Ok experts, I have a 1973 2.0L running Dual Weber 40 IDF's. I'm running at altitude, about 6000 ft, and think I have them jetted pretty close to where they ought to be. last winter I pulled the tranny and rebuilt it. I left about a half tank of premium gas in it during the spring. Now when I'm driving it I get some sort of hesitation at around 3200-3800 RPM in 3rd + 4th gears, most commonly when I'm going uphill. it feels like someone is shaking the car really fast and it doesn't have as much power. I'm thinking either the engine is missing of my clutch is starting to go. I'm hoping maybe the jets in the webers got clogged by old gas and that making them lean out at full throttle, but it is only noticeable when the engine is under a lot of load? Help is appreciated!

Ross

Shine a light down in your gas tank. If you can't see a clean and shiny surface, or you see a lot of dark brown sand, you can bet you have rust.

Nothing short of draining the tank and lines, pulling the tank, having it boiled out or cleaning it yourself with POR15 will do anything to fix it.

I left a half tank of gas in over the winter, did NOT condition the fuel, and in March, I had to pull the tank and treat it with the POR15 3 step process.

I washed out handfuls of rust, but now I can see a nice silvery finish all over the tank and no rust. Not everyone here agrees, but I am a total believer in POR15. I bought the complete 3 step process for about 75 bucks. I sanded and repainted the entire tank and all the parts with primer and rattlecan black satin krylon while I had it out.

Make sure to replace all the lines AFTER you remove them all and blow out the two lines going to the engine with high pressure air maybe with a little WD40 to make sure no rust reaches the carbs. Be prepared to throw away the fuel filter once or twice after all the work, if you have rust. Use only pressure rated teflon fuel lines while you are at it. Millimeter is best and use the right clamps. For 75 bucks and about 10 hours work over a weeks time, you could be golden. I was.

Remove the front hood to remove the tank. BE CAREFUL WHEN YOU DRAIN THE GAS. Many of us have had gas baths on the garage floor. Scariest thing I know in the world. Get a handful of ballbearings about 1/2 inch to roll around in the tank for the first two steps of POR15 treatment. Take the fuel level sensor out. Take off the tank neck. Get new gaskets and make sure you put the bolts back in the tank during treatment. Get a new fuel sock. They are cheap. Make sure you have perfectly flat surfaces where the nipples tighten back into the tank. Note which nipple is where on the tank, but you probably only have one working to the engine since you have carbs. Doubt if there is a return line like on the DJet FI.

Check your fuel filter. If it has that dark brown sand in it, you have rust. Rust is very dark and grainy when mixed with gasoline. The amount of rust may be shocking. It was for me. It got by the strainer sock in the tank, but how I do not know.

Good luck. I had seemingly the same problem. The car really had hesitation issues, then the damn thing would not even start. I had about 2 cupfuls of rust wash out in the cleanout process.

John

I find it interesting that you said that the problem appears when the engine is under a lot of load. This is usually a symptom associated with either the fuel pump or your fuel filter or both. Look for a dirty fuel filter or check the pressure at your FP. I run one filter with the pump, and another in the engine compartment b-4 the tee to the carbs.