TRUE? I have to burn ethanol, retard timing?

[audiobill5]

Great forum!
Opinion poll time:
An outboard service yard told me on my 1972 50 hp Johna/Rude fishin' mota, that runs on E10 (all we can get in Massachusetts) that I should not run at the stock timing setting of 19 degrees @ 5500 RPM: I should time to a setting at least 2 degrees less to have the engine hold together longer.

Is this fact or fiction?

Would the change in timing even make a difference the way it performs?

Thanks,
Bill

[sabine river killer]

you need to use ethanol approved gas hoses and check the jetting and retarding the timing will cause you to loose some bottom end power but i do not know if you need to do that or not the ethanol is very new to me and am old school

[Aeroliner]

Over this past year we have been using up to 10% ethonal in our racing fuel with the NBRA. So far there have been zero issues with our engines or the fuel for that matter. We normally time our 4 cylinder mercs at .365 and have not changed that for this new fuel requirement. We do run a slight bit richer with the blended fuel. The additional of ethanol actully increases the octain a slight amount.

Alan

[Mark75H]

The additional of ethanol actully increases the octain a slight amount.

Which allows them to reduce the quality of the base gasoline stock. 87 at the pump is 87 regardless of whether it has ethanol or not, same for 89 and 92/93.

If the ethanol was being added to finished 87, then it would increase the octane ... but the gas companies know they only have to meet spec on the finished product ... some states let them get away with below grade sales - other states actually test samples and fine stations selling below grade.

I would not change the timing on a motor like a '72 50 hp twin.

[microbream]

definitly check fuels hoses to see if they are compatable to ethanol.
You should not have to retard timing, however expect less bang for you buck, ethanol has a much lower energy rating than gasoline. I won't use the stuff anymore, for the cost saving it is just not worth the fuel economy reduction IMO.
Here in oz we have the choice of 4 fuels. E10 (10% ethanol 90 octane), unleaded (90 octane), Premuim unleaded (95 octane), and super preamium (98 octane).
I ran E10 on my new model merc (service manual said it was ok).
Now i run 95 on my suzuki but is has 190 psi compression.

[fs5]

ehtinol loves eating out your primer bulbs and clogging your needle and seet in your carbies with the disoved rubber.
been there a couple of times with my merc.
as long as all your fuel lines / fittings can can handle it ,i don't reckon it hurts.don't let it sit in your tank for too long either ,it can sludge up in a month or two.keep it fresh .
it won't be long and we'l all have to run it ,even over here....

[audiobill5]

So can I run bigger than #58 jets and advance it a couple degrees if I run e10 fuel but 92 octane?
Thanks

[Bill Gohr]

Well in you've been running alcohol laced fuel since the mid 80's, the amount of it was based on the state laws so.......

The other scenario is remember the easiest way to increase octane is to add alcohol so alot of some fuel's high octane fuel may have more alcohol than others.

So, the best thing to do is buy name brand fuel and go with the mid grade is commonly is the best quality fuel and has the chance to have the least amount of alcohol.

As well, lowering th etiming 2 degrees is not a bad idea, and you probably will not feel a loss of performance but the motor will know the difference.

In the 80's we had a chart that listed what motors needed to be detuned for alcohol laced fuels, some got thicker head gaskets, some got reduced timing but I don't think we said to do anything to your engine.

[Aeroliner]

Well lets go back in history. Mercury produced the 75-H with a flywheel marked for gas and alky. If I remember correctly the gas mark was 40 degrees before TDC and the alky mark was set at 44 degrees. With the small amount that is currenly added to gas I would keep the timing at factory spec. As Sam stated you really don't know how the fuel is blended but if the octain is what the OEM recomends then I would not change it.

Alan

[quick2008]

Having a read here..and Just a general quesiton,
Im assuming that Methanol has a lower BTU rating than regular gasoline?

[Mark75H]

That is correct, but there are many other more important factors.

Exactly where are you going with the methanol idea and why have you brought up a third fuel?

[DuckLn]

I can say this about Arkansas filling stations: Our state regs are not sufficient and that is all i will say.

[microbream]

Methanol has a 50% lower BTU than gasoline, however the ideal methanol/air mixture is 1:5.5 which is more the 2.3 times fuel than if gasoline(1:13) is used, thus the heat produced is approx 17% more than petrol.
Ethanol is about 10% more than petrol.
flowing that amount of fuel requires a serious rejet though!

[microbream]

Adding ethanol to petrol will increase its octane number which allows you to run higher compression and advanced timing, For a while here in oz you could get cheap 95 octane E10 ethanol blend which was good in my opinion. But since then they have blended ethanol with lower grade petrol to give 90 octane crap IMO. Low fuel economy and poor power is hardly enviromentally sound!

stick with plane old high octane gasoline unless the ethanol added actually gives some octane advantage. We also had a 100 octane fuel available breifly which used ethanol to boost it octane number up, was popular with the turbo boys.

I guess the long and the short of it is, no, you should not have to retard timing if the octane number is as specified in your owners manual, regardless of what the fuel is blended from.

[Tim Kurcz]

Product Latent Heat of Evaporation (kJ/kg) / (Btu/lb)

Acetone 518 / 223
Alcohol, ethyl (ethanol) 846 / 364
Alcohol, methyl (methanol alcohol) 1100 / 473
Toluene 351 / 151
Water 2257 / 970.4

Here's why you want to run Methanol!

[microbream]

Becareful here, latent heat of evaporation refers to the amount of heat to convert from liquid to gas. and i quote:
Methanol and ethanol have a very high latent heat of vaporisation, i.e., it takes a
lot of heat to convert them from liquid form into vapour. Petrol has a latent heat of
evaporation of 135 Btu/lb., methanol 472 Btu/lb. and ethanol 410 Btu/lb. This heat,
required for proper atomisation, is removed from the piston crown, combustion
chamber and the cylinder, resulting in an internally cooler engine.
An engine burning methanol will usually show a 6-8% power increase over one
running on Avgas 100/130 (i.e., Racing Fuel 100), without any change in compression
ratio. With the compression ratio increased to its maximum, power can rise as much as
15-17%. Where does the power increase come from?
The two cycle engine is a type of heat engine, i.e., one that burns fuel to cause the
expansion of gas, and the subsequent movement of the piston. The more heat produced
by the combustion fire, the more pressure there will be exerted on the piston, which
gives us a power increase.
Using petrol, the fuel/air ratio for best power (i.e., the strongest force on the
piston) is 1:12.5. With methanol, for example, we can increase the fuel/air ratio to
1:4.5, although I usually prefer a ratio of 1:5.5; less than 1:7 is too lean.
One pound of petrol has the energy potential of about 19,000 Btu (one British
Thermal Unit is the amount of energy required to raise the temperature of one pound
of water one degree Fahrenheit.). In comparison, methanol delivers around 9,800
Btu/lb., which means that it produces less than 52% of the heat energy of lib of petrol.
However, because we are mixing more methanol with each pound of air (1:5.5) than
petrol (1:12.5), we are actually producing more heat energy by burning methanol.

[Fastjeff57]

Wanna go like a bat outta hell? Inject WM50 (water/ methanol 50 %) into the carb opening at full throttle. Virtually every WW II aircraft engine builder used that trick to prevent detonation, so they could run higher boost pressure and/ or compression ratios. The water and methanol effect the cooling without need of extra fuel, which you WOULD need with pure methanol. Far as I can determine, no fuel enrichment was ever added with the WM50, just the juice itself.

All you need is a tank, a windshield washer pump, a nozzle and some plumbing. I did that on several of my turbo cars running insanely high boost pressures, using a pressure switch to trigger the pump.

Jeff

[Mark75H]

Do you think spraying water into your bearings is a good idea?

[OUTBOARDER]

Great forum!
Opinion poll time:
An outboard service yard told me on my 1972 50 hp Johna/Rude fishin' mota, that runs on E10 (all we can get in Massachusetts) that I should not run at the stock timing setting of 19 degrees @ 5500 RPM: I should time to a setting at least 2 degrees less to have the engine hold together longer.

Is this fact or fiction?

Would the change in timing even make a difference the way it performs?

Thanks,
Bill

one gallon of BLUE THUNDER 30% NITRO / 70% Alky mixed with 5 gal 10% alky pump gas.
replace main jets with #70's set timing to 24 deg btdc you will notice it, get a big prop while your at it!

[Bill Gohr]

Wow glad this thread didn't run off on a different tangent

[quick2008]

That is correct, but there are many other more important factors.

Exactly where are you going with the methanol idea and why have you brought up a third fuel?

Apologies Sam,
There was something mentioned a post or two back about mixing alky with gasoline..
and the BTU's of Alcohol came to mind, I probably should have written "ethanol" instead of throwing meth in as a third.
My Bad :)