How do you know when a Mechanical fuel pump is going or breaking...does it just go or die slowly???

 

ttt

 

Ahh, the good old days of mechanical fuel pumps - 1hr to change, ~$15 to replace & a crankcase full of gas when they went bad!
If it's a simple diaphram pump, when the diaphram begins to fail, you may notice gas stains around the vent hole on the pump and/or the oil level rising in your crankcase. When the diaphram fails, some gas will get pumped to the Carb & some will get pumped into the Oil pan.
Corky

 

thanks im gunna go sniff my oil right now lol

 

We really didn't need to see all the self-incriminating, sordid details. Some things are better left unsaid.

You might not necessarily get fuel in the oil if the pump valves fail on a three-line pump, and all the fuel returns to the tank. If you are suffering fuel starvation, the pukmp is one suspect, the in-tank strainer is another, the fuel filter is yet another, then there's always the float and inlet needle/seat.

 

The diaphram starts leaking fuel out of the vent port and the pump capacity diminishes.

 

yea i have fuel starvation the filters new how do i ajust the float etc.. on a qjet non cc

 

I dunno if its even realtive but you could plug the return line if it is a 3 line pump. Everyone does it with no side effects. I did it not that long ago and notice an improvement in umph. Id probably just get a regular 2 line if I get a new one. Its nice to have the built in reg with a return line but only if I went electric would I worry.

How? well I just cut it near the center of the line where I had slack tied up. [got all new rubber lines] Few extra hose clamps and stuffed a rod of steel in the line to plug it. Them clampped it down well. I guess you can say I still have a bit of fuel psi flex room in the return line.

 

its a 3 plug so im better off buying an new 1 for 15 bucks

 

You have to take the air horn off and bend the ears on the float.

 

Yea, they die slowly. you'll notice that you run out of fuel at higher RPM and it'll stutter. (usually).
My setup to test my fuel pump cost more than a new pump, and only confirmed that I needed a new pump. Best just to buy the pump and be done.

 

ya i just bought one today and put it on....its better but i think i have to ajust my float...do u know how to ajust the float on a non cc qjet

 

Pop the top off the carb, grab your float and bend it up. Spec is something like 11/32" from toe of float to top of float bowl assembly IIRC

Floats don't bend themselves down though, so if this problem just came up, then its not the float level. Unless it started getting porous, so you could replace it - if its floating low.

 

If it is a high level in the bowl, it is more likely a leaking needle inlet valve or a porous/leaking float as Sonix describes, or excessive fuel pressure which is overpopwering the inlte needle valve and flooding the bowl.

 

is there anything else on the carb that i can adjust to fix the problem
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the fuel starving problem

 

Fuel starvation? How have you verified that fuel starvation is the problem?

 

well everything is new on the car besides a tune up on the carb besides i got it from thr junck yard and its bin doin it since then and the car almost stalls out it jerks foward and bogs down badd and when i get off the gas it comes back and hit the gas slightly its fine it only does it at wot..when im messin with the hondas lol
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the carb is clean and everthings on it and the car went to the juckyard cuz of a crash so its prob fine just needs 2 be tuned

 

When it starves for fuel the bowl will not REFILL fast enough to MAINTAIN WOT. It shouldn't cause a bog but will initially run wide open then fall on its face. If this is a mechanical q-jet you've pulled off of another vehicle, what motor did it come off of?

I'd recommend a rebuild, or at least a tear down, to verify everything's good and clean inside, check float settings and that you've got the correct size primaries for your application. You also need to look at the secondaries (size/hanger), proper operation of the secondaries, A/V tension, choke pull-off and linkage, etc.

You've said yourself that it needs a tune up?

 

the qjet came of of a 305 out of a 85 camaro but on another post 1 gave the vin # and its origialy from a 70s 305 i think it needs a tune up cuz the way it acts... where can i get a rebuild kit