International Lancia Forums

sorry for the length of this post, but i wanted to give as much info as possible.
i'm having a little trouble with my 1st series 1.3 fulvia sport engine. until very recently its been a pretty good runner, not perfect but respectable. here is a little background, 35phh solex carbs, point ignition, all factory as far as i know. i recently pulled the carbs to reseal all of the intake connections to cure a deceleration backfire problem i've been having. while the carbs were off i noticed two of the accelerator nozzles were not squirting fuel as they should. cleaned these out with compressed air, cleaned up the carbs and re-assembled. now it's all resealed, new strut to hold up the carbs and new air filter. cured the backfire problem totally, i was really pleased with the result. thanks to shaun for the idea.
now the problem begins, while fiddling with the carb settings the engine began to misfire. eventually got so bad it wouldn't start at all. pulled the plugs and they were sooted badly. ngk bpr7es. so i put in a new set of iridium bpr7eix and a new set of 8mm wires. during this i see that the spark seems to be pretty weak at the plugs. changed the points and cap, still weak. started the motor anyway and it ran perfect. smooth through the rpm range and lots of power. the exhaust smells rich, (but it always did) a couple of miles down the road and it starts misfiring again. get it back to the garage and pull the plugs and they are all sooted up again. what am i missing here? is the weak spark the root of my problem? should i be able to see it clearly in the daylight? also wondering about the gap setting on the new plugs, is anyone else running these, an if so at what gap? ngk recommends .06" but i know this is wider then the setting for the bpr7es. also thinking about the float setting. anybody have a good way to check this? i'm happy to pull the tops off the carbs and measure down to the fuel level if anyone knows the proper distance it should be.
thanks for any insight.
brian

i may have some resolution here, i measure the primary resistance of my coil at 4.4 ohm. the previous owner had a ballst resistor installed on this coil. i will remove it and check for better spark. anybody have a part number for a suitable condenser for series one distributor?
brian

Dont like to say it but sounds maybe over rich and something you have done to the carbs on rebuild. I have this on an HF if I use champion plugs and the car has stood I always lose No1 cylinder and it will not come back. I changed to NGK's and touch wood I havent had that problem again. But a new problem is on the list to solve and sounds similar. I replaced my open trumpets (ran with piper cross socks and no problems) with the standard air box and filter for a quieter car for a long distance run but now it has a misfire/hestancy in the mid range. very peculiar.

Tim

thanks tim,
it seems my problem was rooted with the ballast resistor on the coil. i removed it and like magic the car runs better than ever. (with yet another set of new plugs) funny the problem didn't arise until i changed the factory airbox for the custom one i made. maybe more airflow and clean fuel passages helped to make the ignition problem show up. i still would like to find a good way to doublecheck the fuel level in the solex carbs though.
brian

Hi Brian,

I'm not sure I follow how more airflow -- from the new airbox -- would lead to the problem you had. But I'm pleased that the ballast resistor seems to have been the culprit.

There have been previous threads on this board about checking the float level (here's one: float level setting.

This seems to involve acquisition or construction of a special tool for the Solexes.

I've not done this; the only operation on the floats I've done is to take them out and check them for leaks on occasion (a legacy of having owned British cars with SU carburettors).

Regards

Needle valves can give problems if they don't operate smoothly. The 302 engine has a different type of needle valve from the 303. See the manual. Andrea

Andrea,

Is there a mark right on the needle valve which distinguishes the different types or is it a matter of measuring the spring strength or hole size?

Also when the American Lancia Club was still sending out paper newsletters (a long time ago) there was an article on reducing the amount of gas released by the accelerator pumps. This would result in smoother take offs by avoiding drowning the plugs in gas. I don't think this is related to sooted plugs but something else to check when having the carbs in your hands.

Also a comment was made about how could a change in airbox design could result in fuel delivery changes. I believe that's entirely possible because my blurry mind remembers different jets being specified if the air filter had oil or not.

Ralph

Hi Ralph, I am quoting from memory and I might be wrong, but I think that the 302 carbs take needle valves with 1.1 stamped on their flat, while the 303 carbs have 1.3 stamped on. I would have to check this in my stock of spares. Regrettably I have no experience in cleaning air boxes: all my Fulvias run with standard ones. Best regards, Andrea

i believe that ralph is talking about oil bath airboxes. whether or not the higher airflow contributed to the problem i may never know but i'm happy to be running properly now! i will check the needle valve stamping next time i have the top off the carbs to doublecheck the stampings.
on to the next problem i guess...no dash lights hmmm
brian

thanks shaun,
i remember reading that post but there was never any sharing of the dimensions for the tool. anyone have this?
by the way you suggestion of re-sealing the intake side of the motor worked very well for eliminating the backfire upon deceleration. now i have to make the old popping sound myself