Ethanol causing lower RPM @ WOT?

[Giz_]

Hi:

Last year when I winterized my '72 50 hp Evinrude, it was running perfectly.

This week I took it out for the first time this year. Filled the tanks with 10% ethanol gas that we now have.

Boat took significantly longer to reach plane, ran about 400 fewer RPMs less at WOT than last year, and I'm sure top speed was affected a couple mph, too.

I'm suspecting the ethanol. Gonna find a retailer who sells the unblended fuel (REAL gas) and try a tank of that to see if it returns my engine to it's former performance.

Pulled plugs and they look dark and a bit wet. Gonna replace them.

I'd appreciate your thoughts and experiences.

For the record....what are the chances that 1 6 gal tank of ethanol has fouled my carbs with dissolved rubber gunk?


Thanks!

 

[countvlad]

Re: Ethanol causing lower RPM @ WOT?

Hi:

Last year when I winterized my '72 50 hp Evinrude, it was running perfectly.

This week I took it out for the first time this year. Filled the tanks with 10% ethanol gas that we now have.

Boat took significantly longer to reach plane, ran about 400 fewer RPMs less at WOT than last year, and I'm sure top speed was affected a couple mph, too.

I'm suspecting the ethanol. Gonna find a retailer who sells the unblended fuel (REAL gas) and try a tank of that to see if it returns my engine to it's former performance.

Pulled plugs and they look dark and a bit wet. Gonna replace them.

I'd appreciate your thoughts and experiences.

For the record....what are the chances that 1 6 gal tank of ethanol has fouled my carbs with dissolved rubber gunk?


Thanks!

from what i've read/understand the ethanol gas does decrease rpms/performance ....i personaly never seen a diffrence... i have a 1989 120 J

chances? is the tank, hoses etc new? then you probably are ok.... if you havent run the boat since last year i would def do a decarb(follow the link bellow)... good luck

 

[junior1113]

Re: Ethanol causing lower RPM @ WOT?

what is current wot rpm? 400 sounds like a lot 150 would be more like it.

 

[iwombat]

Re: Ethanol causing lower RPM @ WOT?

Hi:
For the record....what are the chances that 1 6 gal tank of ethanol has fouled my carbs with dissolved rubber gunk?

It's more likely that it dissolved some older lacquered gasoline in the lines/filter/pump/carb and clogged up a main jet. That's a pretty common event when switching to ethanol. Run another tank full, then replace the old lines if they're not ethanol resistant, replace your fuel filter, and clean out your carbs. Might want to add some seafoam to further dissolve any chunks of old dried gas in the short-term too.

 

[DGartzos]

Re: Ethanol causing lower RPM @ WOT?

Use paint thinner based on toluene or xelene or a mixture of both. It does spot clean areas where carbon deposits, especially o-rings. Mix 1/3 thinner 2/3 gas before oil mix. One tank should do it, once a year (running the motor on this continuously loosens everything inside).
Try not to get addicted to the nerve your engine will demonstrate.

 

[countvlad]

Re: Ethanol causing lower RPM @ WOT?

Use paint thinner based on toluene or xelene or a mixture of both. It does spot clean areas where carbon deposits, especially o-rings. Mix 1/3 thinner 2/3 gas before oil mix. One tank should do it, once a year (running the motor on this continuously loosens everything inside).
Try not to get addicted to the nerve your engine will demonstrate.

never heard of this one before.. but i guess theres always a first time...

anyhow if you plan to decarb your motor follow the link below... good luck

 

[Giz_]

Re: Ethanol causing lower RPM @ WOT?

Update:

I popped in a new pair of plugs, then found a gads station that still sells non-ethanol fuel.

Result:

Engine is back to normal WOT, or maybe a bit more.....I pulled the throttle back at 5650 RPMs.

Could just barely make 5000 RPM with the ethanol gas.

No more of THAT crap for me!

Thanks for all the suggestions.

 

[wilde1j]

Re: Ethanol causing lower RPM @ WOT?

Ethanol DOES PRODUCE less HP and RPM. Why, you might ask. Simple ... heat energy per gallon is a lot lower than gasoline. This is exactly why my boat will not see any more ethanol, now that a local marina has no ethanol gas, even at $0.30/gal more, the power and mileage benefits are worth it, plus no more water worries!

 

[Logos]

Re: Ethanol causing lower RPM @ WOT?

Out of curiosity, what was the octane on your ethanol-free gasoline???

I'm currently struggling w/this ethanol question myself.

 

[wilde1j]

Re: Ethanol causing lower RPM @ WOT?

Octane has nothing to do with it. Higher octane has NO more energy per unit volume. 87 is fine for 99% of outboards.

 

[Logos]

Re: Ethanol causing lower RPM @ WOT?

That wasn't the question.

On another thread someone indicated that higher octanes could cause problems in older engines, so if you used ethanol-free gas of a high octane you could run into new problems.

I haven't been able to coax any elucidation out of that poster, so I'm still trying to learn more on the ethanol/octane questions.

 

[wilde1j]

Re: Ethanol causing lower RPM @ WOT?

Higher octane fuels are not recommended for most non-racing outboards BC additives not present in 87 tend to form deposits, which are not good for engine health. Ethanol has no bearing on this at all, other than it's proclivity to attract water, which is bad for all motors. Again 87 (non-ethanol if you can find it is best). Ethanol also tends to dissolve some soft fuel system components in only older motors, especially, such as fuel line, gaskets and diaphragms. Clearly, that is not good. The only saving grace is carbs tend to be pretty tolerant of very small particles and just pass them through to be burned with the fuel. Not so for the new DI motors. Ethanol is a disaster here, since the fuel systems are open loop control, with no adjustment for most should an injector fouls. The hole just fails catastrophically.

Ethanol is just a very bad motor fuel for most applications and the greens fail to point out that it produces aldehydes (formaldehyde is just one) that are well known carcinogens. BTW, the more ethanol in the mix, the lower the power developed, since the specific energy off ethanol is considerly lower than gasoline or diesel, which has the greatest heat content of the common motor fuels. So much for ethanol!

Higher octane and ethanol together don't do anything different than lower octane fuels with ethanol, other than as pointed out above.

BTW, this is not a high paying job!

 

[Logos]

Re: Ethanol causing lower RPM @ WOT?

Thanks for the response.

When I called around about ethanol-free gas, they all mentioned higher octanes like 90, 91 and 92.

So, which is the better choice for a 68 model Evinrude with at least some but maybe not all new gas line components?

Higher octane ethanol-free?

Or the normal 87 octane with at least ten percent ethanol and maybe more depending on how honest the suppliers are???

Which is likely to be the better choice?

 

[wilde1j]

Re: Ethanol causing lower RPM @ WOT?

The lowest octane over 87 ethanol free would be my choice. This is not that complicated.

BTW, gasoline suppliers are not very likely to add any more ethanol than they have to, since it costs more than gasoline, (even though it's crap).

 

[jpwade_bsu]

Re: Ethanol causing lower RPM @ WOT?

Update:
....
Result:
....
No more of THAT crap for me!

GIZ, well said! , I have as much confidence in Ethanol as I do in the oil companies.

Your perspecitve reminds me of the days we changed from leaded to unleaded gas, what a pile of crap that was then too. Its a bummer to keep getting our fuel density jacked, how I miss the days of White Gas.

 

[Mac3]

Re: Ethanol causing lower RPM @ WOT?

I have a 98 Johnson 150 ficht and have been chasing a code 37 water in fuel for some time, I am pretty sure that after going around the block there is, if not water, fuel contamination causing this code and I suspect ethanol or ethanol attracting water. So I am about to fit a 10 micron fuel filter which I'm told will stop water and ethanol. Perhaps this might fix Giz's problem? Are you guys saying that high octane premium fuel does not contain ethanol? If so, I'll start using that if that's the easy fix.
btw I am writing from down under so things may be different here.
cheers
David

 

[wilde1j]

Re: Ethanol causing lower RPM @ WOT?

I have a 98 Johnson 150 ficht and have been chasing a code 37 water in fuel for some time, I am pretty sure that after going around the block there is, if not water, fuel contamination causing this code and I suspect ethanol or ethanol attracting water. So I am about to fit a 10 micron fuel filter which I'm told will stop water and ethanol. Perhaps this might fix Giz's problem? Are you guys saying that high octane premium fuel does not contain ethanol? If so, I'll start using that if that's the easy fix.
btw I am writing from down under so things may be different here.
cheers
David

No! In most states, all gas has ethanol, octane makes no difference. Yes, in Oz it may not be the same. You should have had that 10 micron filter from day one.

 

[Fistful]

Re: Ethanol causing lower RPM @ WOT?

This is an interesting thread. I have a 1987 48 hp johnson (2 cycle pre-mix) which has been experiencing carb clogging issues for the past few years. I treat every tank with Marine Sta-bil, use 87 octane (unfortunately 10% ethanol), and mix with Amsoil 2 cycle marine. My marine mechanic said he is recommending his customers with older model motors to use only premium (89, 93 octane gas). He said it runs much smoother and avoids the ethanol issues...I thought it sounded a little fishy.

From these previous posts, do I understand this is not advisable?

Also, I treated my current fuel/oil mixture with the recommended amount of Sta-bil for winterization and ran through the engine. Will this mixture be ok for use in the spring? The mechanic recommended I chuck it.

Thanks for your input guys.

 

[ondarvr]

Re: Ethanol causing lower RPM @ WOT?

Ethanol is not my favorite fuel additive, but it gets blamed for everything under the sun and is the real cause of very few problems.

Cleaning the fuel system is its most frequent side affect and that's only when first using it, power loss and water in the fuel are possible, but rarely an issue caused by it. I?m not saying this problem wasn?t related to bad fuel, but the ethanol probably had nothing to do with it.

I say this from many years of using it, we were one of the first parts of the country forced to use blended fuel more than a decade ago. There were many reports of clogged fuel filters and engines running rough at first, but after a short time the complaints went away and the subject of blended fuel was dropped for more important issues.

If you don't have a good fuel/water separator, you should buy one today, it makes no difference what fuel you use. If your engine?s fuel system is old enough to not have alcohol resistant components, then its long over due for a rebuild, so do it whether you think it needs it or not.

Each time a new section of the country is forced to switch to blended fuels this subject comes up and the people there think their world is coming to an end and the engines using it will all be destroyed. With very few changes in your normal habits you will never notice the change.

 

[Fl_Richard]

Re: Ethanol causing lower RPM @ WOT?

A 10 micron filter will not remove Ethanol. It wil remove most of the crap that Ethanol cleans from your fuel system.

You'll need a 10 micron water seperating filter to remove the crap and the water.