Winterize your CCKW
Posted: Wed Oct 14, 2009 3:29 pmThe GMC270 has 2 things to change on the engine for cold weather operation. Cold weather being air temps of 30F (approx) or below.
The accelerator pump has 3 notches for different weather settings. A GM Tech Bulletin allows for the setting to be changed as cold weather approaches. The reason being that cold air is more dense and can hold more gas and sudden acceleration may lean the engine causing it to stumble.
TB G-33 allows mechanics to adjust the accelerator stroke from the normal 'mid setting' to the full stroke 'cold weather' setting. On the accelerator pump piston there are 3 notches. Generally the cotter pin is on the middle notch. But for cold weather service you can remove the pin, raise the pump piston and put the pin on the lowest notch for full pump travel.
You also should turn the exhaust manifold heat riser lever to ON.
Just remember to change them back in the spring.
The top pin is for very hot climates. It allows for the least amount of pump travel.
The accelerator pump has 3 notches for different weather settings. A GM Tech Bulletin allows for the setting to be changed as cold weather approaches. The reason being that cold air is more dense and can hold more gas and sudden acceleration may lean the engine causing it to stumble.
TB G-33 allows mechanics to adjust the accelerator stroke from the normal 'mid setting' to the full stroke 'cold weather' setting. On the accelerator pump piston there are 3 notches. Generally the cotter pin is on the middle notch. But for cold weather service you can remove the pin, raise the pump piston and put the pin on the lowest notch for full pump travel.
You also should turn the exhaust manifold heat riser lever to ON.
Just remember to change them back in the spring.
The top pin is for very hot climates. It allows for the least amount of pump travel.
