About the '87 Mazda B2600 that hesitates on acceleration that I called about... I've got it fixed. This thing sat around for a year or better without running. The mechanical advance linkage, where the pins on the weights fit into the linkage arm, needed cleaned up. That helped some, but the real problem was binding and stiffness between the distributor base plate and the plate moved by the vacuum advance. It was moving some, but not through it's whole range, and not near as freely as it ought to. [ed.note: there are normally a set of small ball bearings that the plate rotates on and they get rusted and gummed up - this is most likely where the problem was]

I did take it to an independent shop with a list of things for them to check for me. They didn't really answer any of my questions, and told me that "some of the vacuum hoses are routed wrong, and I needed a new ($550 installed) carb to replace the new one in the truck, because you can see gas puddling on the throttle plate when its idling". I told them I'd been staring down that carb for a week, and hadn't seen a puddle yet. I also asked how they knew the carb wasn't right if the hoses are routed wrong, since this feedback carb depends on vacuum powered servos,sensors, and solenoids. Response - "we just know it is".

That experience was enough to get me thinking about it all some more, and I just wasn't confident that the advance mechanisms were doing what they should, and I wanted to verify that the air gap for the reluctor/pickup coil was right anyway. This distributor is very accessible, so I just pulled it and went to work.

Thanks for your help! If you want to edit this and stick it in your user anecdotes, feel free. I think that with more and more vehicles getting into the 100,000 mi. + category without much service, this sort of thing will be happening more often.

Tom Denniston

Message me at BobHewitt@Misterfixit.com

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