I feel like I need to give the full background to what happened so far.
i bought the backhoe, the guy said it overheats when you use it for a little while, and I will know because radiator cap area will smoke. I brought it home and it worked fine..this was like a week ago.
I used it to dig some holes and flatten things etc. At some point, I think the backhoe overheated and it started to sound horrible and lose power. I also saw white smoke from the tube on the left side (I believe it did its the crankcase vent?). It also started spewing coolant out of the top hole when I turned it off. I did some research and it suggested a blown head gasket do I used a additive in the radiator that fixes the head gasket.
As I was reving that through, the backhoe shut off. I couldn't turn it back on. Turned out to be the batteries. So I charged both batteries and it worked again. The sound went away and it wasn't overheating like before. And less white smoke. I did touch the carburetor knobs at this time because to start it up I would need to pull the choke in and out and in and out while holding the key dow. to get it started. This wasn't the case when I brought it home.
I changed the crankcase oil with 10w30 at the suggestion of the auto shop guy, but thought this might be the issue so I changed it back out to SAE 30, which seemed to help a little bit. I haven't drained and refilled the radiator since it isn't losing coolant anymore.
Seems there's a lot going on here.
The overheating - I would not run this machine without a temperature gauge. Frankly, I wouldn't run any machine of this complexity and cost without a temp gauge. But that's especially true for one that has known cooling issues. Waiting for signs to show up is asking to cause damage. It is also possible that a loose cap will cause a little bit of steam before things are actually too warm, and you may not have an actual overheating problem. You have no way to know unless you are measuring the temperature directly.
The head gasket - additives (IMO) are a last ditch effort to correct an issue that you are unwilling to fix correctly. If there is a head gasket issue on say, an older car, it might not be worth the cost of fixing directly. So that additive might be worth a shot to get a little bit more life out of something that might be going to the junkyard. But it can reduce cooling efficiency if it plugs or coats the wrong area. I am not sure you had a head gasket issue at all, to determine that you need more diagnosis than is written above.
The carburetor - do you have experience adjusting carburetors? Often times there is a procedure to do this, and it's not something to mess with without the appropriate tools and knowledge of what the adjustments do. Running an engine with an incorrect mixture can cause degraded performance and sometimes cause damage.
The Oil - I don't buy that you can notice a difference between 10w-30 and SAE 30 from the operators seat. Winter starting would probably be improved with 10w-30.
The Hydraulic oil - you need to drain from every drain plug, not just one. I think there might be 3? But I don't remember specifically.
The batteries - It sounds like maybe they aren't charging. But that would need to be checked with a meter.
I wonder if you'd be well served to find someone in your area that knows their way around equipment to take a look at this for you. Seems there are many things going on, and a little time with someone that knows equipment would likely be of great value for you. I would have them install a temp gauge, look over the rest of the machine, and go from there. We can try to help from the internet, but you may get sent in the wrong direction, and even amongst those that know, being with a machine physically is tremendously more valuable than trying to diagnose one through a keyboard.
