Fiat wont start and driving me crazy

[CentFiat]

Hi Fiat Lovers,
I have a 1977 fiat spider that has ran great right before I put it up for the winter. Over the winter I installed new VAS exahust and everything should be great. The car is struggling to start and I believe I have narrowed it down to the fuel supply. I have drained the tank and put new fuel in. I found splits in the rubber section of the fuel line (the larger one) right under the drivers door and i fixed that. I thought the mechanical pump might be broken, so I also replaced that. I still cannot get the car started. If i put gas in the carb, the engine will fire up. I checked the rubber fuel lines right as they come into the engine bay and they are dry. I did remove the fuel pump and made sure the aux shaft was turned right putting the fuel pump lobe in the right spot and then reinstalled the pump. Still nothing.
Is there any tricks I am missing? Does it take a while to prime the line? any advice before i pull my hair out?

Appreciate it all
Rich

[bobplyler]

It can take a while to prime. Also verify that your fuel filter isn't clogged.

[Nut124]

Disconnect the incoming line at the mech pump and suction gently. Fuel should flow into the suction easily. If the check valve works, the fuel should not retreat to the tank.

I would put an electronic pump in the trunk and replace filter and check valve.

[Yadkin]

My '74 has an electric fuel pump from the factory. Why is your '77 a mechanical pump?

[JohnMc]

if you do it safely you can always disconnect the fuel intake line at the carb - and have a catch can and have someone turn over the engine. I have always disconnected the coil to distributor cap so that it does not start.
This way you will see if you are getting fuel to the carb -because if the fuel pump is working you certainly will get fuel coming out.
Could always put a fuel gauge inline to see - but the top method at least tells you if you are getting fuel to the carb.

[CentFiat]

Update: I pulled the mechanical pump again and connected it to the supply line. I used my hand to move the lever of the mech pump and fuel came no problem.

There are some marks on the lever where the aux shaft lobe is obviously hitting it. When I did install the mech pumps, i made sure the aux shaft was in the right position (i.e.: mark at 7 pm).

Is there something I am missing? for instance in how to install the mech pump.

Thanks again
Rich

[JohnMc]

Someone correct me if I am wrong, but I do not believe you can put in the mechanical fuel pump wrong. What you can do is not have a lobe on the auxiliary shaft from changing the timing belt and not having the auxiliary shaft pointing at 1 o'clock at TDC. (I do not have that issue with my little 1438 but did have on my 2.0L).
So as I said before why not just undue the fuel line at the carburetor and turnover the engine to see if you are getting fuel - with the fuel pump and fuel filter in position? Presumably if you have fuel coming out while turning over the engine than you may have a gucked up carb or something else.
And forgive me in advance, but of course the fuel pump has arrows showing input and output.
I am just a shade tree mechanic - well back out to the garage to put my engine and tranny back in on my 1970.
Good luck!

[Nanonevol]

My '74 has an electric fuel pump from the factory. Why is your '77 a mechanical pump?

I think Fiat went from electric to mechanical and back to electric-but probably starting with mechanical.

[JohnMc]

I am pretty sure that there is a small gas filter at the base or bottom of the carb fuel inlet. I had one of these plug up on my old boat - religiously changed the regular gas filter but not the one inside the carb.

[Grewupwithafiat]

Hi CentFiat, did you manage to get it to work? I have the same issue even bought another Mech fuel pump and still not getting fuel to carbs. Like you, filters not clogged, hose coming from Tank is clear I can draw fuel by applying suction, tested the pump by hand like you did and it works. It is also driving me crazy, so it seems that I am missing a step somewhere (as if there is an alignment of the aux shaft that is required so that lever from the mech pump is actuated by cranking the engine), did you finally identify the problem? Thanks!