2 stroke vs. 4 stroke weight.

I have a 1988 boston whaler 135 sport, 13' 4" long, rated for 40 hp(in the days before 4 strokes were common). I would like to replace the 40 hp yamaha 2 stroke as many lakes in my area now prohibit 2-strokes. My present motor weighs about 175lbs. The 40 hp 4 strokes all seem to weigh 200lbs and up. Are boat horsepower ratings based on weight or power? Will the boat handle the extra weight or will i have to go to a smaller (and lighter) engine?

Re: 2 stroke vs. 4 stroke weight.

The classic Sport 13 can handle a 200lb outboard, but I don't recommend it. That is a very light hull and giving it that much stern weight would make it handle badly.

I tried several engines on my Sport 13 and found the improved handling with the lighter engines easily made up for the lack of mach 1 speed. I ended up running a Johnson 25 after rejecting the 200+lb 40 and 50.

Check out the new, "lightweight" Hondas in the 25-30HP range. I think you will find that a top speed of about 30mph isn't that much slower than 35-40.

Good luck.

Re: 2 stroke vs. 4 stroke weight.

Where are you? I'm curious about the 2 stroke rules . . .

Re: 2 stroke vs. 4 stroke weight.

Well, most "banned 2-stroke areas" are just banning the premix motors, so an oil-injected 2-stroke will likely be OK.

Otherwise, as was noted, the weight difference of a 4-stroke may be offset by going down one motor family size. Say for instance getting a 30hp FI Tohatsu/Nissan/Merc. Many 4-strokes have a fairly flat power curve, so they make a lot of torque at the low end, offsetting the lower total hp rating a bit.

Re: 2 stroke vs. 4 stroke weight.

evinrude etec 25-30hp models ranges thinks its like from 150-177 pounds i believe just depends on ur options u know. power tilt electric start log or short shaft. there have great techonology in them. only downside to this motor is the price tag unless u can find a used 30hp but i believe they just came out this year so ya...they claim 3 years no maitenece like tune ups at the dealer but i would change gear oil once a year before freeze and impeller at most 2 years with u know flushing if salt water and other things too all in the manuel. but ya if u like two strokes etec r nice

Re: 2 stroke vs. 4 stroke weight.

pvanv said:

Well, most "banned 2-stroke areas" are just banning the premix motors, so an oil-injected 2-stroke will likely be OK.

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I don't think so. I think it is carbureted 2 strokes that are banned and most DFI 2 strokes are allowed.

Of course, if those politicians understood what they were talking about they would ban the engines that pollute most.

Other places ban all 2 strokes and allow carbureted 4 strokes that pollute more than DFI 2 strokes.

To be able to use an outboard anywhere and far into the future you need an EFI 4 stroke

Re: 2 stroke vs. 4 stroke weight.

I would hope they are banning motors that don't meet "CARB" requirements.
That would include carburated 2 strokes but not the Etec 2 stroke.
The carbed 4 stroke is not particularly clean compared to those motors that meet "CARB" regulations.
You might check out the Etec 30 146#-177# depending on equipment.
Unfortunately the Etec 40 is 240lbs.Its my feeling in the future we may see tha big Etec 40 dropped and a 40 based on the 30 block appear.
Certainly feaseable with 35cu.in. block.

Re: 2 stroke vs. 4 stroke weight.

reted

QC said:

Where are you? I'm curious about the 2 stroke rules . . .

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central california coast. i mainly fish cachuma lake and lately they've
been logging the number of 2 strokes that use the lake. I take this as an ominous sign. they were contemplating banning carbureted 2 stokes a couple years ago but the new oxygenated fuel required in california apparently lessened the emissions enough that they decided not to ban them. most california lakes are drinking water reservoirs. i don't know if other area lakes are also logging 2 strokes, but from past experience with the quagga mussel
situation, whenever one reservoir in this area adopts something, they all follow suit. i'm not sure how many california lakes currently ban carbureted 2 strokes, but diamond vally lake in your area does.

Re: 2 stroke vs. 4 stroke weight.

steelespike said:

I would hope they are banning motors that don't meet "CARB" requirements.
That would include carburated 2 strokes but not the Etec 2 stroke.
The carbed 4 stroke is not particularly clean compared to those motors that meet "CARB" regulations.
You might check out the Etec 30 146#-177# depending on equipment.
Unfortunately the Etec 40 is 240lbs.Its my feeling in the future we may see tha big Etec 40 dropped and a 40 based on the 30 block appear.
Certainly feaseable with 35cu.in. block.

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ya steel i already said all those things....

Re: 2 stroke vs. 4 stroke weight.

well about the weight of the 25-30hp etec

Re: 2 stroke vs. 4 stroke weight.

coolguy147 said:

ya steel i already said all those things....

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You sure did; but I love to talk about the Etec.

Re: 2 stroke vs. 4 stroke weight.

thosk said:

whenever one reservoir in this area adopts something, they all follow suit.

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Yeah, whether it makes sense or not. I am in the engine emission biz and I hate when bureaucrats ban a technology instead of enforcing a standard, this is why I ask where. Kind of keep track of stupidity.

thosk said:

i'm not sure how many california lakes currently ban carbureted 2 strokes, but diamond vally lake in your area does.

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Yes, Diamond Valley for sure. In the case of a Carbed 2 cycle an argument can be made that they can't meet any reasonable standard. I just get really pizzed when I hear of total 2 cycle bans, that's just plain stupid, so I always ask. Also important not to continue the confusion. Thanks.

Re: 2 stroke vs. 4 stroke weight.

QC said:

Yeah, whether it makes sense or not. I am in the engine emission biz and I hate when bureaucrats ban a technology instead of enforcing a standard, this is why I ask where. Kind of keep track of stupidity.


Yes, Diamond Valley for sure. In the case of a Carbed 2 cycle an argument can be made that they can't meet any reasonable standard. I just get really pizzed when I hear of total 2 cycle bans, that's just plain stupid, so I always ask. Also important not to continue the confusion. Thanks.

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As an aside, I believe when they were considering the ban several years ago, they wanted to ban carbed 2 strokes 10 HP & OVER ONLY. DFIs of any hp were ok. I always thought the under 10 hp exemption was probably put in so the lake boat rental concessionaires wouln't have to scrap their entire fleet of 6 and 9.9hp engines!

Re: 2 stroke vs. 4 stroke weight.

The state of California does not ban two cycle engines that were sold as original equipment and remain on the boat they were sold with. However, if you repower your boat it must be done so with an engine that meets at least the minium CARB requirements, (two or four stroke). That's air polutions standards.

As for water quaility/polution standards, that is a whole other set of regulations and can be governed right down to the local level. Lake Tahoe is known to have the most stringent requirements, at least on the California side. The local lake cops now all run E-Tec's and Evinrude has a video that will give you a little insight as to what the Tahoe cops look for.

Local officials are supposed to allow any two or four cycle motor that has a one, two or three star rating but once again that is up to the local authorities and if some county official say's no two cycles then that's the law for that county. It falls into much the same category as horse power and max speed restrictions.

Here's the really bad part, California sets the bar extremely high and generates a ton of revenue doing it to compensate for poor management. Soon after, the rest of the states see the potential for capital gain and follow suit.

All you need to do is follow the money and you'll find out why half of this junk happens. I do aggree that polution of our waterway's is a bad thing and will do what I can do to help but I don't agree that stupid lunatic fringe people should be allowed to hold public office.

Re: 2 stroke vs. 4 stroke weight.

In my recient search for a similar sized moter I learned:

The Tohatsu/Nissan 30 ( with power tilt and trim) weighs in around 182#. Prop it correctly and I doubt you see more than 2-3 mph difference (but likely a big fuel and oil savings). Maybe not even that if you get the power trim option. A new one will run you in the $4000 +/- 200 range right now.
The 40 hp runs about $600 and 23# more.
Last I looked, teh V-Tec's weren't savign any weight in this size range.

BTW: As with any 20 yr old boat, make sure your transom is solid/has no hidden rot before repowering.

Re: 2 stroke vs. 4 stroke weight.

The Tohatsu/Nissan/Merc 25/30 is a 3-cyl EFI 4-stroke, whereas the Tohatsu 40 is a TLDI. Since the 30 is cheaper, lighter, and has tilt assist out of the box, I would consider that the front runner, unless you want the extra hp.

Re: 2 stroke vs. 4 stroke weight.

I powered my 14' tinny with a 18hp Nissan 4 stroke (Tohatsu). I get 24mph out of it at 6250 rpm with their #10 prop at just above sea level (22mph at 5200 ft.). It weighs in at 114lbs. They've bumped this same motor up to 20hp now and it's a perfect fit. My 14 is heavy but I still hit max RPM without any problem.

My brother has the same exact boat and has a 25hp Johnson 2 stroke. On a long run he will beat me but it takes him a while so the difference in speed is not all that much. The really big difference is the 3 star rating and at wide open throttle it burns 1/2 gallon an hour.

As an added bonus, this motor was purchased new in 2002 and has never been in the shop for anything. I change all the lubes regularly and the impeller and plugs once a year. I use it almost every weekend from March through November so it gets a workout but performs the same now as it did new.

This might be a good option for you since it definitely proves that less can be more.

Re: 2 stroke vs. 4 stroke weight.

I think your fuel economy numbers are off. My 9.8 Nissan 4-stroke is rated at 1.0 GPH at WOT. According to Tohatsu's website, http://www.tohatsu.com/tech_info/fuel_consumpt.html your 18 should burn 1.5 GPH at WOT. Only the 5 hp unit is that easy (half gallon/hour) on fuel.

Don't misunderstand, I love the Tohatsu/Nissan/Merc 9.9/15/18/20 family for what they were intended. I maintain a fleet of these motors, and they are incredibly tolerant of abuse.

Still, I think he wants more than 18/20hp for his use.

Re: 2 stroke vs. 4 stroke weight.

pvanv said:

I think your fuel economy numbers are off. My 9.8 Nissan 4-stroke is rated at 1.0 GPH at WOT. According to Tohatsu's website, http://www.tohatsu.com/tech_info/fuel_consumpt.html your 18 should burn 1.5 GPH at WOT. Only the 5 hp unit is that easy (half gallon/hour) on fuel.

Don't misunderstand, I love the Tohatsu/Nissan/Merc 9.9/15/18/20 family for what they were intended. I maintain a fleet of these motors, and they are incredibly tolerant of abuse.

Still, I think he wants more than 18/20hp for his use.

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Humm, I'll recheck the calibration on my fuel flow meter and sending unit. It's been right on the money as far as fuel used and what I put in at the pump. I didn't quote the Tohatsu site numbers. The numbers I got were taken at WOT. I wonder if its because its an older model or I wonder if it's averaging. It shouldn't be working that way, I'll have to call Lowrance.

Thanks for the insight.

Re: 2 stroke vs. 4 stroke weight.

Interesting Link. Generally speaking it appears that you can plan on 1gal/hr for every 10 hp @ WOT. A little less for 4 strokes, a little more for 2 strokes. pretty close though. I wonder how the other brands match up?