[Spridgets] Issues With Grose Jet Carb Float Needle Seat (Longish)

[Doug Altman]

I've had an intermittant problem last year and this with engine suddenly running poorly - like no power, pedal to the metal, max. 40 mph.  Sometimes it clears up quickly, sometimes not.  Sure, I thought it might be stuck float but problem never lasts long enough to be able to check.  Also, since I put in Mo$$'s Grose jet which they state is a "superior replacement for original style needle & seat," I figured they should be infallible.  So I check dashpot oil, adjust carbs three times, replace stock air filters with K&N style to avoid dirty/stuck carb plungers, set valves twice, new plugs twice, set timing twice, gapped points, new points, condenser, rotor, & cap.  All this over the last year & problem came back during an 80 mile run over the weekend & would not go away this time.  I thought - are the valves burned?  What is going on here?  Carb plungers going up
 & down okay. So as engine runs like crap I pull off plug wire #4.  I have spark between the connector & the plug but engine quits.  Put it back on.  Start engine back up & pull off plug wire #1 - got spark but no change in engine rpm.  Pulled off wire #2 - got spark but no change in engine rpm.  I had spark but was running on only the two rear cylinders!  Put wires back on, spray gas in front carb & engine running improves significantly.  Front carb is not getting gas!  Take cap off float bowl and cannot blow through float valve even though large ball in valve is free.  Tear that "superior" float seat assembly apart and there are two steel ball bearings in there - a big one which is visible and is moved by the float lever, and a smaller ball bearing you can't see because it is hidden on top of the large one and seals against the valve seat
 when pushed by the bigger ball.  That little SOB is stuck solid against the float seat.  Had to knock it out with a nail.  Put stock style float and seat assemblies back in and a drive today showed no problems.  So, beware of Mo$$ P/N 386-390 Grose jets!  (I wish I were a better mechanic!)