Confirming a "starting" issue?

Hello.

I have (what I hope to be) a minor problem with my Massey Ferguson Model 135 Deluxe. At the moment, the choke has more throttle control than the throttle, and I beleive the tractor is in need of a thorough carb cleaning, and perhaps a rebuild. My issue is with "starting". I am having difficulty getting the tractor to start, but when it gets started, it seems to run fine as long as I do not turn off the ignition. If my logic is not too flawed, this woud suggest that the battery is at fault, most likely a bad cell, as opposed to an alternator/generator issue. Does this sound plausible?

Thanks, Ed

If you mean the starter turns over the engine but it does not start easily then I don"t believe your battery is the problem. Its plausible but not probable.You need to systematically check out the ignition system and the fuel system to find the source of your problms. It could be a dirty carb but it could be some ther things, so eliminate some of the common problems and search for the root cause. Don"t jump to a conclusion.

The majority of "failure to start" on engines in reasonable mechanical condition(good compression) are cause by poor ignition system performance. This means you have a weak spark or no spark. You could also have incorrect timing. The second most common cause is lack of correct fuel air ratio in the cylinders.

Pull the center wire out of the distributor cap, hold it near a good ground and try a start. You should have a FAT, BLUISH-WHITE SPARK, the color of lightning. That means a pale bluish white, not yellow, not bright blue, not reddish. If you dion"t have that then there is omething wrong in the primary ignition circuit. Check the point condition( pitted, burned, oily, dirty, etc) Check the point gap. Make sure that when you crank the engine the rotor is turning and the points open and close. Rotate the engine until the points lose then measure the voltage at the battery side of the coil with the ignition switch ON. It should be battery voltage. If it"s not then measure the voltage on both sides of the key switch and on the solenoid because somewhere in that part of the circuit you have a problem.
Look at the insulator on the disributor where the primary wire comes in to make sure it"s not grounded. check to make sure that the plug wire positions match the engine firing order.
The measure the voltage at the distributor side of the coil with the points closed. It should be near zero.

If the ignition checks out OK(FAT, BLUISH-WHITE SPARK) and if you have a manual for your tractor, make sure the throttle linkage is attached to the carburetor correctly. (You said the throttle lever has little control of the engine.) Look at the carb and see if the throttle shaft moves when you pull the throttle lever down. The throtle should generally rotate ~60°-70° of angle from full closed (idle) to full open (WOT). If that"s OK, hold in a suitable container under thecarb, and with the tank valve full open, remove the plug from the bottom of the carb. Fuel should CONTINUOUSLY gush out of the fuel bowl. If the fuel dribbles out or is intermittent, then the fuel delivery is impeded. Work back toward the tank to find the restriction. Look at the screen in the fuel inlet elbow on the carb is your"s has one. It could be clogged. Check the filer in the sediment bowl. Check the fuel vent, usually in the fuel cap to make sure it"s not plugged. if you can"t find a restriction between the carb and the tank then the restriction is in the carb and you"ll have to remove it to see if the fuel bowl is full of crud and not allowing the floats to drop or if the float valve itelf is clogged.

If you have adequate fuel supply to the carb, then look for cracks in the intake maifold, rust holes etc. They will allow air to bypass the carb metering section and cause an overly lean condition. A leaky throttle shaft and a leaking gasket at the carb to intake manifold inyterface can cause the same situation as can a leak at the manifold to cylinder head interface.
you can check this by getting the engine started and spraying starting fluid(VERY CAREFULLY-IT"S FLAMABLE)around the places I mentioned and seeing if the engine speeds up.