Adjusted the fuel/air screw now tractor won't start

[RedFred]

I just adjusted the fuel and air mixture screw to 1 1/2 turns out now the tractor won't start.

[Don McCombs]

Did it start OK before you made the adjustment? Does it not turn over? Turn over, but not start? Did you turn the fuel on? Give us a little more information so we can try to help you.

[RedFred]

It started fine before but always needed choke to star even if its summer and now turns over and starts sometimes but puts and puts for a few seconds then dies.

[RedFred]

It started fine before but always needed choke to star even if its summer but now sometimes fires then and a whole bunch of white smoke then dies

[inairam]

is it an IH carb or zenith? I find the zeniths need choke most of the time.

White smoke means there is coolant in the cylinder or there is a new pope. In this case, I think it is coolant in the cylinder.

[RedFred]

Its an after market IH carb

[RedFred]

and ps how would coolant in the cylinder if there wasent any before?

[Don McCombs]

Since your Cub is a 48, we’ll assume that it has an IH carb. Based on your symptoms, I would shut the fuel off and remove the main metering jet. It is the brass, hex head fitting on the lower, outside portion of the carb. Clean the small orifice with a piece of fine copper wire, like telephone wire. Before reinstalling the jet, open the fuel valve for 30 to 45 seconds. You should get a constant, generous flow of fuel out of the opening. If the flow is intermittent or just dribbles, you have issues upstream of the jet. If you have good flow, reinstall the jet and try to start the tractor. Let us know your results.

EDIT: I see you posted more information while I was typing. Did the tractor run fine with the aftermarket carb, or is this a new installation?

[RedFred]

I will try it thank you for the tip Don.

[RedFred]

I tried it and got it to run but it sputtered and died a few times before I got it going now white smoke comes out the muffler when I throttle it up then after I ran it for a bit then shut it off then tried to start it again and it didn't start

[RedFred]

Ps It did run fine with it before but it always needed choke to start even on the hottest days.

[PFord]

I'm not the expert here, but I'm wondering if it ran lean, got hot, and ruptured the head gasket. White smoke means coolant in the cylinders. A compression test should show up the problem.

Needing choke typically means the engine is running lean (possibly from poor fuel flow). Your initial post of fooling with the mixture screw makes it sound like you either had an issue, or something was going on.

It probably won't run now because coolant entering the cylinder(s) are drowning out the ignition flame.

[RedFred]

I'll check it out
and see

[Eugene]

Conduct compression tests.

[RedFred]

I checked the coolant level and it seems low i'm hoping the coolant was always like that.