My JD Zero Turn is not starting well in cold weather.

What kind of cold are we talking about. Below zero? Almost small engines start hard at that temp. Try a blanket and heat lamp for 20 minutes before starting or a magnetic block heater or small propane heater pointed at it. Once the block warms a bit it should start fine


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My bad boy always has to have choke to start. But I can turn it off as soon as it fires. It won't start with out it. It has the Kohler 747cc


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Do we really want to know why you are mowing the lawn in December??

I have a 757 zTrak with the 25hp Kawasaki v-twin. It is also hard to start in the cold. I just put a Reddy jet heater in the shed for 20 minutes to preheat, before starting in winter weather. A traditional block heater is not an option, since they're air cooled.

Warning, one year I couldn't service myself, so I paid the local JD dealer to come pick it up. While they were trying to cold start it (I wasn't home), they apparently blew out the breather. Every time I ran it after that, it would lose almost a quart of oil per mowing, until I was able to get around to pulling the flywheel and front engine cover to access and replace the breather. Can't say if your mower has a similar configuration, but it was a major PITA, so consider yourself warned!

I don't think there is a Kawasaki motor made that likes to start in the cold. Possibly magnetic block heaters on the Hydraulic tank & oil pan.

Provided you have good gas, clean filters and no cracks/holes that develop in cooler temps I'd say you have a choke or carb issue. Check to see if the choke closes all the way. If so then you may need a carb clean/adjustment. Using wd40 as starting fluid should tell you if you have a fuel issue. It may also be that the cylinders don't have the best compression and constriction from cool temps require some oil to really seal before firing. i run lots of zt's and small engines and they can be a bear to diagnose, but hard start at 60° isn't normal. Hope this helps.

Those temps shouldn't affect it at all.
I do fall cleanups and in the morning they will start even if it's 20 degrees. The carbed kawi was way harder to start then the Kohler efi, but it wasn't terrible.
Usually in September I switch to a lower weight of oil, 5w30 or lower.
Check fuel filter, and quality of gas. I only run 91 or 93 in my mowers.
Check air filter, spark plug etc.
55 degrees tells me there is something else wrong with it.
Clean cooling fins, if they have a lot of build up or crap on them it could be harder to turn the mower over.
Edit also make sure your battery has the correct CCA for your model. Not sure what engine you have but it could be part of the problem

What your plugs look like? I am leaning towards a Carb issue also.

Have you checked the throttle cable? It is more common in the break in portion of newer equipment, but sometimes the throttle cable can slip, causing your full choke start to actually be more in the running position. Not such a big deal in warm weather, but really affecting starting in cooler to cold weather.

Can't speak to the smaller JD ZTrak's, but on the commercial ones, throttle and choke are two separate levers / cables. You'd notice it running at less than full RPM if your throttle cable slipped, on the commercial mowers.

greg13 said:

I don't think there is a Kawasaki motor made that likes to start in the cold. Possibly magnetic block heaters on the Hydraulic tank & oil pan.

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Are these all Kawasaki motors? I would be very unhappy with that experience. My Husqvarna 61" has a B&S 28 HP (carb) and it starts fine at 35F. I often use it off season with a utility trailer. I use plain 30 weight. I wouldn't think a thin oil would be necessary or desirable at only 60F.

I've never had a Kawasaki powered machine, but I've never heard bad things about them. Another source of info you may try is https://www.lawnsite.com/. Lots of experts there.

Sprinter said:

Are these all Kawasaki motors? I would be very unhappy with that experience. My Husqvarna 61" has a B&S 28 HP (carb) and it starts fine at 35F. I often use it off season with a utility trailer. I use plain 30 weight. I wouldn't think a thin oil would be necessary or desirable at only 60F.

I've never had a Kawasaki powered machine, but I've never heard bad things about them. Another source of info you may try is https://www.lawnsite.com/. Lots of experts there.

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I don't think the issue is the motor. It's that the motor driveshaft has a live connection to a pump that's churning 45W oil. If your sled runs on low-viscosity hydro oil or ATF, you may not have this problem. But any Zero-turn mower with a live pump running 45W oil on the hydro pump is going to start hard in cold weather, whether the motor be Kawi or B&S.

Ashful said:

I don't think the issue is the motor. It's that the motor driveshaft has a live connection to a pump that's churning 45W oil. If your sled runs on low-viscosity hydro oil or ATF, you may not have this problem. But any Zero-turn mower with a live pump running 45W oil on the hydro pump is going to start hard in cold weather, whether the motor be Kawi or B&S.

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Just FWIW my ztr uses 20-50 for the hydros and the hydros are Hydro Gear ZT-3400 models. I get the point that all that would stress the battery's capacity for delivering enough juice to the starter to overcome it under extreme situations.

What kind of hydros are used in the OP's rig, and does it really need such heavy single grade oil? The Hydro Gear models are spec'd for 20-50. Maybe that's the difference. In any case, I can't imagine 55 or 60 degree temps should be a problem for any unit like this. Below freezing or so, sure, but 55 or 60?

Just for giggles, I stole a post from a thread in Lawn World just to show that there can be all kinds of cold start causes. Not saying this one is necessarily appropriate here, though.

"Re: Hard starting in cold temperture
I want to thank everyone for their input. When I went to remove the starter I think i found the problem.The 12v cable at the starter was not tight.Looking at it ,it appeared to be OK. When I went to loosen the nut it was already loose. I took the nut off , cleaned the connection and put the cable back on properly. This morning 30 some degrees it started up like it is supposed. The lesson here is to check the simple things first."

Not sure if the OP's Deere 425 is the same , but Deere 757 runs 45W90 in the hydro.

All engines require additional fuel to start when they are cold. So what's there cold starting procedure? Is it all working, choke, primer. etc.

xman23 said:

All engines require additional fuel to start when they are cold. So what's there cold starting procedure? Is it all working, choke, primer. etc.

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Yeah, my B&S is an automatic choke. That may make a difference, too.

One thing about this I may have missed: Is it a matter of very sluggish cranking, or does it crank normally but just doesn't start?

Sorry if I'm flogging a deceased equine here, but I just hate problems without a solution.

Ashful said:

Not sure if the OP's Deere 425 is the same , but Deere 757 runs 45W90 in the hydro.

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Just curious, but what kind of hydro does yours use? 45W90 seems pretty stiff to me (not that I'm an expert).

Sprinter said:

Just curious, but what kind of hydro does yours use? 45W90 seems pretty stiff to me (not that I'm an expert).

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Neither am I! No markings on it, other than a Deere part number.