Float level 1.3 Fulvia

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lancia7550
Posts: 74
Joined: 10 Nov 2012, 22:26

Float level 1.3 Fulvia

Unread post by lancia7550 »

I have searched the forum and can not find info on Fulvia Solex carb float levels and how to measure them. Both my floats' arms look straight, which I believe is correct, but one carb' s level appears lower than the other. Any advice would be appreciated.
bmarler
Posts: 110
Joined: 22 Dec 2008, 17:33

Re: Float level 1.3 Fulvia

Unread post by bmarler »

if the carbs are off the car you can check them with a small fixture you can make. but there are things to complicate matters, like if you have the correct thickness washer for the needle valve that's installed. so, when i check it, if the carbs are off the car i'll put them in a bench vice and fill them through the hose, using the needle valve to set the level. then pull the top off the carb, including the gasket, and use a caliper to extend down till it just touches the fuel.
actually, i do it that way when they're on the car too. the target is 20mm if i remember correctly. you can carefully bend the float arms to achieve this.
i use some small pliers to do this work, i avoid touching the floats with bare hands as you can damage them.
marnix
Posts: 53
Joined: 15 Dec 2015, 21:29

Re: Float level 1.3 Fulvia

Unread post by marnix »

The Solex C.35 for the 1,3 Fulvia have gone trough quite some evolution, so, in order to give you the correct data, we first need to establish:
- version of the carbs (can be found stamped in on/over the PHH roundel); - on the small roundel next to the PHH roundel, the number that is there in small (29 or 31). - Just to be rather safe that we have the correct carbs for the engine, engine type 302 or 303 - which mean 1,3 or 1,3S. - series of the car (S1,, S2/3); if available, approximate manufacturing data of the car, and country it originally was sold to.

When we know what we are talking about, I can supply all data. I have the information for all the carburetors that were used on the Fulvia.

The float level can be measured on car or off the car.

Marnix
lancia7550
Posts: 74
Joined: 10 Nov 2012, 22:26

Re: Float level 1.3 Fulvia

Unread post by lancia7550 »

Thanks - It is for S1 1.3 Rallye S, 818.303 engine.
PHH13 carbs, currently on car.
marnix
Posts: 53
Joined: 15 Dec 2015, 21:29

Re: Float level 1.3 Fulvia

Unread post by marnix »

Is that a car with an oil bath air filter? If not, it may be that they replaced the standard PHH 10 (S1 1,3S) with these PHH 13 as replacement, but then it may be necessary to check on the jet sizes: the PHH 13 is different from the standard PHH 10 version by having different jet sizes: PHH 10 air: 180, fuel 120; PHH 13: air 190, fuel 110 (the PHH 13 is made to give a bit less fuel and a bit more air, as the oil bath filter adds some "fuel" in the form of oil vapor). Pilot (idle) jet for both 47. Checking the air jet is easy (under the small jet cover). For the fuel jets, the carbs need to be taken from the car and opened at the bottom.

The sizes in relation to the float level are as follows (both for PHH 10 and PHH 13): needle valve 1.1, needle valve crush washer 1mm, float level 20mm + / - 1mm, fuel pressure 0.25 bar.

To measure float level: run engine, switch off, remove top cover of the carburetor. Remove seal (taking care to remove the small brass "economat" tubes first that that normally prevents the seal from being removed as their tops stick over the openings in the seal). With a slide caliper that has this kind of pin to measure dept, measure the level of the fuel from the top of the center "tower" (were the jets are screwed in at the top) to the fuel (slowly lower the pin till it just touches the fuel - the fuel surface will suddenly kind of "stick" to that pin when it reaches the fuel level). Best measure at different positions along the center tower. The 20mm is WITHOUT the seal thickness.

In theory, with a good new float, the right crush washer, the correct needle valve, AND the correct thickness of the seal it should be right. It almost never is correct just like that however (with a lot of struggling I sometimes manage to get it right like that, but usually not). To adjust, very slightly bend the arms of the float at the position where the arms connect to the central part that operates on the needle valve. Bend only a tiny bit, the slightest bending gives an "amplified" result (big difference in float level). Make sure the bending of the two arms is exactly the same.

Adjusting "off-car" following Lancia instructions is a rather complicated and also clumsy affair, that requires a long description of the tools and procedures needed. It can be done the same way as on car with the slide caliper, but then you need some kind of external fuel tank and pump with the correct fuel pressure to fill them.

Good luck. If not clear, ask away.

Mx
lancia7550
Posts: 74
Joined: 10 Nov 2012, 22:26

Re: Float level 1.3 Fulvia

Unread post by lancia7550 »

Thank you, that is great information. Yes, the car had a oil bath filter since new, but I have removed it and fitted a standard air filter. When I checked the jets I noticed that there should be different jets for the different air filters, but the ones fitted were the same as for the standard air filter, so someone must have messed with it over the years. Good to know though that the jetting is correct for the filter now.
marnix
Posts: 53
Joined: 15 Dec 2015, 21:29

Re: Float level 1.3 Fulvia

Unread post by marnix »

maybe four small additions (some that I thought would be obvious):

- to run the measurement, car must be on a perfectly horizontal floor, and the car itself as best as possible horizontal (tires, suspension, etc).
- while measuring the level with the slide caliper, the float must remain IN of course; it makes lowering the pin of the slide caliper a bit awkward to get it down next to the float in the fuel, but it can be done.
- the carbs are slightly tilted towards the engine; but the design is that the central "tower" is always more or less in the center of the fuel pool (for all kinds of attitudes of the car), so when measuring at the location of the central tower you got more or less the middle of the fuel "pool". But that is why it is still best to try to measure at different locations along the central tower, and if necessary, average out a little bit yourself.
- after checking/setting the float level, do the following test: remove the air filter element, so that one has a clear view through the velocity stacks towards the aux venturies (a good small light may be needed). Run the engine, and look at those venturies; activate throttle a few times, and observe fuel spray coming out of the venturies. Now the important part: when returning to idle, fuel should stop coming out of the aux venturies. Sometimes they still drip or keep wet (especially on #2 and/or #4). If that is the case, lower the float level a little bit, if necessary to the lowest limit of 21mm.
lancia7550
Posts: 74
Joined: 10 Nov 2012, 22:26

Re: Float level 1.3 Fulvia

Unread post by lancia7550 »

The one carb's float level was sitting at 19mm and the other at 21mm, hence why they appeared to be quite different to the eye. Not too bad though and with a bit of effort got them both to exactly 20mm.

Just another question after checking the jets over again, what is the third jet at the bottom of the carb between the main fuel jets? I can really make out the markings on those.
marnix
Posts: 53
Joined: 15 Dec 2015, 21:29

Re: Float level 1.3 Fulvia

Unread post by marnix »

The third jet is the jet for the "choke" (or "starter") fuel supply. It is normally a 90 jet (marked ST90, for "STarter 90"). All Solex twin choke carbs for the Fulvia have 90 for that jet. It is less important.

In the end, both carbs were just within limits, be it is better to have them the same and more or less at the correct level.

For good running at idle it is imperative to have the balancing done, for starters between the two blocks (which is essential), but also internally for each block between the two sides of each block.
lancia7550
Posts: 74
Joined: 10 Nov 2012, 22:26

Re: Float level 1.3 Fulvia

Unread post by lancia7550 »

My car is running very well, but I have noticed that the float level on the front carb appear to drop, causing a slight hesitation when coming back on throttle. Any pointers on what might be the problem?
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