I need to replace my Evinrude 9.9hp which I think is the original with the boat 1982. I have been advised that a pull-start 5hp Honda 4 stroke longshaft will have the power for the job. It's also a dramatically lighter engine than the evinrude. Any experiences/thought on this? Thank you, Mike
- Status
It all depends ....
It all depends on your power demands. Remember Horsepower is Horsepower, regardless of how it is delivered, ie; 4 vs 2 stroke. Only difference is where the power is when measured. Four stroke horsepower is more linear in respect to the power curve, while on the other hand, Two stroke tend to have a more algorythmic curve. What it boils down to is, two-strokes have a better low-end torque (power) than four-stroke motors. Put to the test, a two-stroke is faster coming out of the starting gate than a four-stroke (hole-shot) ability in other words. But it is more likely the four-stroke will catch up and pass on the high-end as the two-stroke begins to reach top rpm and flatten out. When you stop to consider what your cruising habits are, the picture becomes more clearer. If you are lake sailing and have to muscle through an occasional storm, than a lower powered four-stroke is fine for the job. On the other hand if you are coastal cruising bay and sea, island currents and tides may be an issue with a lower horse power model. Here is where, having a 9.9 comes in handy. A steeper pitched prop can be used on a two-stroke engine of the same horsepower rating over the four-stroke and thus better pulling power is accomplished as well. It may seem biased to you to think I favor two-stroke engines. Don't get that idea. Just because I own both an evinrude yachtwin 9.9 hp two-stroke on my MAC25. And I have a 50 hp evinrude E Tec on my MAC26M doesn't mean I am biased. Oh yeah, did I mention my Ford F150 pickup truck? It too is powered by a two-stroke engine. And no, I wouldn't lie to you either.
Fair winds to ya, Tommy TwoStroke.
It all depends on your power demands. Remember Horsepower is Horsepower, regardless of how it is delivered, ie; 4 vs 2 stroke. Only difference is where the power is when measured. Four stroke horsepower is more linear in respect to the power curve, while on the other hand, Two stroke tend to have a more algorythmic curve. What it boils down to is, two-strokes have a better low-end torque (power) than four-stroke motors. Put to the test, a two-stroke is faster coming out of the starting gate than a four-stroke (hole-shot) ability in other words. But it is more likely the four-stroke will catch up and pass on the high-end as the two-stroke begins to reach top rpm and flatten out. When you stop to consider what your cruising habits are, the picture becomes more clearer. If you are lake sailing and have to muscle through an occasional storm, than a lower powered four-stroke is fine for the job. On the other hand if you are coastal cruising bay and sea, island currents and tides may be an issue with a lower horse power model. Here is where, having a 9.9 comes in handy. A steeper pitched prop can be used on a two-stroke engine of the same horsepower rating over the four-stroke and thus better pulling power is accomplished as well. It may seem biased to you to think I favor two-stroke engines. Don't get that idea. Just because I own both an evinrude yachtwin 9.9 hp two-stroke on my MAC25. And I have a 50 hp evinrude E Tec on my MAC26M doesn't mean I am biased. Oh yeah, did I mention my Ford F150 pickup truck? It too is powered by a two-stroke engine. And no, I wouldn't lie to you either.
Fair winds to ya, Tommy TwoStroke.2 cycle 4cycle
Tommy, your post is exactly backward. 4cycles have the torque, 2 cycles such as dirt bikes, derive their horsepower from high revs.
Tommy, your post is exactly backward. 4cycles have the torque, 2 cycles such as dirt bikes, derive their horsepower from high revs.
2vs4
2 stroke engines will weigh less than 4 stroke engines of the same HP. 4 strokes can run at idel longer before fouling their plugs, so a larger 4 stroke can be used than a 2 stroke, as running a 2 stroke at les than half throttle for long periodss will foul the plugs. BUT 2 strokes can be operated at full throttle longer than 4 strokes. 2 cycle engines love this kind of running, 4 strokes prefer running at about 3/4 throttle, with full throttle use for only a few minutes. There are no new 2 stroke small engines being made now, so if you want a 2 stroke you will be looking at used engines. 2 strokes cost less, even when they were new. 2 stroke engines have fewer moving parts to break. 4 stroke engines tend to be quieter. If you want a new engine, you will be getting a 4 stroke. I have used a 4hp 4 stroke on a Vn23 and that was enough power. You can go up to about 6hp with out getting much heavier. Remember, weight on the transome will reduce your sailing performance. Get the longest shaft you can, small boats are prone to hobbyhorsing in the waves. If the prop is out of the water, it doesn't matter how much HP you have. A charging circuit can be had on motors as small as 5hp. Good idea for your batteries. Electric start usually starts on the 8hp and up motors. For a sail boat kicker for boats under 27 feet I think the Tohatsu 6hp extra long shaft is the best. Tohatsu makes the small motors for Merc., and Nissan, they are the same motor. So save money and get the Tohatsu. Unless it's worth it to you to have a different color or decal on the motor. Long shaft and extra long shaft motors tend to already come with a lower pitched prop. This is what you want on a kicker, thrust not speed. Short shaft motors tend to come with a higher pitched prop, for small row boats, dinghys, etc. that don't weigh as much, and want speed. If you get a small short shaft, be ready to change the prop to a lower pitch to get any performance out of it. Lower pitched props have less prop walk when put into reverse too. This is a real help when docking. A 4hp with a low pitched prop can move your boat better than a 10hp motor with a prop pitched too high. Look for a 3-4 bladed, large blades, prop made for thrust, not a small prop, small blades, high pitched, fast prop. with 2 blades for speed. A trolling motor will move your boat, but 80 lbs thrust electric motor is about equal to 1hp gas motor. A 1.5 gas out board with the right prop will push your boat anywhere, but since the loss of the British Seagull motor, no-one has made a really good 4-5 bladed high thrust prop for motors this small. Best to think of motors under 4hp as dinghy motors now. Remember that the OEM motor bracket was made for upto 10hp 2 cycle engines, not 4 cycle. If you go for a 9.9 4 cycle engine you will be getting a new motor mount too. The OEM mount does seem to handle a 6hp 4 cycle fine. I don't know anyone who wasn't happy with the 6hp extra long shaft Tohatsu. So for a new motor that would be my choice. As for 2 cycle engines, the Johnson's were the best, but as of now you will have to do some shopping to find one, and will pay a premium for it too. Sure wish I had bought more of them when you could pick them up for $200. Now they can go for as much as a new 5hp 4 cycle. Johnson, Evenrude, Merc., all made good 2 cycle engines. Merc is the maker of Mariner so it's a good engine too. Stay away from the Force engines, they had a lot of problems. No name engines and off brands can be good, but hard to find parts for now. Prop and shaft length should be of more concern than HP, as long as you are over 4hp. You are only going to do hull speed no matter what kicker you put on. PS I have pulled a Mac25 behind my Vn23 using my 6hp at 5 knots, and was not at full throttle, 6hp is plenty, just have the right prop.
2 stroke engines will weigh less than 4 stroke engines of the same HP. 4 strokes can run at idel longer before fouling their plugs, so a larger 4 stroke can be used than a 2 stroke, as running a 2 stroke at les than half throttle for long periodss will foul the plugs. BUT 2 strokes can be operated at full throttle longer than 4 strokes. 2 cycle engines love this kind of running, 4 strokes prefer running at about 3/4 throttle, with full throttle use for only a few minutes. There are no new 2 stroke small engines being made now, so if you want a 2 stroke you will be looking at used engines. 2 strokes cost less, even when they were new. 2 stroke engines have fewer moving parts to break. 4 stroke engines tend to be quieter. If you want a new engine, you will be getting a 4 stroke. I have used a 4hp 4 stroke on a Vn23 and that was enough power. You can go up to about 6hp with out getting much heavier. Remember, weight on the transome will reduce your sailing performance. Get the longest shaft you can, small boats are prone to hobbyhorsing in the waves. If the prop is out of the water, it doesn't matter how much HP you have. A charging circuit can be had on motors as small as 5hp. Good idea for your batteries. Electric start usually starts on the 8hp and up motors. For a sail boat kicker for boats under 27 feet I think the Tohatsu 6hp extra long shaft is the best. Tohatsu makes the small motors for Merc., and Nissan, they are the same motor. So save money and get the Tohatsu. Unless it's worth it to you to have a different color or decal on the motor. Long shaft and extra long shaft motors tend to already come with a lower pitched prop. This is what you want on a kicker, thrust not speed. Short shaft motors tend to come with a higher pitched prop, for small row boats, dinghys, etc. that don't weigh as much, and want speed. If you get a small short shaft, be ready to change the prop to a lower pitch to get any performance out of it. Lower pitched props have less prop walk when put into reverse too. This is a real help when docking. A 4hp with a low pitched prop can move your boat better than a 10hp motor with a prop pitched too high. Look for a 3-4 bladed, large blades, prop made for thrust, not a small prop, small blades, high pitched, fast prop. with 2 blades for speed. A trolling motor will move your boat, but 80 lbs thrust electric motor is about equal to 1hp gas motor. A 1.5 gas out board with the right prop will push your boat anywhere, but since the loss of the British Seagull motor, no-one has made a really good 4-5 bladed high thrust prop for motors this small. Best to think of motors under 4hp as dinghy motors now. Remember that the OEM motor bracket was made for upto 10hp 2 cycle engines, not 4 cycle. If you go for a 9.9 4 cycle engine you will be getting a new motor mount too. The OEM mount does seem to handle a 6hp 4 cycle fine. I don't know anyone who wasn't happy with the 6hp extra long shaft Tohatsu. So for a new motor that would be my choice. As for 2 cycle engines, the Johnson's were the best, but as of now you will have to do some shopping to find one, and will pay a premium for it too. Sure wish I had bought more of them when you could pick them up for $200. Now they can go for as much as a new 5hp 4 cycle. Johnson, Evenrude, Merc., all made good 2 cycle engines. Merc is the maker of Mariner so it's a good engine too. Stay away from the Force engines, they had a lot of problems. No name engines and off brands can be good, but hard to find parts for now. Prop and shaft length should be of more concern than HP, as long as you are over 4hp. You are only going to do hull speed no matter what kicker you put on. PS I have pulled a Mac25 behind my Vn23 using my 6hp at 5 knots, and was not at full throttle, 6hp is plenty, just have the right prop.
Your best bet
I have Touhatsu 8 which is quite small and fits into the mounting area very well. This older carb model is very forgiving to bad gas and long exposure. Because it is so simple, and perhaps less sophisticated, I find it the best I have ever had. It has a starter and each year starts in 2 seconds, even from a winter layover. My yard tells me they never have any repair issues with this motor, even w/the carbs, which with today's bad gas, is a real plus. You can find these cheap on the web. I strongly recommend you consider this motor. Also, it's gph is quite good too.
I have Touhatsu 8 which is quite small and fits into the mounting area very well. This older carb model is very forgiving to bad gas and long exposure. Because it is so simple, and perhaps less sophisticated, I find it the best I have ever had. It has a starter and each year starts in 2 seconds, even from a winter layover. My yard tells me they never have any repair issues with this motor, even w/the carbs, which with today's bad gas, is a real plus. You can find these cheap on the web. I strongly recommend you consider this motor. Also, it's gph is quite good too.
Apples to Oranges ....
When it comes to the end application, one should always consider the differences only applying to that application sense. Like I said before, I own quite a number of 2 stroke engines. From weed whackers to trucks, they have 2 stroke engines in them. My wife's Vanden Plas has an inline 6 (XJ6) 4 stroke gas engine which is the exception to what I own. None of the above can be compared to that of an outboard, be it 4 or 2 stroke. I did not mean to imply that a weed whacker motor had its torque range higher and hence was true to the proclivities defining what a 2 stroke is all about. Never let it be heard from me! Mel, you are only half right. Right in the application sense, but sadly this is more about marine outboards (2 strokers) than Ducati dirt bikes. I could argue the point that my 453 Detroit Diesel is a 2 stroke and its rated output is 495 ft lbs torque at the low end. Also I could argue that my 2 stroke Detroit is warrantied for only 2.8k RPM top end! *yks Ya gotta wonder where that baby is getting its power from when most 4 strokes are just beginning to rise out of and idle at 2,800 rpms. When it comes to outboards, what would be the sense in putting a larger prop on a comparable sized (horsepower-wise) 2-stroke outboard if it could not swing that kind of action? As said earlier, it will hole-shot a 4-stroke of the same rated horsepower. Check out the Evinrude Site, where they still build brand new 2 Stroke Outboards called the E TEC series, because I own a brand new E TECH 2 Stroke myself and love it. 2 strokes ... ya gotta love em. Burp ding ding ding ... Love this thread. Tom
When it comes to the end application, one should always consider the differences only applying to that application sense. Like I said before, I own quite a number of 2 stroke engines. From weed whackers to trucks, they have 2 stroke engines in them. My wife's Vanden Plas has an inline 6 (XJ6) 4 stroke gas engine which is the exception to what I own. None of the above can be compared to that of an outboard, be it 4 or 2 stroke. I did not mean to imply that a weed whacker motor had its torque range higher and hence was true to the proclivities defining what a 2 stroke is all about. Never let it be heard from me! Mel, you are only half right. Right in the application sense, but sadly this is more about marine outboards (2 strokers) than Ducati dirt bikes. I could argue the point that my 453 Detroit Diesel is a 2 stroke and its rated output is 495 ft lbs torque at the low end. Also I could argue that my 2 stroke Detroit is warrantied for only 2.8k RPM top end! *yks Ya gotta wonder where that baby is getting its power from when most 4 strokes are just beginning to rise out of and idle at 2,800 rpms. When it comes to outboards, what would be the sense in putting a larger prop on a comparable sized (horsepower-wise) 2-stroke outboard if it could not swing that kind of action? As said earlier, it will hole-shot a 4-stroke of the same rated horsepower. Check out the Evinrude Site, where they still build brand new 2 Stroke Outboards called the E TEC series, because I own a brand new E TECH 2 Stroke myself and love it. 2 strokes ... ya gotta love em. Burp ding ding ding ...
Love this thread. Tom
good prop sources?
I'd like to find a lower pitch prop for my 2 stroke merc 9.8 but hate to go the custom pitch route... $75 to repitch, I figure a new one should be about that.... anyone have prop sources?
I'd like to find a lower pitch prop for my 2 stroke merc 9.8 but hate to go the custom pitch route... $75 to repitch, I figure a new one should be about that.... anyone have prop sources?
Clown
Larger props get a better bite in the water. They don't move a boat as fast due to extra drag, but kickers don't put a sail boat up on plane. Large prop with low pitch will generate more thrust, this is what pushes a boat. High speed is needed to keep a boat on plane, and get better fuel economy out of a planing boat. Thrust is what is needed to pull a boat into the wind, regain momentum after smashing a wave, or stopping a boats forward momentum. Yes changing props does make sence if the prop you have is not working to the motors intended use. Small outboards are used for a large spectrum of applications. They are used as trolling motors, sailboat kickers, dinghy motors, and general power on smaller fishing boats (row boats). Dinghys, row boats, want speed from the small motor, sail boats need thrust, and trolling motors just need to move the boat at a given speed at a usable RPM for long durations. You could troll with a very small 2 cycle running at 3/4 throttle, but not a 4 cycle running at full throttle. A 2 cycle running at near idel would foul it's plugs, so you would either have to get a smaller motor, or a less agressive lower pitched prop to slow the boat down. If you are making hull speed at 3/4 to wide open with a 2 cycle you have the right prop. If you never get any more speed as you open the throttle above 1/2 then your prop is pitched too high. If your prop is pitched too high it will cavitate much easier, and while a prop cavitates there is no thrust or greatly reduced thrust. An engine, 2 or 4 cycle doesn't produce it's full HP untill it reaches or nearly reaches it's top RPM. So lugging a 10 HP motor you may as weel just bought a 5 hp and saved money, weight, and fuel. BUT if you already have the motor, a new prop is much cheaper. Yes a 2 cycle will wind up faster, but that is not torque, and a 4 cycle will run at lower RPMs with out fouling the plugs, so having an over sized 4 cycle is not as much a problem as having an oversized 2 cycle. But 4 cycle engines weigh more to start with, so if 6 hp will do all the work it ever needs to do, 4 or 2 cycle, why get an even heavier 10 HP and lug it. Now if I was pulling 2 25' sail boats behind me everyday, then I guess I'd want that 10 HP, with a large low pitched prop. but I'm not out there to be a tow service.
Larger props get a better bite in the water. They don't move a boat as fast due to extra drag, but kickers don't put a sail boat up on plane. Large prop with low pitch will generate more thrust, this is what pushes a boat. High speed is needed to keep a boat on plane, and get better fuel economy out of a planing boat. Thrust is what is needed to pull a boat into the wind, regain momentum after smashing a wave, or stopping a boats forward momentum. Yes changing props does make sence if the prop you have is not working to the motors intended use. Small outboards are used for a large spectrum of applications. They are used as trolling motors, sailboat kickers, dinghy motors, and general power on smaller fishing boats (row boats). Dinghys, row boats, want speed from the small motor, sail boats need thrust, and trolling motors just need to move the boat at a given speed at a usable RPM for long durations. You could troll with a very small 2 cycle running at 3/4 throttle, but not a 4 cycle running at full throttle. A 2 cycle running at near idel would foul it's plugs, so you would either have to get a smaller motor, or a less agressive lower pitched prop to slow the boat down. If you are making hull speed at 3/4 to wide open with a 2 cycle you have the right prop. If you never get any more speed as you open the throttle above 1/2 then your prop is pitched too high. If your prop is pitched too high it will cavitate much easier, and while a prop cavitates there is no thrust or greatly reduced thrust. An engine, 2 or 4 cycle doesn't produce it's full HP untill it reaches or nearly reaches it's top RPM. So lugging a 10 HP motor you may as weel just bought a 5 hp and saved money, weight, and fuel. BUT if you already have the motor, a new prop is much cheaper. Yes a 2 cycle will wind up faster, but that is not torque, and a 4 cycle will run at lower RPMs with out fouling the plugs, so having an over sized 4 cycle is not as much a problem as having an oversized 2 cycle. But 4 cycle engines weigh more to start with, so if 6 hp will do all the work it ever needs to do, 4 or 2 cycle, why get an even heavier 10 HP and lug it. Now if I was pulling 2 25' sail boats behind me everyday, then I guess I'd want that 10 HP, with a large low pitched prop. but I'm not out there to be a tow service.
Old Engines
If you are still using an old 2 stroke Detroit Diesel I wouldn't think there had been any warrenty left on that for a decade or more. As far as the oil injected 2 cycle engines, they are higher HP then a kicker for a trailer sail boat. I didn't say they don't make 2 cycle engines anymore, just not kickers and dinghy motors. And my last oil injected 2 cycle was a POS. It was a Suzuki and caught fire while I was fishing. Burned the whole boat up off of Anna Maria Island, while I was shark fishing, a very fun night of swimming since I had just put over 30 gallons of chum.
If you are still using an old 2 stroke Detroit Diesel I wouldn't think there had been any warrenty left on that for a decade or more. As far as the oil injected 2 cycle engines, they are higher HP then a kicker for a trailer sail boat. I didn't say they don't make 2 cycle engines anymore, just not kickers and dinghy motors. And my last oil injected 2 cycle was a POS. It was a Suzuki and caught fire while I was fishing. Burned the whole boat up off of Anna Maria Island, while I was shark fishing, a very fun night of swimming since I had just put over 30 gallons of chum.
Thank you - all - for such a quick response - I was unaware of the prop pitch issues and in considering all the advice I am likely to look to order, today a 6hp 4stroke Tohatsu (keep hearing good things about them) which should be a lighter unit (a big issue for me) than my current 9.5 1988 Evinrude. Thanks again - what a great website! Mike
- Status