2 Stroke > 4 Stroke or 4 Stroke > 2 Stroke

Holden · March 06, 2007, 05:43:23 PM

We are close to buying a boat and are stuck on what kind of motor to get. 25 hp 4 Stroke or 50 hp 2 Stroke. What do you guys suggest. What is different between 4 and 2 stroke motors. Thanks,

KBK

Bassinkorea · March 06, 2007, 05:44:50 PM

Good question. I'm hoping to learn something from this also.

Beagle · March 06, 2007, 10:07:55 PM

The 4 stroke will be alot more quite but your not fshing while your running so it really don't matter. Go with the 2 stroke 50. It will be faster. Don't know what boat your looking at but I just bought a 2007 xpress 17ftr with a 90 Yamaha. It was only about $13,500

Bassinkorea · March 06, 2007, 10:19:47 PM

Nice looking boat, I'm jealous.

AB · March 06, 2007, 10:24:27 PM

Many differences. The 4 stroke is very similar to your car engine. The induction system utilizes camshafts that operate intake and exhaust valves that open and close to allow fuel/air into and out of the cylinder. The firing event happens on every other revolution of the engine per cylinder. On a 2 stroke, the air passes through the intake, then through intake ports ground into the cylinder wall as the piston travels down. When it travels back up it passes (and therefore closes) the intake port, then fires the mix, then the mix pushes the piston down and goes out the exhaust port. At the same time new mix is being brought in through the intake port. A firing event happens on every revolution of the engine per cylinder.

On the small Stratos 176XT we have found that the 60 Etec will outrun the 75 Yamaha 4 stroke. It also uses less fuel, less oil (since the Yamaha has to have the oil changed every year) and is just as quiet. If you buy NOW NOW NOW you can get 7 years of warranty coverage on the Etec. That is a spring show season promo that is ending VERY soon...

Beagle · March 06, 2007, 11:10:38 PM

I'm sure the 60 Etec is a fine motor but I wouldn't trade it for my 90 Yamaha 2 banger. It pushes my boat faster than I want to go. It will approach 60 with just me in it.

coldfront · March 09, 2007, 02:47:52 PM

It's quite possible that a 90 E-tec may out-perform that Yamaha. But you are correct: 60 is awful fast...but it's kind of nice to know you can throttle back and still run in the 40's...I've never been a fan of running engines wide open for very long...

Prefer 3/4 throttle or lower whenever possible...as for me, someday I hope to get as nice a boat as that, Beagle. Congratulations...and yes, I frankly am just a bit jealous....

scatch1 · March 11, 2007, 09:20:52 AM

I would go with the 50hp. motor will not have to work as hard.

OutdoorFrontiers · March 11, 2007, 01:42:44 PM

With a 4 stroke motor, you're typically looking at a heavier engine as well as more complex and more moving parts. The horsepower to weight ratio just isn't there on a 4 stroke although their fuel economy is better than the old technology 2 strokes.

Two stroke outboards built today are just as fuel efficient and environmentally friendly as far as emissions go as the four strokes.

So, unless you plan to do a lot of motor trolling, pulling crankbaits and the like, you'd be better off with the two stroke outboard.

Steve

J10B · March 18, 2007, 10:25:12 AM

4 stroke... heavier, more expen$ive to fix, terrible holeshot, terrible top end. Quiet is a personal measure. If you are concerned about the noise level of a 50hp motor... get out of outboards now. Or wear hearing protection. You arent gonna be going fast enough to not hear your buddy talk and if I can talk to my pard going 50 with a 225 racing motor you can DANG well plan on talk with a 50 hp 2 stroke wound up.

A 50hp at best fuel economy rpm is going to be lighter, faster, and more efficent than a 25 hp fourstroke. To get the some perfomance you are gonna need a 75 to get close and more like a 90 4stroke to match. Why because you arent gonna have you foot to the floor in a 2 stroke and be in the best endurance part of the 2 stroke.

4 stroke was and is a gimmic, if you have a problem occansionally mixing your oil, or filling the oil res, you need to rethink fishing. In that case use the boat payment money for a guide and you wont have to lift a finger.

That whole quieter BS is jsut that. That whole economy thing... BS it was comparing to the OLD 2 strokes.
If you cant tell you couldnt give me a 4 stroke. Unless it had a chain and an auto winch so I could use it as an anchor for a party barge.

Ron Fogelson · March 18, 2007, 12:40:45 PM

Dude did you lose your prescription or just run out of happy pills

Quote from: J10B on March 18, 2007, 10:25:12 AM
4 stroke... heavier, more expen$ive to fix, terrible holeshot, terrible top end. Quiet is a personal measure. If you are concerned about the noise level of a 50hp motor... get out of outboards now. Or wear hearing protection. You arent gonna be going fast enough to not hear your buddy talk and if I can talk to my pard going 50 with a 225 racing motor you can DANG well plan on talk with a 50 hp 2 stroke wound up.

A 50hp at best fuel economy rpm is going to be lighter, faster, and more efficent than a 25 hp fourstroke. To get the some perfomance you are gonna need a 75 to get close and more like a 90 4stroke to match. Why because you arent gonna have you foot to the floor in a 2 stroke and be in the best endurance part of the 2 stroke.

4 stroke was and is a gimmic, if you have a problem occansionally mixing your oil, or filling the oil res, you need to rethink fishing. In that case use the boat payment money for a guide and you wont have to lift a finger.

That whole quieter BS is jsut that. That whole economy thing... BS it was comparing to the OLD 2 strokes.
If you cant tell you couldnt give me a 4 stroke. Unless it had a chain and an auto winch so I could use it as an anchor for a party barge.

AB · March 18, 2007, 01:16:07 PM

Every motor has its application. If I had a center console that spent weekends offshore trolling for dolphin, you'd better bet it would have a Yamaha 4 stroke or Verado on the back of it. Can't beat a 4 stroke for slow trolling all day long. Same thing for a kicker motor on a Walleye boat. 2 strokes just don't like hours on end of slow trolling.

But, in an application where the motor is only going to be idling long enough to get away from the ramp

, then it's 2 stroke all the way.

J10B · March 18, 2007, 09:03:55 PM

Quote from: AB on March 18, 2007, 01:16:07 PM
Every motor has its application. If I had a center console that spent weekends offshore trolling for dolphin, you'd better bet it would have a Yamaha 4 stroke or Verado on the back of it. Can't beat a 4 stroke for slow trolling all day long. Same thing for a kicker motor on a Walleye boat. 2 strokes just don't like hours on end of slow trolling.

But, in an application where the motor is only going to be idling long enough to get away from the ramp , then it's 2 stroke all the way.

ok if you are an offshore guide.. OK. Other than that. NOPE

topcat · March 19, 2007, 10:46:39 AM

Great info here I learned a lots in this thread.......

Topcat

2007Nitro · April 12, 2007, 05:20:53 PM

You guys need to check the spec on the 4 strokes again!! I have a mercury 60hp 4stroke pushing my nitro 640 and i love it!!! my buddy has exact same boat as me, but his is a year older(2006) and he has mercury 75hp 2 stroke and iam pulling away from him every time!! Granted i was slower out of the hole But once i put a hyrdofoil on I plain up much faster then him now!! Keep in mind Iam talking about a 60hp iam not sure how 2 and 4 stroke compare in bigger motors:] check this out the site it looks to me that 4 strokes have more WOT rpm then a 2 stroke and only weight 30lbs more which keep in mid isnt much when u think a loaded live well is weights 210lbs( water X time weight of water is 8.4lds a gallon and average live well is 25 gallons which equals 210lbs) Well iam sure you can research the rest yourself:]

http://www.mercurymarine.com.au/mpi/mmproddb.nsf/Products+Main+Page?openform&Restrict=MERCURY%20OUTBOARDS

60 EFI 4 stroke:
Detailed Specifications
Propshaft Rated Horsepower:
60 HP (44.7kw)
Max RPM at Full Throttle:
5500-6000
Cylinders:
4
Displacement:
60.8 cu in. (995cc)
Bore & Stroke:
2.56 in. x 2.95 in. (65mm x 75mm)
Cooling System:
Water cooled with thermostat
Ignition:
ECM 555 Digital Inductive
Starting:
Electric
Gear Ratio:
1.83:1
Gear Shift:
F-N-R
Steering:
Tiller or Remote
Alternator System:
20 amp (252 watt)
Trim Positions:
Power Trim Standard
Fuel Tank:
Optional
Weight:
248 lbs (112 kg)
Propeller Drive:
Splined Rubber Hub
Recommended Boat Transom Height:
Long 20" (508 mm) 25" models available
Propeller Option:
See Dealer
Prop Selection (Pitch):
8" - 19"
Induction System:
2-Valve single overhead cam design
Oil Injection:
N/A
Counter Rotation:
N/A
SmartCraft Capabilities:
Yes

60hp 2 stroke:
Detailed Specifications
Propshaft Rated Horsepower:
60 HP (44.8kw)
Max RPM at Full Throttle:
5000 - 5500
Cylinders:
3
Displacement:
59 cu in. (967cc)
Bore & Stroke:
2.99 in. x 2.80 in. (76mm x 71mm)
Cooling System:
Water cooled with thermostat and pressure controlled
Ignition:
Modular CDI
Starting:
Electric
Gear Ratio:
1.64.1
Gear Shift:
F-N-R
Steering:
Remote or Tiller
Alternator System:
16amp (201 watt) with voltage regulator electric start
10amp (126 watt) manual start
Trim Positions:
Gas assist & Power trim models available
Fuel Tank:
Optional
Weight:
219 lbs (99.5kg)
Propeller Drive:
Splined rubber hub
Recommended Boat Transom Height:
Long 20" (508mm) & 22.5" model available
Propeller Option:
See Dealer
Prop Selection (Pitch):
8" - 19"
Induction System:
Loop-charged (3 carb)
Oil Injection:
Standard
Counter Rotation:
N/A
SmartCraft Capabilities:
N/A

OutdoorFrontiers · April 12, 2007, 05:45:46 PM

2007Nitro,

You're not comparing apples to apples. If you're running away from him with 15 less horsepower, but getting on plane slower (without the hydrofoil), you're propped taller than he is and as such, will have a higher top end, or he's carrying a lot more gear and weight. Propping is an amazing thing. It would be interesting to compare both boats empty, propped for ideal performance, without the hydrofoil.

Four stroke technology has come a long way, but the horsepower to weight ratio is still in favor of the two stroke motors and they will rev up quicker, allowing the boat to get on plane and up to speed quicker, without planing aids. Four strokes once did have an advantage in being more environmentally friendly (less emissions) with better fuel economy over two stroke engines. But that is no longer the case, high pressure, direct injection technology has also improved tremendously in the past couple of years as well. I have several friends with new four stroke engines and I'm just not impressed with the performance of the motors. A friend of mine has an 18 foot Crestliner with a 130 Honda and even with far less gear than I would carry, it takes forever for the boat to plane out.

The main advantage I see with four stroke outboards is for trolling long periods of time. Two stroke outboards just won't idle at low rpm's for long periods of time without "loading up" where a four stroke will. I'd rather have the simplicity of a two stroke, I'm a caster, not a troller.

Steve

2007Nitro · April 12, 2007, 07:28:43 PM

OutdoorFrontiers

I do agree with ya in someways about 2 strokes it all comes down to what you want out of a motor!!!
If i had a bigger bassboat that needed over 150 to power it i would go with the 2 stroke too but in my cause with a small bassboat i like the 4 stroke better. Iam also a beat up the bank kinda guy, main reason i got the 4 stroke was the 7 year extendable warrenty it comes with!!! This is my first 4 stroke and iam happy with the performance I can only really compare it to motors of its same size and it has prove it can hang with motors rated higher.