85 hp yamaha 2 stroke not cranking when cold out side.

[jaglenn1999]

I have a 85 hp Yamaha 2 stroke that will crank and run when it’s above freezing but once it gets 28 and below I can not get it to crank up. Has spark, compression, and good fuel. Can spray starting fluid in it and still won’t crank. Does anybody have any ideas on what it might be thank you!

 

[racerone]

Charge the battery and load test the battery.

 

[99yam40]

crank and start are 2 different animals

 

[airshot]

So...is it no crank or no start ??

 

[Scott Danforth]

Motor spinning fast enough? About 250 rpm?

 

[jaglenn1999]

Charge the battery and load test the battery.

Tried different batteries that were charge also used a jump pack on it

 

[jaglenn1999]

So...is it no crank or no start ??

Won’t start

 

[racerone]

Take starter apart and inspect it.

 

[airshot]

Won’t start

So the engine is turning over but won't fire up and run ??
Get a spark checker ( cheap at most auto stores) and check strength of spark if there is any ....

 

[racerone]

When it is cold , crank it over with sparkplugs in.----Can spark jump a gap of at least 3/8" on a proper spark tester , yes or no ?

 

[jaglenn1999]

So the engine is turning over but won't fire up and run ??
Get a spark checker ( cheap at most auto stores) and check strength of spark if there is any ....

Has spark

So the engine is turning over but won't fire up and run ??
Get a spark checker ( cheap at most auto stores) and check strength of spark if there is any .

 

[jaglenn1999]

Has spark

Video is from this afternoon. I will get another video once it gets cold again

 

[99yam40]

for the motor to start and run the cylinders need to have good compression, good spark at the correct time, and the proper fuel to air mixture.
when it is cold and will not fire up,chack comroession, check spark, check timing with a timing light,
if all that is good then you are left with a fuel to air problem.
does this motor have a choke or the Yamaha Prime start fuel enrichment system?
and what are your starting procedures?

too much fuel or too little can be a problem

 

[airshot]

So it turns over and starts, just won't keep running !! You will need to do some testing to check in the health of your engine. When you have those test results, post them and we can go from there...

 

[wmgeorge]

I have a 85 hp Yamaha 2 stroke that will crank and run when it’s above freezing but once it gets 28 and below I can not get it to crank up. Has spark, compression, and good fuel. Can spray starting fluid in it and still won’t crank. Does anybody have any ideas on what it might be thank you!

Cranking is when the starter motor turns the engine to rotate, starting is when it is cranking and trying to start with good gas, spark and compression. How old is the gas, not enough octane to fire off when cold. Buy New premium non ethanol gas mixed with the correct 2 cycle oil at the proper ratio.

 

[garbageguy]

99yam said it well-the the laws of thermodynamics coming into play

in addition to getting chemical reactions to go, most materials change dimensionally with temperature - maybe a connection doesn't connect properly when its colder

 

[dingbat]

How old is the gas, not enough octane to fire off when cold.

Octane raises the ignition temperature (lowers volatility) of gasoline. Makes it harder to start when cold

Buy New premium non ethanol gas

Running premium fuel in a low compression (2 stroke) motor is a waste of money.

What purpose does non-ethanol fuel serve in this situation?

If condensation in the fuel is an issue, E10 will actually help the situation. Helps pass water harmlessly through the fuel system while cleaning the system in the process

https://www.epa.gov/sites/default/files/2015-09/documents/waterphs.pdf

 

[wmgeorge]

Octane raises the ignition temperature (lowers volatility) of gasoline. Makes it harder to start when cold

Running premium fuel in a low compression (2 stroke) motor is a waste of money.

What purpose does non-ethanol fuel serve in this situation?

If condensation in the fuel is an issue, E10 will actually help the situation. Helps pass water harmlessly through the fuel system while cleaning the system in the process

https://www.epa.gov/sites/default/files/2015-09/documents/waterphs.pdf

I do not know where you live but Never Ethanol gas in any small engine it can screw up the carburetor in as little as three months. Premium gas holds its octane rating over time as well as Stabil always in gas that is stored for long time over 3 or 4 months. Old gas will affect the starting and that is a known fact. Dump it out and put fresh. I have been doing this stuff for nearly 70 years and the only carbs I have ever had to clean was from someone else not doing as above. For the price of a gallon of the gas I referenced above he could solve his problem.

 

[airshot]

I do not know where you live but Never Ethanol gas in any small engine it can screw up the carburetor in as little as three months. Premium gas holds its octane rating over time as well as Stabil always in gas that is stored for long time over 3 or 4 months. Old gas will affect the starting and that is a known fact. Dump it out and put fresh. I have been doing this stuff for nearly 70 years and the only carbs I have ever had to clean was from someone else not doing as above. For the price of a gallon of the gas I referenced above he could solve his problem.

Been using E10 since it came out, not one issue ! Watch where you buy your fuel !! Just took out my snowblower, drained out last years ( 11 months old) fuel from last year and it looks just like the new fuel !! Put the old gas in my small generator and it fired right up and ran perfect for an hour till I shut it off. Your buying bad gas to begin with, find another place to get it.

 

[wmgeorge]

Been using E10 since it came out, not one issue ! Watch where you buy your fuel !! Just took out my snowblower, drained out last years ( 11 months old) fuel from last year and it looks just like the new fuel !! Put the old gas in my small generator and it fired right up and ran perfect for an hour till I shut it off. Your buying bad gas to begin with, find another place to get it.

LOL Looks have nothing to do with it! My friend who owns the hardware store on the North side Loves Ethanol! His lawnmower, snow blower etc repair shop says if it wasn't for the stupid homeowners using it they would be out of business. I don't buy or use it except in my car or pickup so I would not know about Bad Gas. Never in a small engine. Been doing this for a long time as I posted above, never and issue... Just one of many sources I found online to educate yourself > https://www.consumerreports.org/cro...ethanol-can-make-small-engines-fail/index.htm