cub doesn't like to start in sub-zero

Anonymous-0 · Jan 11, 2009

I've got a 1951 Cub that we use for snow plowing. If temps are above 30*F, it starts w/ no trouble & works fine. If colder than that (most of the winter here in Maine), it is VERY hard to start & when it does, it puffs & billows black smoke for a while. I checked my carb & installed a rebuild kit, spark plugs are not fouled, battery & cables are good. Is this a carb issue? I added some dry gas & it didn't help. Ideas? <a href="http://s464.photobucket.com/albums/rr4/kennebunksawmill/?action=view&current=cubplow002.jpg" target="_blank">

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glennster · Jan 11, 2009

my cub doesnt like to get going in the real cold either. if you have a torpedo heater, get the carb side of the motor warmed up a little, seems to help the fuel vaporize a little easier. other thing is give er a quick shot of starting fluid down the intake stack first, then crank it over.

Rudi · Jan 11, 2009

Did you winterize the Cub? As in, did you change the oil from say straight 30w to 10w30 etc..? Some have to and some don't. Cub's don't much like cold thick oil, so you can get an engine warmer -- like a battery blanket. Some are magnetic and stick to the oil pon (don't know how good that is),

My Cub does start well in the winter and I do not change anything from summer to winter. Course I keep my Cub in a barn along with my other tractors. My Cub is on 6v 30 wt oil and she starts all the time. The only time she won't start in the winter is when she is left outside.....

If all other factors have been covered then most likely enclosed shelter would be the fix. It appears that your Cub is stored in an open ended shelter. Even it you just tarped the openings to keep the weather out. And a lot of warmth in......

Oldiron29 · Jan 11, 2009

Kenbunk,I have had the same problem with a cub.
Yesterday snow was comming so I went out to put the chains on and get her going. I have 3 cubs parked in same shed. 2 of them start with no problems the one with the snow plow would not. I ran battery down and had to charge it. I pulled mag cleaned points spark is good it seems to be fuel problem gas running out of carb but plugs are dry. I am going to pull carb today clean and change my plug. Mabe swap carb with other cub see if that changes anything. oldiron29

El Toro · Jan 11, 2009

You need to hold your hand over the throat of the carburetor and have someone crank over the engine with the starter and see if there's good suction on your hand. This will tell if you have good intake manifold vacuum. This is required to pull
that atomized fuel into the engine. If there's weak suction do a compression test and compare the readings. Worn cylinders, rings and valves
not seating will contribute to poor vacuum. Hal

El Toro · Jan 11, 2009

I would install a coolant heater in the lower radiator hose if you have room to preheat the engine. Hal

Anonymous-0 · Jan 11, 2009

You mite need to replace both hoses from the carb to the aircleaner as they could be leaking the vacuum when cranking and a hotter plug. That little 60 cu in engine should turn oover and crank easy. Have ya checked the aircleaner maybe it need a good clean-up. What is the compression?

GordoSD · Jan 11, 2009

The fact that it fires at first and then stalls, confirms that all the electricals are fine, and fuel is there. 5-20 oil probably won't cure it but might help a little.In your area anything outside should have 5-20 in it. Or synthetic.The problem, evidenced by the black smoke is that there is too much fuel there, and it's not being atomized properly.
Try this . Don't use any choke at all. Set the throttle control at about half. lean the idle side down a turn. If it starts and dies, shut the ignition off, open the throttle all the way and crank it over a few times. This will clear that excess fuel out of the chambers.
Then try the normall start again. It's flooding and you might cure it with a carb rebuild and leaning both the idle and load sides down. Turm em up when you get warmed up.
I had a 3010 that did this to me for two winters before I sent the carb to the JD expert of the universe, and that solved all my problems.

Gordo

Gene · Jan 11, 2009

Complete tune up?

mkirsch · Jan 11, 2009

Lighter oil will definitely help. Straight SAE10, or 10W30.

A lot of it has to do with technique, too, and learning what the tractor needs to start. Every tractor is a little different; my Super A needs only a single quick blip of choke, but my one Cub needs the choke set and left there until it starts to stumble, for example.

Lots of black smoke and dribbling carb means you're giving it too much choke and flooding it.

Try cranking and blipping the choke. The engine should pop, and you can then feather the choke to keep it running.

Dave in CT · Jan 11, 2009

Another thought, triggered by the accounts of black smoke, is to see if your float is closing. Before doing anything, pull the hose from the air intake off to see if gas runs out. If it does you're flooding by the float valve not closing. I haven't solved the float problem on my H so I shut the fuel off before I stop the engine using the valve at the sediment bowl. I would imagine similar issues would be possible on the cub. Once that's done the blipping the choke techniques described here tend to work a lot better.

Anonymous-0 · Jan 11, 2009

air cleaner. possibly freezing up from snow being pulled in when plowing melting from engine heat or warm day and setting in bottom of oil cup shutting off air flow. or heavy oil in oil cup, use 10 weight or 5w20 in air cleaner in winter. dad had a c in early 50's that he would drain oil cup completely in very cold weather so it would start for hauling hay rack from barn to cattle lot, about 1 load a week so not much time in maybe 2 months, put oil in cup and it would never start in near 0 temps.

Brownie 450 · Jan 11, 2009

The neighbor down the road always said to take the air cleaner cup & the battery inside the house with you in the winter to get the tractor started easily the next morning. Stands to reason-- warm oil in the cup heats the incoming air & gets drawn into the carb for better starts.

Oldiron29 · Jan 11, 2009

Hal, went out this morning temps down in the teens. Had charged battery last night. Turned on the gas pulled the switch and hit the starter and she fire right up. So I think I had flooded it yesterday, but I have had this problem before I will try to lean the carb. She ran fine after starting. oldiron29

barn E · Jan 11, 2009

Looks real good! Distributor, right? 6 or 12 volt? I got one and a couple neighbors have them, none start too good in cold weather. Course mine is kinda worn out. One thing if you have hydraulics don't touch that control till tractor is running. If its moved a little somehow it seems to slow down cranking. Also hold in clutch. Experimenting with magnetic heater this year. Let you know. As somebody said, ice can form in air cleaner hose due to velocity, humidity and low temps.

ste_fano · Jan 12, 2009

I have a cub that I have to play with the choke too when it is cold. Starts easy when warm out. It is kept under a tarp outside. Sat it was 19 degrees F, but finally got it started. Bought a magnetic heater for it Sunday,19 degrees too, put it under the oil pan for 1.5 hours, started easy. Other good ideas brought up here too. Steve

cub doesn't like to start in sub-zero

Anonymous-0

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