VAC Help

[njfarmer]

I recently purchased a 1948 case vac tractor that ran when was parked but was sitting in a barn for 10 years.

The first thing i did was i cleaned out the gas tank, changed the oil and added fresh gas and attempted to start it. All it did was crank and didn't even sound like it was going to fire. I found out that it didn't have any spark so i changed the points, condenser, cap, rotor, plugs and wires. I'm now getting good spark and the the tractor would start but had no power and would stall out like it was starving for fuel. So i rebuilt the carborator and the tractor now starts and runs but it back fires at idle and has no power. Just for the hell of it i decided to to a cylinder contribution test and found that #4 is the only cylinder firing. i have spark at the other cylinders but there not making any power.

Ive never had this problem before and was wondering if any one had an idea of what it could be?

 

[retired farmer]

Your valves could be stuck. Did you do a compression test? Did you check the air intake system to make sure it is not restricted.

 

[casecollectorsc]

Take the valve cover off and make sure the valves are opening and closing. Alcohol or laquer thinner poured over guides while working them will usually loosen them!!

 

[Christopher Mikesell]

In addition to checking the valves, be sure to check the firing order. The firing order is cast into the head: 1-3-4-2. You can work from the firing cylinder in the direction of rotation of the rotor. Also, it is a good idea to reset the timing, since replacing major ignition parts can change it a significant ammount.

 

[old]

You could have a number of problems. Any engine that has sat that long need a good 24-48 hour ATF treatment used on it before you even try to turn the engine over. To do that you fill all the cylinders with ATF and if it has a exhaust that goes up you then pour ATF in the exhaust. Of course have the plugs back in. Then let it sit for 24-48 hours. Doing that will free up sticking ring which is is likely to have an also frees up sticking valves and cleans out a lot of rust that will be in it

 

[C. Amick]

If the valves were stuck, you may have bent some push rods.