Ellpee and His Magnum, redux By ellpee (Read 478 times)

[ellpee]

Back at our summer place, and though the Magnum is reluctant to start when it's stone cold early in the morning, later in the day it'll start more often than not. I have way too many other things going on to mess with it myself, so am going to drive it to town and let the pros tweak it to perfection, but want to describe its behavior here just for my own education.

When it does start, it needs a little throttle for the first few minutes; the idle is way low and it'll quit otherwise. So I've made it a practice to give it a tad of throttle and block it there. Oddly, though, with the throttle locked at one setting, as it warms up the idle fluctuates up and down. It'll be at 1500 or so, then go up as high as 2500, then drop down below 1000, etc. I could understand one fluctuation when the enricher gets warm enough to shut off the extra gas flow, but not this up and down stuff. Also, I know how to set the idle up for starting, but then once it's fully warmed up it idles much too fast.

So if anybody cares to expound on what's going on, I'd welcome the information. When I take it to the shop, I'd like to be at least a little bit knowledgeable about what MIGHT be the problem, lest they try to pull the wool over my eyes. I've not used them before, so have no idea about their honesty quotient.

[cyborg]

A wavering idle is an indicator of an airleak usually

[ellpee]

UPDATE: Took 'er down to the local shop, explained the symptoms. Spoke with them a few days later; they had tweaked around on the carburetor and checked other things and thought they had everything running smoothly, only to go out the next cool morning and find it wouldn't start. Recommended new carb, which is now on order. If that doesn't solve my problems, might have a Magnum for sale. Last thing I want is to find myself Dead On Road thirty miles from the nearest town.

AND MORE UPDATE: Picked it up with new Taiwan-built carb installed. It has an accelerator pump, which the OEM carb did not, so they advised giving it just one little shot of throttle on cold starts to spritz a little gas into the manifold. Cranked it at the shop, took a bit of serious cranking but it did eventually start. Have tried it several mornings since then, same -- considerable cranking at first, but did always start. While cranking, can hear it wanting to start, which was not always the case before. They did NOT put in high-altitude jets, said this carb doesn't need them, and a plug check after 30 road miles or so looked okay, toasty brown but not black or white. As far as running, seems fine on the road once warmed up, still wimpy on hills but that's mountain living I guess.