Funny misfire

[Lawrie]

We had just done a big trip in the 33 without any dramas,in hot and rainy days.
On sunday we went for a 300 KM trip and on the way back it gets this funny miss,it would pull strong, run at 50-60 mph but lift of the gas and there it was,no mater what speed.got home OK.
spent the last couple days sorting it out.
changed plugs (new,and old ones were OK)
fitted new coil and condenser (no change)
cleaned carb,no change,fitted new carb,no change.
removed and checked plug leads and terminal plates. no change
removed distributor,stripped and checked points,firing points a little dirty,
BUT the little plate with the slots in on the distributor shaft that controls the advance weights(11a-12181) was real loose and probably 10 deg radial play,
fitted another shaft with the plate tight and hey presto miss gone.
I think what was going on was when I lifted off the gas the high vacum lifted up the vacum brake cylinder and let the whole lot flail around,the timing would not know where it was.
So now I,m on the lookout for a NOS 11a shaft or a good used one.(for the helmet distributor.)
Lawrie

[larrys40]

Sponsored Links (Register now to hide all advertisements)

It's typical they aren't real tight and are on the loose side. I don't think that was your problem.. I think when you put it back together you probably changed,regapped, reset your points and if you have a stroboscope dialed it back in and that's what made the difference. I've rebuilt many and strobed on my heyer units and usually it's the points, point float ( if poor quality and out of spec) that cause many issues.
Just my educated guess.
Larry