misfire at 2500K

[garhett]

Idles Fine, but once it hit's about 2500K or put under heavy load, it starts to misfire terribly. Get's worse as engine warms.

New points and condensers, gaps good too.

[GeorgeT]

Fuel filter; fuel pump are possibilities.

[2ndwind]

Did it misfire before the new points and condenser?

[garhett]

Thanks George, thought it could be in that direction.

Checked the coil today and readings seemed low, bought new coil, but has had no effect.

Did it misfire before the new points and condenser?

Yes it did actually, just never this bad and only noticeable when idling.

I was however not aware of the need for cam lube on the rotor when installing the new points. We did put a sort of high temp grease on there, but does not appear to have worked as the part that contacts the rotor is near completely worn down. Gap does seem fine, but it seems necessary to replace anyways.
Points need to be ordered in so I have to wait a few days to get em, but I'm hoping that it may just be a simple fix as that.

[So Cal Mark]

lube should go on the dist shaft lobes not the rotor. The rotor should have a gap, not be contacting the terminals in the cap

[garhett]

Thank you mark, I understand what your saying. I Was using the wrong terms.

[garhett]

Ok so here's the update, coil tested low so we replaced with new one. Runs again (died while we were listening to it earlier), but runs terrible. Will throw old coil back in there and see what happens.

Car has been running very rich for a while and I have the mixture screw fully seated. I found this great article a while back posted on the forum. ( http://files.meetup.com/533614/Artigue_FIAT_124_MM.pdf )
On page 37 it says that if the car runs too rich, even with the mixture screw fully seated, that it I may need a smaller jet size. I've never even heard someone suggest that on the site here, so I'm a little apprehensive about it. My father advised that we order a carb kit anyways since they're easy enough to do and then we could take at look at the float and such. That will be here early next week along with the points I believe.

Here's what the carb looked like with the top off. The main barrel looks fairly dark on one side. There also seems a be some dirt in the float bowl. Believe fuel filter is new. Was going to get new one today but forgot. I don't have much hope that the problem is the carb, but I'm kind of at a loss here. Again, hopefully it's just the points

[So Cal Mark]

if the car runs with the idle mixture screw seated, you either have the idle too high or fuel is entering through another circuit. Changing jet sizes won't help. Either the float is too high so the main circuit is flowing fuel at idle or the idle jet and mixture screw are worn and allowing fuel to get past. The secondary set screw could be misadjusted also, keeping the secondary throttle plate open. What is the idle speed?

[garhett]

Car normally idles at 1,000 or just under.
If it's not a float adjustment, is it possible to get a hold of a new jet or mixture screw?

[majicwrench]

Like Mark said, it is not the jet. If taper on mix screw looks ok, it is ok. Something is letting in fuel, or the air bleed is plugged. See those two jets in the center of your pic (one says 770) that is where the air gets it the emulsion tubes just beneath jets. Those, and the tube below them,need to be clean. The solenoid to the left of pic needs to come out. The two holes on both sides of the jets, in most cases there are small, brass tubes sitting in them, do you have them?? Dirt in carb is fairly normal for old fiat. Idle of 1000 is high, when too high it can pull fuel from main system.
So, pull idle mix screw, pull soleniod, pull air jets and emulsion tubes. Safety glasses, piss carb cleaner thru everything. Clean jet in end of soleniod with soleniod energized. Put all back together, make sure soleniod clicks with key on when hooking up wire, turn idle mix screw out two turns, see how it goes.
None of this wil fix miss at 2500.

[chrisfiat]

FIRST OF ALL THAT CARB IS FILTHY AND NEEDS TO BE REMOVED AND CLEANED. SECOND IF THE POINT RIDER IS WEARING ON THE DIST LOBES , THE POINT GAP WILL CHANGE. IF THE GAP IS SET THE SAME AS BEFORE THEN THE RIDER IS NOT WORN. THIRD WHAT CONDITION ARE YOUR PLUGS AND WIRES IN, IF THIS CAR HAS BEEN RUNNING RICH (UNLIKLEY DUE TO PLUGGING OF THE JETS, DUE TO ALL THAT DIRT IN THE CARB) THE PLUGS MAY BE FOULED AND NEED CLEANING/REPLACEMENT.....SORRY FOR CAPS, KEY STUCK

[garhett]

Thanks guys. We'll take it apart and clean it up real good, and if everything looks good then see if how she runs.

[majicwrench]

Just FYI, you can get to everything with the carb on the engine. And lots of dirty carbs out there run fine, but you're more than welcome to make it shiny.
Keith