Hey Old

Liquid_wrench · Jan 13, 2018

Rich,

I was plowing snow this morning with our 1966 MF-135 (Continental Z-145 gas)and for some reason,i had to pull the choke 1/4" out to keep it running for 3 hrs,i've never had to do this ever....what gives? I just filled it with 93 octane and a can of seafoam...it was 8 degrees when I started it...I know it's not the cold...it's ran like a top in - 10-15 temps plenty of times.
Anyway I figured you might point me in the right direction. Thanks

Keith

old · Jan 13, 2018

Try opening up the main jet adjustment 1 or so turns out. When it is cold engines seem to like bit more gas to run well

jon f mn · Jan 13, 2018

Likely the 93 octane is just burning too cold for that temp. The higher the octane the cooler it runs and the less power it will produce. Your engine is likely just trying to compensate for the cooler burning fuel. You should be using regular gas. That is unless you have modified your engine with higher compression, timing, and/or cam work.

David G · Jan 13, 2018

Why would you put 93 octane in it?

Liquid_wrench · Jan 13, 2018

Rich,

I'll go out in a little bit and see if that helps. Thanks again!

Keith

Liquid_wrench · Jan 13, 2018

Because it don't like 87

Liquid_wrench · Jan 13, 2018

Jon,

Back in 1966,when this tractor was built....regular leaded fuel was 93 octane,99 octane for premium and 102 octane for high or super premium. This tractor does not run well on 87 octane fuel.....trust me....lol

old · Jan 13, 2018

By the way the higher octane stuff is not needed and will also cause you problems like your having. So again that leads me to having it running a bit to lean and choking it makes it run richer

Liquid_wrench · Jan 13, 2018

Rich,

I can see I'm not gonna win the octane battle...lol But anyway, I have used 93 octane in this tractor for many years now and never had a problem....maybe that 16 oz of seafoam to 10 gallon fuel was too much?

David G · Jan 13, 2018

So no science behind it.

Steve@Advance · Jan 13, 2018

The Seafoam could have contributed. It is a flammable petroleum product, and about 25% isopropanol alcohol.

Not sure what the BTU rating of the petroleum blend is, but the alcohol is much lower than gasoline.

So, the combination of diluting the fuel with Seafoam, the ethanol already in the gas, and the cold air, (which is denser and requires more fuel to get the ratio right),and a possibility the main jet may have picked up some trash or deposits, can easily add up to the mixture needing to be adjusted.

How is the engine temperature? Thermostat may be leaking by, doesn't take much when it's that cold.

old · Jan 13, 2018

About the only advantage I could see you from the 93 octane is the fact it may not have alcohol in it. Ya to run the cheaper stuff you do need a hotter plug

Russ from MN · Jan 13, 2018

I think you need to adjust the carburetor a little, if that doesn't do it then it needs cleaning. According to tactordata that engine is only 7.1:1 compression ratio, there is no way it need high octane gas.

Liquid_wrench · Jan 13, 2018

Rich,

Well you were right...I turned the main jet screw open about 3/4 turn after engine was warm...increased throttle to 1500 rpm,i stopped turning when I could hear engine smooth out,then went out and plowed for 30 minutes and with no choke it's running good again. Thank you Old and everyone for your help.

Keith

old · Jan 13, 2018

Winter and cold temps call for more fuel. The tractor I run this time of year get the carb adjusted on them twice YEAR SOME Time more due to the weather

JD Seller · Jan 13, 2018

rohdog50: The reason your need to run with the choke out is the colder air is more dense. So your able to get more oxygen into the motor in colder temperatures. Thus you need more fuel in to make the mixer not be lean. This is a major issue with tractor pullers. Air temperatures effect the amount of fuel or water you inject into the tractor to have maximum HP/RPM. Go to a tractor pull that is later in the fall and watch some of the fellows having trouble getting off the line. Their tractors are too lean to get the fire going like they are used too in hot weather.

I am not sure but if I remember correctly some of the older airplanes were set up to where you could adjust the mixer while in flight. They had the air density problem due to altitude and temperature.

As for running the better fuel. I can tell you the majority of the gas tractors and small motors around this part of North-Eastern Iowa will not run very well on the lower octane, ethanol added, 87 fuel. It must be regional as many fellow say theirs runs like it was new again on the lower grades of gas.

Hoenes · Jan 13, 2018

Agreed. I got some blue "jet A" from a friend one time , and ran it in my WD. Man it ran good. Got a little warm though.

Liquid_wrench · Jan 13, 2018

JD Seller,

This tractor is 52 years old,i really don't use it that much....maybe 40 hrs a year the 87 octane fuel here(northern ohio)goes bad in 2-3 months,which is another reason I run 93 octane fuel and seafoam as a fuel stabilizer.I have other newer gas equipment that runs fine on 87 (2 cub cadet riding mowers,pressure washers,generators,airless paint sprayers,1-ton truck....etc) But again they may sit for months without use....and for that reason and my piece of mind,all my gas equipment gets 93 octane with seafoam mixed in. I have done this for well over 10 years now and have had 0 problems with fuel going bad and carburetors being pluged up.I just sold our old 1974 ford F700 farm truck last year,it had the 361 HD motor....it ran like crap too on 87 fuel so we had to run 93 octane in that one too.....like I said before,on these older gas motors,they were made to run on 93. Our fuel here isn't the greatest.......lol

old · Jan 13, 2018

One of the reason the 87 octane gas goes bad is because of the alcohol in it that absorbs water and then evaporates and leave the water behind. The higher octane gas does not have the alcohol or is less likely to so it stays good longer

Liquid_wrench · Jan 13, 2018

Yes you are right

Hey Old

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