was also clogged. I might drill that out to 3/16 or so to prevent future blockage. *! If you run in silty water (that you can't see through) then I would recommend changing the impeller annually. I used mine for two seasons, and it is shot.
My 1986 Evinrude Yachttwin 9.9 has been very reliable both for long runs (> 1 hour) and multiple short runs. No oiling up or other issues. I am in the process of pulling the head to clean out the water jacket, check thermostat etc. for a winter project as it runs in salt water and I only flush once at the end of the season. Although there is some crud in there, it's not half as bad as I had thought it would be. The thermostat was clogged, though, and the tiny hole in the head that acts as a bypass was also clogged. I might drill that out to 3/16 or so to prevent future blockage. *! If you run in silty water (that you can't see through) then I would recommend changing the impeller annually. I used mine for two seasons, and it is shot.
Two stroke cure part 2
Fuel has a shelf life of 30 days. Buy your fuel in small amounts and use it up, if you arn't able to, then put the old fuel into your auto. Do not try and use last years fuel. Run engine dry (until it quits)after last use. Do not leave fuel in the carb all winter. Buy the best oil you can for your engine, some after market oil won't mix well or burn cleanly. Paying $1 more for your oil could save costly repairs or engine replacement. I have seen this happen more in the last few years because of poor fuel quality. I have been an outboard tech since the early 80's and fuel issues are the number one service problem.
Fuel has a shelf life of 30 days. Buy your fuel in small amounts and use it up, if you arn't able to, then put the old fuel into your auto. Do not try and use last years fuel. Run engine dry (until it quits)after last use. Do not leave fuel in the carb all winter. Buy the best oil you can for your engine, some after market oil won't mix well or burn cleanly. Paying $1 more for your oil could save costly repairs or engine replacement. I have seen this happen more in the last few years because of poor fuel quality. I have been an outboard tech since the early 80's and fuel issues are the number one service problem.
Motors Don't Get Tired
A motor doesn't get tired. If everything is right such as load and fuel so that it doesn't overheat or run cold it should run indefinately. A motor will run so many hours before it starts to wear out. Most marine engine trouble comes from the engine sitting around not being used. Most marine engines seem to rust out long before they wear out. But an engine doesn't know if it has been ran 10 hours a day or 1 hour for 10 days. After so many hours it will wear out.
A motor doesn't get tired. If everything is right such as load and fuel so that it doesn't overheat or run cold it should run indefinately. A motor will run so many hours before it starts to wear out. Most marine engine trouble comes from the engine sitting around not being used. Most marine engines seem to rust out long before they wear out. But an engine doesn't know if it has been ran 10 hours a day or 1 hour for 10 days. After so many hours it will wear out.
Why Suddenly Is Everyone Afraid to Run Outboards?!
Second thread on running a four or two stroke engine! Where I went to college in Florida, the Evinrude Motor Company test center was nearby. The optimum summer job was to be a test pilot one on of their many runabouts with engines as small as 2-horsepower attached to a dinghy to hundreds of horsepower on a v-hull. A buddy of mine got lucky and got the job one summer. It played havoc on his kidney's but he had twin 55 hp engines mounted on an 18 foot fiberglass v-hull and loved it. Everyday, rain or shine, wind or calm, these guys would literally run the hell out these engines with sudden stops, stalls, slow, fast, reverse, etc., you name it they abused it the best they could. At the en d of one month the engineers would tear them apart and check the wear and fatigue points, seals, power heads and all related components. Non-stop for the day they ran with only stops for gas and lunch. Up and down the ICW, St. Lucie inlet and Indian River they tortured these engines!! More often they broke the boats then the engines. By the way they all had engine cut off lanyards attached to their vests. Much like a jetski. These outboards either small, large, longshaft, shortshaft, 2-stroke or 4-stroke were meant to be run people and you can depend on an outboard tuned and well lubricated to push a sailboat at hull speed to run day and night. I would never hesitate to take a 2-stroke or 4-stoke on a long journey. Remain confident. Bob
Second thread on running a four or two stroke engine! Where I went to college in Florida, the Evinrude Motor Company test center was nearby. The optimum summer job was to be a test pilot one on of their many runabouts with engines as small as 2-horsepower attached to a dinghy to hundreds of horsepower on a v-hull. A buddy of mine got lucky and got the job one summer. It played havoc on his kidney's but he had twin 55 hp engines mounted on an 18 foot fiberglass v-hull and loved it. Everyday, rain or shine, wind or calm, these guys would literally run the hell out these engines with sudden stops, stalls, slow, fast, reverse, etc., you name it they abused it the best they could. At the en d of one month the engineers would tear them apart and check the wear and fatigue points, seals, power heads and all related components. Non-stop for the day they ran with only stops for gas and lunch. Up and down the ICW, St. Lucie inlet and Indian River they tortured these engines!! More often they broke the boats then the engines. By the way they all had engine cut off lanyards attached to their vests. Much like a jetski. These outboards either small, large, longshaft, shortshaft, 2-stroke or 4-stroke were meant to be run people and you can depend on an outboard tuned and well lubricated to push a sailboat at hull speed to run day and night. I would never hesitate to take a 2-stroke or 4-stoke on a long journey. Remain confident. Bob
The only way
About the only way to hurt a small outboard by running it full throttle for long periods of time, is if it is propped wrong. Propped so they can turn up full RPM at wide open throttle, without over revving, any outboard should give many, many years of good service. The most damaging situation is an over propped motor, that can't turn up full RPM and running it full throttle for extended periods.
About the only way to hurt a small outboard by running it full throttle for long periods of time, is if it is propped wrong. Propped so they can turn up full RPM at wide open throttle, without over revving, any outboard should give many, many years of good service. The most damaging situation is an over propped motor, that can't turn up full RPM and running it full throttle for extended periods.
the silent killer
this is all in my opinion, but the biggest source of internal wear is overheating, with a distant second of extended idle with the accompanied lower oil suppy. Over-revving is a given for the "catastrophic" failure (con-rods, valvetrain if you have it). Point is - I agree with Bob. If you've got oil and water pressure, you are in the RPM range, and there arent any existing conditions, you engine will run until some fuel line starts sucking air, cooling intake gets clogged, or the oil leaks/burns away (in order of easiness to correct) A motor that burns oil is not a bad motor, or an inefficient motor! It just has extra lubrication on the cylinder walls ; )
this is all in my opinion, but the biggest source of internal wear is overheating, with a distant second of extended idle with the accompanied lower oil suppy. Over-revving is a given for the "catastrophic" failure (con-rods, valvetrain if you have it). Point is - I agree with Bob. If you've got oil and water pressure, you are in the RPM range, and there arent any existing conditions, you engine will run until some fuel line starts sucking air, cooling intake gets clogged, or the oil leaks/burns away (in order of easiness to correct) A motor that burns oil is not a bad motor, or an inefficient motor! It just has extra lubrication on the cylinder walls ; )
It's an ENGINE and it doesn't care!
The best thing you can do for your engine is RUN it. The worst thing you can do to your engine is start it. (That's when the greatest wear occurs.)If you let it run without stopping it would run for more hours than you are capable of counting. Unless you are an EXPERT, DO NOT screw with thermostat temperatures and especialy with spark plug temperatures. If you question what a spark plug temperature is YOU ARE NOT KNOWLEGABLE ENOUGH TO SCREW WITH IT. Do you know how to read a spark plug? If not you must make sure your towing insurance is paid in full. You want to burn holes in your pistons? Go ahead and play with spark plug heat ranges. The manufacturers put a lot of time and money into the design of their products. While I've seen it on rare occasion they are seldom wrong these days when it comes to spark plugs.
The best thing you can do for your engine is RUN it. The worst thing you can do to your engine is start it. (That's when the greatest wear occurs.)If you let it run without stopping it would run for more hours than you are capable of counting. Unless you are an EXPERT, DO NOT screw with thermostat temperatures and especialy with spark plug temperatures. If you question what a spark plug temperature is YOU ARE NOT KNOWLEGABLE ENOUGH TO SCREW WITH IT. Do you know how to read a spark plug? If not you must make sure your towing insurance is paid in full. You want to burn holes in your pistons? Go ahead and play with spark plug heat ranges. The manufacturers put a lot of time and money into the design of their products. While I've seen it on rare occasion they are seldom wrong these days when it comes to spark plugs.
If i read the post correctly
john suggests that for people who don't use full throttle, it is helpful to make the engine run hotter. On the thermostat issue - I question why a hotter thermostat will change part-throttle anything, if the engine is colder than thermostat temp to begin with. As for spark plugs - It sounds like you are telling me to put hot plugs in before an extended mid-rpm cruise, and switch back to the cold ones for short time usage?
john suggests that for people who don't use full throttle, it is helpful to make the engine run hotter. On the thermostat issue - I question why a hotter thermostat will change part-throttle anything, if the engine is colder than thermostat temp to begin with. As for spark plugs - It sounds like you are telling me to put hot plugs in before an extended mid-rpm cruise, and switch back to the cold ones for short time usage?
Hotter Plugs if Fouled
If your plugs are fouling with oil you need to use less oil or a hotter plug. Assuming that you are using the correct amount of oil a hotter plug is the only choice. A hotter plug just means that the electrode is hotter it doesn't make bigger sparks or make the engine run hotter. The down side of a too hot plug is that the electrode will erode away more quickly. A common cause of fouled plugs is that the engine isn't ran long enough to warm up enough to run well or the engine is ran a lot in cold weather. My Tohatsu 3.5 runs smokey and poorly until it gets warm and then it runs just fine. But in the winter it takes longer to get warm. If I was using it just to get into and out of a slip it would never get warm enough to run well and would have fouled plugs. As it is every time I use the engine I run it for several minutes WOT to make sure that the engine gets hot enough to run well and burn off any deposits. The thermostat only works when the engine can get hot enough to open the thermostat. So with a 160 thermostat the thermostat never opens if the engine only gets to 150. As noted in this situation using a 180 thermostat won't help. Some smaller outboards don't even use thermostats. The whole thing about running hot or cold is that the fuel won't properly vaporise at low temperatures and if the engine is too hot the fuel can detonate prematurely messing up the engine's timing.
If your plugs are fouling with oil you need to use less oil or a hotter plug. Assuming that you are using the correct amount of oil a hotter plug is the only choice. A hotter plug just means that the electrode is hotter it doesn't make bigger sparks or make the engine run hotter. The down side of a too hot plug is that the electrode will erode away more quickly. A common cause of fouled plugs is that the engine isn't ran long enough to warm up enough to run well or the engine is ran a lot in cold weather. My Tohatsu 3.5 runs smokey and poorly until it gets warm and then it runs just fine. But in the winter it takes longer to get warm. If I was using it just to get into and out of a slip it would never get warm enough to run well and would have fouled plugs. As it is every time I use the engine I run it for several minutes WOT to make sure that the engine gets hot enough to run well and burn off any deposits. The thermostat only works when the engine can get hot enough to open the thermostat. So with a 160 thermostat the thermostat never opens if the engine only gets to 150. As noted in this situation using a 180 thermostat won't help. Some smaller outboards don't even use thermostats. The whole thing about running hot or cold is that the fuel won't properly vaporise at low temperatures and if the engine is too hot the fuel can detonate prematurely messing up the engine's timing.
old 2 stroke
Ive got an 88 2 stroke 8hp mercury. It came with the boat when I bought it in 2000. I usually sail off a mooring and back on. I dont get to run the motor much I buy 9 gals of gas enough to fill my 6 and 3 gal tanks on May 15 when I put the boat in and I usually have a gallon or 2 left on Oct 15 when I haul it. Short sailing season on MA bay. I dont abuse the motor or run It hard I only use it when Im out of wind. The service guy tells me Im not running it enough. But so far I havent had ANY TROUBLE. I know something about sailing but not much about motors. Am I doing something wrong? abuse the motor
Ive got an 88 2 stroke 8hp mercury. It came with the boat when I bought it in 2000. I usually sail off a mooring and back on. I dont get to run the motor much I buy 9 gals of gas enough to fill my 6 and 3 gal tanks on May 15 when I put the boat in and I usually have a gallon or 2 left on Oct 15 when I haul it. Short sailing season on MA bay. I dont abuse the motor or run It hard I only use it when Im out of wind. The service guy tells me Im not running it enough. But so far I havent had ANY TROUBLE. I know something about sailing but not much about motors. Am I doing something wrong? abuse the motor
bffatcat
Running 7 gallons of fuel in a small outboard in a season isn't bad. Alot of fishing boats have small kicker motors and don't burn much more fuel than that! The only thing I would make sure I did was use stabil or similar in the fuel to keep it fresh as possible. Brian
Running 7 gallons of fuel in a small outboard in a season isn't bad. Alot of fishing boats have small kicker motors and don't burn much more fuel than that! The only thing I would make sure I did was use stabil or similar in the fuel to keep it fresh as possible. Brian
- Status