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Title: Fuel dripping in carb after mechanical fuel pump replacement Post by: Shelley on 16 June, 2023, 08:40:32 PM Hi All,
We unfortunately seem to have run into yet another issue with our newly restored Fulvia S1. :( We took the air box off a couple of weeks ago to fit a replacement "air box support bracket" to our car as it was missing after the restoration and we had read on this forum how the lack of support could put a strain on the rubber carb to head coupler (even this is complex as we discovered there are two different lengths of this bracket so we had to cut down the one we had bought to fit!) After fitting the bracket, we reassembled and started the engine to test all was well only to notice that petrol was slowly dripping from the original Fispa mechanical fuel pump! Therefore, given this is 54 years old and stood dry for 40 of these we thought best to replace this so we ordered a new one from Omicron. We fitted this today and this is not leaking and seems OK but now we have another new problem! The car starts OK but after running for maybe 1 minute we can see a lot of petrol dripping inside both inlets of the rear carb to the point that it pools and starts dripping out onto the drip tray, obviously the engine starts to misfire with this much fuel sloshing about. The front carb seems completely happy with no drips at all. We have a copy of the Omicron "Setting Fulvia Solex Carburettors" booklet which states that drips are likely to be cause by (in descending order of likelihood): 1). Incorrect Carb Float Level 2). Dirt preventing the needles closing 3). Excessive Fuel Pressure The car was running well before we changed the pump so (1) seems unlikely? unless the new pump has raised the fuel pressure compared to the tired original one (3) could this mean that the higher pressure might raise the fuel level if the float level (1) wasn't quite right?. Given we have disturbed the pump (2) seems the most likely scenario even though the fuel hoses and filter are new about 300 miles ago and we were careful to keep things clean when we were changing the pump (we have noted that our fuel filter is fitted before the pump but in the Lancia repair shop manual PDF it seems to suggest on some models the filter is after the pump? does anyone know what is normal?) Therefore it would seem the next step would maybe be to check if there was dirt in stopping the needle closing or / and the float level is wrong? our main problem is that information (in particular pictures) on how to do this is very sparse, I think we are spoiled that for most things that go wrong now there is usually a YouTube video explaining exactly how to disassemble / fix / reassemble but not so it seems for the Solex C35 carb! We have read quite a few posts from Tim "LanciaLulu" on the forum stating the fuel level should be 19mm from the top of the float bowl and that a cable tie can be used to check by removing a jet this but without pictures its quite hard to visualise how to do this for someone new to Fulvias and we are a bit nervous of just starting to undo screws on the carb without knowing what is "safe" to dismantle and what isn't. Given all of the issues we are having we have booked to take the car to Omicron in a couple of months for a proper health check but in the mean time we just need to correct this issue sufficiently for it to be able to get there (as its about 100 miles away!). If anyone has any photos (the more idiot proof the better) that would help us understand how to dismantle the carb to check the needle and float level that they could share we would really appreciated it, given the car was running OK before we touched the pump hopefully just cleaning / freeing something will be enough to get things going again! Kind Regards, Shelley Title: Re: Fuel dripping in carb after mechanical fuel pump replacement Post by: dhla40 on 17 June, 2023, 06:46:27 AM Do the carbs have a fuel return line? If not get a filter king regulator and set to 3psi. The pump should have an internal filter gauze, if you have a filter before the pump make sure it is not too restrictive.
Sean Title: Re: Fuel dripping in carb after mechanical fuel pump replacement Post by: lancialulu on 18 June, 2023, 07:35:22 AM sent you a PM
Title: Re: Fuel dripping in carb after mechanical fuel pump replacement Post by: Shelley on 25 June, 2023, 08:05:25 PM We have now fitted a Malpassi Filter King set to 3psi between the fuel pump and the carbs and the pooling of fuel in the carbs has ceased.
The Filter King fitted perfectly onto a bracket behind the fan so we feel that there was probably a Fispa regulator there at one stage. Thank you for your replies :) |