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Thread: My 2-stroke vs. 4-stroke positon w/ data

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    Default My 2-stroke vs. 4-stroke positon w/ data

    Okay, last post to hopefully let you know where I come from and actually data used to formulate that. All data and quoted material is from the Kenai Watershed Forum Non-point Source Pollution Monitoring – Hydrocarbon Fact Sheet.

    First quote: “Some agency partners have pointed to source of pollution in the inefficiency of 2-stroke engines. During operation, both the intake and exhaust ports are open at the same time, this allows fuel to pass directly through the engine. As much as 25% of the consumed fuel passes directly to the air or water, releasing toxic and carcinogenic materials, such as hydrocarbons to the environment”

    I think we all pretty much knew that about the old 2-strokes, although I was somewhat surprised that it was as much as 25% raw fuel passed through.

    Second quote: “Following this potential source, and at the request of the National Marine Fisheries Service, KWF conducted reconnaissance work in an attempt to determine the ratio of 2-strokes engines to 4-stroke engines in use on the river during the month of July and Early August. Based on 775 observations, we found 34%of the motors were 2-stroke, and 66% 4-stroke. However, we also noted that there are distinct and dramatic differences within specific user group populations. Our data indicated that more than 90% of guided motor boats were using 4-stroke engines compared to less than 50% of private boaters using 4-stroke.

    Taking 34% from a total of 500 boats on the river during a peak use day (170 two-strokes), and estimate of 10 gallons of daily fuel consumption per boat, it is reasonable to assume that 400 to 500 gallons/day of raw fuel could be entering the river from this motor type.”


    Yes, guides are running 4-strokes, we all know that, mainly because they are more fuel efficient and very quiet on the water. The non-guide 2-strokes are a significant source of raw fuel. 34% of the motors on the river being 2-strokes is significant. The information did not give an amount of hydrocarbon put in by four stroke engines. I know they presented some information to one of the groups on the Peninsula and stated that carbureted 4-strokes put in about a cup of fuel per 10 gallons while fuel injected 4-strokes were at least half that. 2-strokes were stated to put in 2 to 3 gallons of fuel per 10 gallons.
    Also, Kenai Watershed Forum has stated that on peak use days there was an estimated 600 gal/day of raw fuel being put into the Kenai. They also state that 2-strokes put in 400-500 gallons of that. It is illogical not to start there when trying to reduce Hydrocarbons.

    Marcus you stated on a post something about taking the mom and pop fishermen that use the river 2 or 3 times a year with a 2-stroke. Granted a guide that fishes day in and day out will put in more HC in motor to motor pure hourly over a season comparison but if you add up the 2 or 3 time a year user with a 2-stroke it becomes a significant amount of HC. 170 boats with 2-strokes out of a total of 500 boats is a lot of HC by the 170 two strokes. One could also argue that per river user (clients) guides attribute the least amount of HC per river user.

    This is the data from which I have formed my 2-stroke vs. 4-stroke position. Could I live with no 2-strokes in July and allowed the rest of the year, “Yes”. Or maybe not….

    Third quote: However the highest values do not exist in July as our grab samples may suggest, but rather in May, when very low boat traffic is present.

    May is a pretty high run-off month with low flows, accounting for what appears to be a lot of HC. The Kenai Watershed Forum did not elaborate on this statement but I find it very interesting. I wouldn’t necessarily attribute the high level to 4-strokes or 2-strokes.

  2. #2

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    Good post Yukon. It's clear that removing the old technology from the river is the right course of action for the river. The State is attempting to do SOMETHING, rather than nothing.

    And before we hear about the dreaded horse power increase and "How could we increase the HC in the same breath...please save it. The two issues were tied together in one regulation, one for hydrocarbons, and one for erosion.

    It's obvious to me as a non-guide why 50 was chosen, and why old 2-strokes need to be replaced.

    The fact that the State is taking action is huge. If nothing was done by the State, the Feds surely would. I know some on this board would rather see federal control, but I'm not one of them.

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    Default "Granted a guide that fishes day in and day out will put in more HC. . ."

    Quote Originally Posted by Sockeye Charlie View Post
    . . .before we hear about the dreaded horse power increase and "How could we increase the HC in the same breath...please save it. The two issues were tied together in one regulation, one for hydrocarbons, and one for erosion.
    Regardless of how that cheese is sliced, it smells the same. One user group is being made to pay for a problem created by and contributed to by many user groups while, at the same time, another user group is being allowed exacerbate the problem. . .

    I'd rather see an across-the-board cut in motorized use of the river.

    Time will tell. . .


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    Moderators: Have you ever considered a "Kenai River Debate" forum?

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    Moderators:

    Point of order - this thread is not about fishing; please move to appropriate location (power boating, general discussion, kenai river debate, you decide).

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    Default Some problems Yukon...

    There are some basic problems with that information Yukon.

    I understand fuel scavenging, and certainly recognize that 4-stroke outboards produce less hydrocarbons than the old 2-strokes. And I am not against removing 2-strokes during July when hydrocarbon levels are exceeded.

    But....

    The 25% figure isn't for 35 hp outboards. And it's not for the Kenai River. That figure is merely referenced from studies like Lake Tahoe's, as stated in the KWF Fact Sheet itself. Those and similar studies primarily include personal water craft (PWC's or Jet-Ski's) and outboards of all sizes, from 2 hp to 300 hp.

    As KWF's Fact Sheet acknowledges, there is no data that shows any 2-stroke 35 hp outboard operated on the River spews 25% of its fuel into the water. That is possibly grossly over-stated.

    To make matters worse, this assumed/guestimated 25% figure is used to assume/guestimate how much raw fuel is entering the River. Again, possibly over-stating that. To top it off, they "estimate" that each outboard uses 10 gallons of fuel/day, which in my experience is over-stated.

    The problem with their 2-stroke/4-stroke user ratio's is that, although they identify the two user groups (guided and non-guided), they fail to recognize how long a typical 2-stroke user (non-guide) might be on the River compared to a typical 4-stroke user (commercial guide). Additionally, they arbitrarily use 500 boats as the sample quantity.

    Even the KWF seems to agree that it is all based on hypotheses:

    "With the amount of data we have we can only speculate and it would be prudent to have these hypotheses independently tested."

    "The data presented herein has not been peer reviewed and is limited in scope."

    In my opinion, it is a grave mistake to only look at one user in this issue. We are certainly in no positition to increase hydrocarbon levels for the other user, just so he can push a bigger boat faster, in the name of supposidly reducing bank erosion.

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    Not sure where you got your info but again, straight from the Fact-sheet:

    "Following this potential source, and at the request of the NationalMarine Fisheries Service, KWF conducted reconnaissance work in an attempt to determine the ratio of 2-stroke engines to 4-stroke engines in use on the river during the month of July and Early August. Based on 775 observations, we found 34% of the motors were 2-stroke and 66% 4-stroke."

    That is Kenai River Data, not Lake Tahoe.

    What are we supposed to do with your quote, throw out the entire document and wait for it to be peer reviewed or further studied. Basically sit and wait and do nothing?

    You are making many personal assumptions, which don't hold any water, not even a drop. Are you personal assumptions peer reviewed or has a study been done to verify them????? Because that is what you are asking of others, lets keep it fair. Unless your observations are better than the KWF study and scientific observations.

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    The "rule of thumb" for 2-strokes is that they put 10-25% of the fuel used back into the water - 25% is an overstatement (just as 10% is an understatement). (P. Warrington, Impacts of Outboard Motors on the Aquatic Environment, 1999) .And the data I reviewed excluded PWC.

    I wouldn't get too wrapped around the word useage of "hypotheses", as in the scientific world everything is a hypothesis until proven by the data.

    As far as the referenced data goes, right now it's the best available - which is better than no data. I've seen the data re: emissions and the need for elmiiating the 2-strokes, is there published data from a study regarding the reduction of erosion by increasing the hp?

    SH

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    Yes, there is some data from Phase II of the boat wake study. I am working on that one. I don't have a ton of time right now but I will get it done.

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    Quote Originally Posted by yukon View Post
    "Following this potential source, and at the request of the NationalMarine Fisheries Service, KWF conducted reconnaissance work in an attempt to determine the ratio of 2-stroke engines to 4-stroke engines in use on the river during the month of July and Early August. Based on 775 observations, we found 34% of the motors were 2-stroke and 66% 4-stroke."
    Using this data, if each 4-stroke were to emit 1 unit of HC and each 2-stroke 10 units (given the ratio of 10:1 (2stroke to 4stroke) previously cited), the 511 boat 4-stroke fleet would emit 511 units of pollutants, while the 264 2-strokes would emit 2640 units . . .

    In other words, 33% of the boats emit 84% of the total contaminants released during the observation period. . .

    SH

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    Quote Originally Posted by yukon View Post
    Yes, there is some data from Phase II of the boat wake study. I am working on that one. I don't have a ton of time right now but I will get it done.
    Thanks,

    SH

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    Quote Originally Posted by yukon
    That is Kenai River Data, not Lake Tahoe.
    If you read the KWF's Fact Sheet that was referenced, you'd see that the 25% figure comes from Lake Tahoe's model, and other similar models. If you read that Lake Tahoe report you would see that it pertains to PWC and all outboard sizes, in a lake environment. It does not pertain to 35 hp 2-strokes, particularly those operated in the Kenai River.

    If you read the Fact Sheet you will also see where KWF admits their assumptions with regard to their 10 gal/day, 500 boats, and their guess at how much raw fuel is entering the River.

    And that is exactly why they call it a "hypotheses" that contains unreviewed data, and why they suggest further independent testing.

    Where's this data that shows a 35 hp 2-stroke spewing 25% of its fuel into the River? Where's this data showing that a 2-stroke user puts 10 gallons of gas through his outboard per day? Where's this 500 boats on a peak day coming from? Where's this figure of 400-500 gallons of raw fuel coming from?....

    Hypothesis. You can turn that into anything you want Yukon. It will hold no traction.

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    From Impacts of Outboard Motors on Aquatic Environments, P. Warrington, 1999:
    The typical current designs of outboard 2-cycle engines have been estimated to contribute between 1% and 40% of their fuel to the water over their lifetimes; depending upon what study one consults. 10%-25% is a probably a good estimate under normal use of modern engines with crankcase recycling.
    SH

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    I still don't see where that link answered Grampyfishes question.

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    Quote Originally Posted by AKBighorn View Post
    I still don't see where that link answered Grampyfishes question.
    It addresses only the question regarding the amount of fuel released into the water column by 2 stroke engines . . . the rest of the "data" is left to stand (or fall) on its' own.

    Cheers,

    SH

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    Your generic loop scavenged carburated 2 stroke is going to be pumping roughly the percentag of fuel out the exhaust whether it is 2 horse or 200 horse, 2cc or 2 liter. It is what it is, and getting hung up on not having specific data on 35 horse motors on the Kenai is moot. So maybe it's 18, or 20 or 22 percent, your still in the same ballpark. You'll find some motors in ill states of tune that'll be pumping out more, some finally tuned ones a bit less.

    The old two strokes are gross poluters, and is there a justification for folks to run them and put out 10 times the pollution of a modern engine? I can see that as the perfect justification of the I got mine screw you approach. I've been on the river forever, and if I can run the rivers and keep 9 more boats off the river due to the pollution I spew, the better the fishing experience for me.

    I just can't see folks that claim to love the fishery being so blind about pumping pollution into the watershed. I hear all the comments about how the guides are the biggest problem and are greedy and selfish, but to me, those run the old fuel spewing o/b's are truly the most selfish folks on the river.

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    Quote Originally Posted by Grampyfishes View Post
    If you read the KWF's Fact Sheet that was referenced, you'd see that the 25% figure comes from Lake Tahoe's model, and other similar models. If you read that Lake Tahoe report you would see that it pertains to PWC and all outboard sizes, in a lake environment. It does not pertain to 35 hp 2-strokes, particularly those operated in the Kenai River.

    If you read the Fact Sheet you will also see where KWF admits their assumptions with regard to their 10 gal/day, 500 boats, and their guess at how much raw fuel is entering the River.

    And that is exactly why they call it a "hypotheses" that contains unreviewed data, and why they suggest further independent testing.

    Where's this data that shows a 35 hp 2-stroke spewing 25% of its fuel into the River? Where's this data showing that a 2-stroke user puts 10 gallons of gas through his outboard per day? Where's this 500 boats on a peak day coming from? Where's this figure of 400-500 gallons of raw fuel coming from?....

    Hypothesis. You can turn that into anything you want Yukon. It will hold no traction.
    Grandpafishes, go ahead and show your refusal to look at the data, it makes you look bad. All my information quoted in red is from the Kenai Watershed Forum Hydrcarbon Fact Sheet. If you have a problem with the data take it up with them.

    Do you have better data the The Kenai Watershed Forum on 2-strokes?? Any????

    Do you have any, and I mean any, data to support any of your postitions????

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    Quote Originally Posted by Sierra Hotel View Post
    The "rule of thumb" for 2-strokes is that they put 10-25% of the fuel used back into the water - 25% is an overstatement (just as 10% is an understatement). (P. Warrington, Impacts of Outboard Motors on the Aquatic Environment, 1999) .And the data I reviewed excluded PWC....
    Good reference. Thanks.

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    I am not disputing whether or not 2 strokes are polluters. Everyone knows they are. The point is the data provided in your link is not clear. It states that a 2 stroke motor may dump between 1% & 40% of the fuel used into the water. That is in my mind a substanial difference and a broad statement. Is that because of the motor manufacturer design or is it the HP of the motor or what? I would bet that in none of the places these studies were done did they study a 35HP motor as there isn't technically a 35HP motor made per some of your own previous statements. It sure wouldn't hurt to clear the mud here rather than skirt the issue. If these motors are indeed dumping 40% well then the answer is cut and dry in comparison to 4 strokes. IF in fact they dump much less into the water in which nobody can seem to answer then they may not be near as bad as you all make them out to be and therefore there might be a better alternative to address the issue at hand.

    Yes that might mean that all the people operating 4 strokes might not be doing as much good as you all think. I am of the opinion that better statistics need to be presented to correctly identify the problem rather than jump to conclusions with what I would consider inadequate information. Marcus just might be on to something here with his idea of limiting the use of the resource with motorized boats, LIKE IT OR NOT!

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    Quote Originally Posted by yukon
    Grandpafishes, go ahead and show your refusal to look at the data
    Exactly what data do think I'm refusing to look at?

    I see no data that showing a 35 hp 2-stroke operated on the Kenai River spews 25% raw fuel back into the water.

    I see no data that shows each 2-stroke user consumes 10 gallons of fuel per day.

    I see no data that shows 2-strokes putting 400-500 gallons of raw fuel into the River per day.

    I see no data supporting the peak-day 500 boat figure used.

    I see lots of data supporting the fact 2-strokes produce more hydrocarbons than 4-strokes, and I have not contended that. In fact I have repeatedly supported removing 2-strokes during July when the River is impaired.

    What I'm afraid I'm also seeing are several consecutive factors that are overstated. When they add up, or compound, the result is a gross overstatement. And that gross overstatement is directed toward one user group, while another user group is allowed to increase hydrocarbons (to 50 hp).


    Quote Originally Posted by yukon
    All my information quoted in red is from the Kenai Watershed Forum Hydrcarbon Fact Sheet.
    And everything I said is from the same KWF Fact Sheet you referenced:

    Clearly the KWF is discussing 2-stroke engines in general, and not specifically discussing 35 hp 2-strokes operated on the Kenai....

    "A more comprehensive discussion of two-stroke engines can be found on the internet at http://www.trpa.org/Boating/boattahoe.html (Environmental Assessment for the prohibition of certain two-stroke powered watercraft 1999). The pollution generated by this motor type has led to restrictions in other parts of the country, as in the referenced Lake Tahoe example, and is a potential source of pollution in the Kenai River. However, there is no known prior documentation on the relative use of 2-stroke engines in Alaskan waters."

    Furthermore, if you read the KWF's referenced Lake Tahoe report (available on-line), you will clearly see that it deals with PWC's and all sized outboards, in a lake environment.


    The KWF clearly admits to estimating fuel consumption...

    "...an estimate of 10 gallons of daily fuel consumption per boat"


    The KWF clearly admits to estimating how much raw fuel is entering the River from 2-strokes. In fact they base that assumption on prior assumptions that a 35 hp outboard spews 25% raw fuel back into the River and has a 10 gallons/day usage...

    "...it is reasonable to assume that 400 to 500 gallon/day of raw fuel could be entering the river from this motor type."


    The KWF makes no mention of how they determined 500 boats to be the defined quantity on a peak day...

    "Taking 34% from a total of 500 boats on the river during a peak use day"


    Absent of data, the KWF makes these comments...

    "With the amount of data we have, we can only speculate and it would be prudent to have these hypotheses independently tested."

    "All potential sources have not been identified, nor addressed equally."

    "The data presented herein has not been peer reviewed, and is limited in scope."

    "Additional and more frequent sampling is required to verify and better characterize the issue of hydrocarbon pollution in the Kenai River Watershed".

    I suppose the KWF Fact Sheet could be used as a "rule of thumb". I see where the Fact Sheet points to 2-strokes as a "potential source", where it describes that 2-strokes pollute more than 4-strokes, and where they propose a hypotheses. But both Yukon and Mark are wanting scientific data. Sorry, this ain't it.

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