I have a 1968 Ford 3000 gas tractor. This past week it has been difficult to start. Starter cranks fine but have to crank it six or eight times, and about the point I'm about to give up it takes off. Up to that point it cranks without any response. Once started, it runs fine. Before it always started on first crank. Ideas?
I don't know the specifics of your tractor but I'd check the spark first. Pull the center high tension wire from the distributor cap and holdit near a good ground and try a start. You should see a FAT, BLUISH-WHITE SPARK, the color of lightning. If you do then your primary ignitin circuit is good. Move on to the fuel system. If you see a spindly reddish blue or yellowish spark, you need to find out why. Check the points first. Look for oil, corrosion, pitting, burning, etc. Check the gap and make sure that is correct. Check the wiring for dirty and/or loose connections. You probably have a 12v system so you should not have a resisitor in the primary circuit. You might consider changing the condensor. What happens in the weak spark case is that all the fuel getting into the cylinders from long crank times creates an overly rich mixture that the weak spark can ignite.
If you have the requisite FAT, BLUISH-WHITE SPARK, then make sure you have good fuel delivery to the carb. Does your carb have a draiin plug at the bottom of the fuel bowl? If so, open the tank valve fully and using a suitable container to catch the $3.65/gallon gas and open the drain. the fuel should CONTINUOSLY run out. If it dribbles or is intermittent, you have a problem.
Rap the carb with a piece of 2x4. Does the flow improve? If it does, the floats are hanging upon the side of the fuel bowl and restricting the fuel delivery. If that's the case just rap the carb before you try to start. You can pull the carb and look for wear on the hinge pin and pin retainer in the carb that allows sidewise motion of the floats , but a simple tap on the carb to unstick the floats will get you through this summer's chores. My guess is this is your problem.
If the rap does change anything, then look for fuel restrictions in the rest of the fuel elivery system. Some carbs have a screen in the fuel elbow on the carb where the fuel line enters.That could be clogged with debris. I doubt this is your problem based on your description but check anyway. These old machines sometimes have odd failure modes. The tank may have some debris at the outlet that intermittently restricts the flow. Don't ignore the fuel lines. Look for cracks, or loose fittings that can suck air.
If you find nothing there, then it could be you idle circuit is clogged and not supplying enough fuel to start. Once you get the cylinder mixture good enough, it starts and you run at higher rpms on the main and transition jets. You'll have to pull the carb and clean it with carb cleaner to deal with that. This is also a potential cause for your case.
go through these steps systematically eliminating each possibility andyou'll find the cause. Don't throw parts at it until you have determined the root cause of your problem.
Hope this helps you.
