Here is a problem for all you kindly bus mechanics:
I put a rebuilt stock 1600 DP in my 70. New accessories; carb, pump, dizzy, plugs, wires, everything.It idles and sounds fine but when I drive it 2 blocks it stalls and won't start till it sits a few minutes. Increasingly dead pedal till it dies all together. There is fuel all the way up and it runs just the same with any combination of the old parts.
My case is from a type 3. Is it possible that the fuel pump push rod is different, (shorter) than needed and hence, low pressure? ANY suggesstions at this point would be a God send.
Thanks
Ray,
This bus only sat for a month while the engine was out. I recently put 800 trouble free miles on it (till the old engine case cracked).
The old carb worked fine on the old engine but, like the new carb, no change on the new engine.
Do I have to pull the engine AGAIN to access the fuel tank screen?
Al
Check your pump rod length in relation to the pump. There are two lengths available, turn motor over by hand till the pump rod is at its highest level, set pump down over rod and verify the rod is pushing the lever all the way up. You could also have a new "bad" pump.
If your bus still has the "sock" screen filter in the tank, remove it and avoid installing another. Best to install a fuel filter under the bus between the tank and where the fuel line enters the engine compartment. This eliminates the chance of building up crud in the tank and if the filter leaks or breaks no fuel dumps on the engine.
Also check the fuel lines. Laugh all you want but in the three weeks I had a motor out a bug build a nice little nest in the fuel line, massively restricking flow. It never dislodged, just reduced flow to a trickle.
Check the float level, and that the float valve is working.
Hi again,
No, I didn't adjust the float level in the new carb for two reasons:
-I'm told cracking the seal (paint) would void the warranty and, the old carb was set but the engine exhibits the same problem.
The rod length is the correct 107+mm and pushes the pump lever same as the other working pump.
How about my replacement SDVA dizzy? Could there be a cam/rod relationship difference? Tonight I'm going to see how far gas squirts while cranking. I don't have a fuel pressure guage and it will never make it to a shop. I'l also replace the hose from the (under side) filter to the metal line. That was the side pinche off with the vise grip during disassembly.
Wow, this is frustrating.
Thanks for the feedback.
A little logic for you. The carb has no care really what the pressure is. It does not need to be much. Enough to keep the flow bowl filled is all it needs. Now it could be slow...but what you need to measure is volume. The crap about not cracking the seal is crap....from the guys you bought this from. Never install a carb without personnally checking the float.
Bear this in mind: If its a problem with the pump keeping up...why would you need to let it sit for a few minutes to start it? It would simply be a matter of cranking the engine while the car is not moving...until the bowl fills. Thats like 30 seconds at the most. Unless.....you are actually flooding the carb due to a float valve not sealing, or fuel oeverflowing from the bowl vents. That would be a float height problem. There is also the possibility that you are sucking crap into the sock filter...strangling the fuel flow...and clearing the sediment when the line empties back into the tank...allowing the fuel to flow again. That is 100% common. Unless you KNOW that you just recently cleaned the tank and sock filter...there is 100% chance this is the problem. Ray
Ray and others;
I replaced the fuel line, (it was fine), the filter sits 6" shy of the metal line underneath, the float is set to speck and there is no change. I can let it idle or rev it up until I drive it one block.
About the "sock": My bus tank has a nut out the bottom with a fuel line only. What does this sock look like? It comes out of the tank with that threaded plug? I can not find a description of this item anywhere.
Could this be a failing ignition coil under a load?
I'm ready to have it towed away!
Soaked with gas in Portland
Ok...thanks, you answered the float questions. The sock filter is attached to the end of the fuel pipe inside the tank. If you remove the nut, the pipe will come out with the sock attached. Ray
Take a new line from the filter / pump inlet, stick it in a little Jerry Can of gas, and rev it high. IF it works for about 3 mins, your tank is plugged, if it doesn't, you're into carb or pump problems ...
Easy Breezy ...... you also won't get soaked with gas this way ... unless you spill your Jerry can ....
My "fuel" problem turned out to be the coil !!
Apparently, they can go bad when they warm under a load. I guess they expand and contract and short out. Just a few moments of sitting is sufficient cooling to allow a start.
I did replace the tank sock filter but it only showed a 1/2" of slight crud after 33 years.
I learned something and owe my neighbor a beer or three.
Thanks for the feedback on this great forum.
send.
