Is there any real difference in 2 stroke fuel economy/emissions throughout the years?

[240sx4u]

Okay, not looking to make this political or start brand wars here.

This is the situation, I will be buying a 40hp outboard and REALLY want an old merc mark series from the 50s like I had on this boat years ago. Lots of memories, and it has sentimental value to me.

I will need a 40hp outboard. Now my question is this. Are most well maintained 2 stroke motors going to put out the same quantity of emissions and give me the same fuel economy? I don't want to leave the water looking like the exxon valdese tipped over every time I stop. I definitely don't have the money for a four stroke, and don't want the weight (boat sits low in the rear anyway).

I know this is a general question, but am not sure what the answer is even after doing searches for an hour. I am a gearhead, so maintaining and keeping everything running well is not a problem.

Thanks! - Evan

Also, wanted to thank everyone for your help. This forum is an amazing wealth of knowledge!

 

[crb478]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

The newer 2 strokes will be more efficient than the older two strokes. The induction systems are more efficient and the tolerances are tighter. The older motors will still work just fine and you can use synthetic oils which are more biodegradable to help with any excess oil issues. Being a 2 stroke it needs the oil for lubrication so even the newest motors will have some excess oil.

 

[Chinewalker]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

Hi Evan,
Typically, older motors are going to pollute more than newer ones. Water pollution simply wasn't an issue that was being dealt with in the 1950s. By the 1970s there were some controls in place and most motors had done away with the fuel dumps (.ie Johnrude Big Twins with the bleeder valve that dumped right into the motor leg) and were recirculating that unburned fuel into the motor. They had also gone from 12:1/16:1/24:1 to a more or less industry-wide 50:1 by the 1970s, so there was less oil being introduced into the environment.

Also, keep in mind that a well-tuned motor will run more efficiently with fewer waste products than one that is tired and out of tune. You can experiment with different oils, synthetics, etc. to reduce your oil slick.

Hope that helps...
- Scott

 

[240sx4u]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

Alright, the fuel dump scenario is the one I think I have seen played out before. Motor stops, and film occurs.

When the time comes, I will put some careful thought into it as far as age of motor. Sounds like it makes sense to get something mid 70s or newer though.

Thanks guys.

Evan

 

[steelespike]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

As long as you are considering newer technology consider this.When I traded up from my 67 40 evinrude to a new 77 50 Merc there was a noticeable improvement in mileage and when I went to new 88 50 Evinrude there was a further improvement.There also appeared to be less slick on the water with each motor improvement.I don't think there is much mileage improvement in motors newer than 88 but they are surely cleaner.

 

[240sx4u]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

As long as you are considering newer technology consider this.When I traded up from my 67 40 evinrude to a new 77 50 Merc there was a noticeable improvement in mileage and when I went to new 88 50 Evinrude there was a further improvement.There also appeared to be less slick on the water with each motor improvement.I don't think there is much mileage improvement in motors newer than 88 but they are surely cleaner.

This is the kind of information I was hoping for. I am still not totally sold on keeping my specific boat so my options are somewhat open still.

Thanks so much.

Evan

 

[Silvertip]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

And the new Evinrude E-tec is head and shoulders above all others for emissions. Economy is better, service intervals much longer, warranty is good, and the engines simply perform better. Obviously more money but what the heck, keep the economy going.

 

[240sx4u]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

And the new Evinrude E-tec is head and shoulders above all others for emissions. Economy is better, service intervals much longer, warranty is good, and the engines simply perform better. Obviously more money but what the heck, keep the economy going.

I would love to take the plunge, but want to get my feet wet first to find out what suits me. I could end up with a basically totally new boat. Who knows! I definitely like the E-tec if some cash falls in my lap though.

Evan

 

[dingbat]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

I don't think there is much mileage improvement in motors newer than 88 but they are surely cleaner.

I'm not sure it holds true in the smaller displacement outboards but in the higher HP motors the fuel efficiency has increased substantially since the late 90?s let alone the 80's

My 1997 200 HP uses noticeably less fuel than my 1986 175HP did and the new DFI motors use 30-40% less fuel than my carbed 1997.

 

[JB]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

I have found without exception that loop scavenged engines are more fuel efficient than cross scavenged of the same HP.

 

[240sx4u]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

Just did some reading on a looper, interesting design. Makes a lot of sense.

Thanks - Evan

 

[Kev144]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

Ah the one thing that interests me now about BRP (evinrude) is their newer HO series. Maybe I will have to give a go even though black runs in my veins! The higher HO's are what i've been waiting for plus a few years under the belt with E-tec.

 

[240sx4u]

Re: Is there any real difference in 2 stroke fuel economy/emissions throughout the ye

I keep waivering back and forth when it comes to outboards. I certainly can't justify slapping a 5k outboard on a 400 dollar boat! haha.

However, if that 400 dollar boat turns out to be perfect, and leaves me desiring nothing I would likely take the plunge.

Evan