Power lose due to extreme cold?

[allwheeldrive]

Has anyone ever noticed a significant amount of power lose in their small engines before due to extreme cold?

It has been abnormally frigid the last two weeks in VT with mid day temps around -10 and at night in my valley -30

I know internal combustion engines become less efficient and thus I assume make less power in this level of cold. My truck is only managing 6mpg (normal 19) after I let it warm up. The 8hp Brigg and Stratton in my Quadractor starts right up and runs smooth despite the incredible low temperature. However even after letting it ideal for 10min it can hardly get out of its own way. Previously I could bomb around in a foot of snow in 2nd gear (38:1 gearing) and only bog the engine on steep climbs. Now I can’t even reverse without stalling the engine (unknown ratio) and it struggles in 1st (72:1) to make any progress. It feels like I only have ¼ of the hp or less. Maybe this is compounded by stiff rubber belts sucking up a lot of energy and the grease in the hubs must consume a lot of power to turn as well. Otherwise I wasn’t aware it be this severe of power lose.

[john swenson]

i'm sure the belts and grease do contribute somewhat to power loss. also what oil viscosity are you running ? maybe someone will suggest the best weight oil for those temps. johnboy va. p.s. i haven't noticed any difference in my max 2 21 h.p. vanguard..but that's a big difference in h.p. than your 8 h.p.

[Craig_B]

Could also be the viscosity of the gear oil in the gearbox.
I have heard it suggested to use synthetic oil. I have 75W90 synthetic in mine.
The engine will eventually heat up the motor oil but not much heats up the grarbox oil other than friction.

[allwheeldrive]

All good points. Today it is sunny and 20, a BIG difference from a few days ago. I'll try and see how it runs when I get home. It very well could be the grease in the portal axles that slows the machine in extreme cold more than engine power. They are 4 big gear boxes and that combined effort might be a lot. As has been mentioned they aren’t going to warm up quickly and if they did that would mean I wasn’t having any trouble spinning them in the first place.

When I bought the machine, the previous owner (the chief engineer at the old company from back in the day) he refilled all 4 portals. He told me they were originally made for oil however they leaked quite a bit and all that oil would just end up on the ground. Thus for the past 30 years he’d just packed them with grease. I trust his judgment, if anyone knows how to keep these machine running it be him. My machine is a testament to that. He told me he used “red snowmobile grease” I’m not quite sure what that is. At some point when the machine ends up submerged in mud and water next spring I’ll take the time to open her up and replace the grease myself to check for leaks etc. I am in the opinion “corn head grease” would be most ideal for this application. It may not be the best choice in cold, but it has very interesting qualities sounding very fit for this application. Intended to replace oil in super high shock load, slow rotation high torque gearboxes including worm gear boxes. I’m tempted to try it in the Coot’s gear boxes but don’t want to risk it just in case.

[onefunzr2]

I'd say the below zero temps combined with that sluggish grease and only 8 horsepower is your problem. Internal combustion engines are heat pumps. If you can fashion some sort of shroud to keep the heat from being sucked out into the great outdoors, that might help. Like the over-the-road big rigs who fasten 'winter fronts' in front of their radiators to keep more of the heat in the cooling system. Of course, the biggest help would be if you could keep your AATV in a heated area when you're not outside running it. That would soften all the grease.

[Noel Woods]

I think the viscosity issue is the culprit. I've noticed on my vehicles difference in running 10w30 vs 10w40 oils and I don't live in an area with your temperature extremes.

[Craig_B]

Could the carb be freezing up?
I have ridden my motorcycle when the temps where just above 0C and the engine bogged down real bad.
When I looked down at the carbs (4) they where all frosty. After the bike had idled a while they thawed out and I was on my way again until they frosted up again.

[john swenson]

just to share, when i read the history on the developement of the ''quadtractor'' the guy that designed them was previously designing and building landing gears for planes. that's why the 4 tall legs and wheels look so familiar. he incorporated them in the idea for the '' quad'' in order to get the high clearance. johnboy

[allwheeldrive]

lot of good suggestions. I hadn't thought of carb icing. That was a problem with the Model-T if I recall, they devised a heated hot-air intact device for extreme cold (granted hot air is going to make less power and it did, however less power was better than no power in that case lol)
I did notice icing, icing everywhere! Including on the engine even while running.

Storing the machine in any sort of enclosure would greatly help, in fact that pretty much alleviate all of my problems. Alas no garage! )-:

I'm going to assume it was sluggish grease, or a combination of the above. I also notice the belts are less bity again likely due to the cold on their rubber. I had it out last night (video card had an error and lost video, maybe from cold to )-:<
It ran like a champ. Was much warmer 17 degrees. If I can't drive it in -15 I guess its not the end of the word.