I've darn near replaced everything- literally everything in my 74 mav (250 I6- mostly stock) other than the engine itself trying to fix a problem. The issue I see now is that the car idled HORRIBLY after a head gasket replacement. Some fast idle adjusting fixed this, it purs beautifully now. It also hesitated (even in park or neutral) when stomping on the gas. When I say hesitate, I mean it almost dies. We narrowed it down to the carb (which I recently rebuilt) and noticed that the accelerator pump does not move down in synch with the linkage. It lags quite a bit. I tested this by pulling the throttle near-wide open with my hand and at the same time I pushed down on the accelerator pump- worked perfect. So I took the carb apart, checked everything- seems fine except it gives resistance when it tries to "pump." It isn't stuck completely, just really hesitant. Almost seems like oil would fix the problem but as soon as the gas touches it, the oil would be gone. Or maybe if the pump spring had more tension? What should I do? Could I have installed the spring backwards? GRRRR I don't know what to do!
there is probly some restriction in the fuel pump circut. id sugest takeing the carb apart again. and clean the fuel pump circut. with carb cleaner and compressed air.
Okay, picked up some berrymans B12 - disassembled the carb and accelerator pump assembly, cleaned everything out, sprayed into all the ports, etc. let the pump, diaphram and spring bathe in a chem bath. Did not work. I even noticed that when putting the accelerator pump and diaphram back on that it was noticeably giving too much resistance while "pumping" even though it wasn't "under load" so-to-speak. I checked the vacuum advance just to make sure that wasn't bad- it's fine. Once again, when applying heavy throttle at the carb by hand, the engine hesitates big time. If I force the accelerator pump down (in synch with the linkage) there is no hesitation, everything is perfect. I'm starting to think just fabricating a secondary arm to go above the accelerator pump that forces it down with the linkage... That, or getting a pump spring that has a crapload more tension.... It's driving me insane. If it's something like an oversized diaphram causing the problem then I'm screwed because there are no other carb kits to buy (don't think this is the case since the kit was designed for my year/model.)
-if you get the Mav back together and running good we got a cruise and show on Memorial weekend. http://mmb.maverick.to/showthread.php?t=52563&highlight=colby
Have you tried adjusting the accelerator pump linkage???It sounds like the linkage isnt actuating the pump properly(or at all)Also exposing the pump piston to some solvents will cause it to swell up or shrink and dry out.If its swollen up,that would explain the heavy resistance.check the linkage out first...be certain nothing is binding up...
The linkage itself does not actuate the pump. There is an internal spring that actuates the pump. The linkage itself keeps the pump in a upright "primed" position. Once the throttle opens, the linkage moves down, allowing the internal spring to extend / actuating the accelerator pump. This is what I meant by fabricating an arm above the linkage to actuate the pump.
It's the stock Carter RBS carb. I'm thinking it has to be the spring... I'll try to get a video up on youtube and provide the link to help explain things...
Okay, got a video up and going. At first I was being gentle, then I hit it wide open to simulate stomping on the gas.... You'll notice a pin on the plunger that will keep the pump itself from falling too low into the fuel bowl- that's what you should keep you eye on while watching the linkage....
you have some parts missing...The spring should be between the actuator rod and the piston...not under the piston in the bore.There should be a few shims(washers) that go over the top of the spring along with a spring seat/keeper to keep it on the shaft.
.... Awesome... Rebuild kit's that I've seen don't have any additional parts and unfortunately mavericks are pretty rare where I live. If anyone knows where to find said missing parts, I'd be grateful to hear about it. In the meantime I've found..... a very oversized high tension spring to replace the last one..... I know it's a horrible thing to do, but I really don't have much of a choice at this time... heh.
Pay no attention to the above statement...I was confused (ALOT)I am such a dummy sometimes...Sorry...You have it assembled correctly...The only problem I can come up with is that the piston is incorrect for the application or it has swollen and is binding in the bore.Get a new piston and the problem will most likely go away.
Heh, no worries. Makes me happy actually that I'm not missing parts. I'll look around for a new piston, thanks for the info.
Sorry about the screwup,I misinterpreted the parts breakdown pic I was referring to.I think a new piston will solve your problem.Good luck!!!
