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Discussion Starter · #1 ·
Is there a way to "prime" a mechanical fuel pump? I haven't driven my car all summer and trying to get her running for the fall. It will fire on starting fluid. It appears no fuel is getting to the carbs. I pulled the fuel line to the carbs and tried to start the car expecting to see gas squirting out but no. I even pulled the filter bowl and added gas to it. There was gas in the bowl when I first took it off. About 3/4" worth. I know it always takes some time for the gas to get from the tank when I normally get her running in the spring, but this seems to be more time than usual.

Is there another way to test the pump to see if it's working? I am assuming it is the original one on my 1970 GTV(Canadian).

Thx
HB

P.S. It is a mechanical pump
 

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In the past, I have carefully pressurized the fuel tank with my air hose from the compressor regulated to about 10psi. Disconnect the hose at the pump and put it in an empty beer bottle. Push the fuel through and then reconnect hose to pump. If that doesn't work, try pressurizing while cranking. If it still won't pump, you might need to service the pump.
 

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Discussion Starter · #3 ·
I pulled the pump and took it apart. Everything inside looked fine. No rips in the diaphragm. Forgot to note orientation of all the insides. In the attached pic I am assuming C(o ring) goes on E and then E(with o ring on it) goes into B. And when the pump goes back on block, does the pushrod need to be extended or pushed in. Thanks
 

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But Mad North-Northwest
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Just don't try to suck the fuel to the front with a shop vac. Buddy of mine tried that once. Worked great until the fuel vapor hit the motor. Shop vac made a phoot noise and started shooting a continuous stream of flames out its exhaust.

He was in the driveway so didn't burn the house down.
 

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Pretty common issue if i have it lay over without starting .. like 3 weeks is the threshold.. I have a clear Cavis crossover pipe (stock in '72) between the carbs so there is no mystery what is happening if I don't get a start and no bubble in that line. I pull the feed line to the crossover line and put about a 1/2 pint of gas in the line with an old 3M quart can that has the plastic squirt snout on it .. It fills the fuel line back to the gas tank and more cranking will get you started ... When my "helper" says .. "Houston , we have a bubble".. ignition is just an eyelash away.The line back to the tank dries out and needs to be primed and the poor mechanical pump is tired and not going to get it done by itself... It's easier than it sounds with pinch claps at the connection. Works for me.
 

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Discussion Starter · #8 ·
Thanks guys, I had a feeling that the pump was not original. Once I pulled it I could see the words "TESTED" stamped on the side. And the guts of it looked real clean. I do have to laugh because I jammed a piece of aquarium air tubing into the main fuel line from the tank and figured I could suck until I see gas enter the clear tubing. Well that was the plan. Ended up with a mouthful of gas. I mean they do that in the movies all the time. LOL. Oddly sweet.

But at least I know there is fuel in the line.

So while the pump was off the block, I had my son crank the engine while my finger was on the pushrod. It moved in and out very slowly in very short strokes(keep the comments clean, lol). I don't know if that movement is normal for the pushrod for a mechanical pump. Maybe that's an issue. Hopefully not.

Took the complete fispa glass bowl housing unit to check it out. No plugged lines there. Cleaned it up and but it back with the bowl bone dry.

Figured after installing everything back in place and cranking the engine, I would see gas in the bowl. No gas. Still dry.

I'll keeping digging and hopefully figure out what's wrong. I also have a clear line between the carbs and do look for the infamous "bubble" too.

BTW, the PO did put what looks like a lawn mover fuel filter, inline about six inches from tank. I did pull it and blow it out and gas did freely pass through it. Maybe I need to put a new one in place or remove it completely. Maybe it's restricting the flow enough to muck up the suction of the pump.

P.S. Worse case I'll buy a new pump from the UK. Looks like I have an FL004 pump.
 

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You could buy a cheap hand priming bulb (as used on some motorbikes/outboards) and put it in the line before the mechanical pump. Squeeze and release, say 10 times, it should draw fuel from the tank, through the mechanical pump, through the filter regulator and fill the carbs until the float shuts off the flow - bulb will go "hard". Once primed, start the car. If it continues to run, then the pump is good, if not, then there's a problem. Leaving the primer bulb in place for the long term might not be a good idea - over the years, the rubber will degrade and leak. Mine has such a bulb in place at the moment - saves me beating the hell out of the starter motor if the car has been standing for a couple of weeks or more. Laser Fuel Transfer Tool 8mm
 

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Just don't try to suck the fuel to the front with a shop vac. Buddy of mine tried that once. Worked great until the fuel vapor hit the motor. Shop vac made a phoot noise and started shooting a continuous stream of flames out its exhaust.

He was in the driveway so didn't burn the house down.
Or my friend who used a shop vac to clean out spilt fuel in his Formula Vee. Nearly lost that, plus his very nice 911 SC, a couple of other cars, and the garage. We still get mileage on that story many years later...
 

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The PO on my 1750 added an electric fuel pump with it's own toggle switch. I hit it before starting, wait for the "tic-tic-tic" to slow down and she rolls right over. Then I switch it back off. Might be a worthwhile gizmo to add so as to avoid this in the future. The switch lives out of sight under the dash so no odd, extra switch is in view.
 

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Discussion Starter · #14 ·
You could buy a cheap hand priming bulb (as used on some motorbikes/outboards) and put it in the line before the mechanical pump. Squeeze and release, say 10 times, it should draw fuel from the tank, through the mechanical pump, through the filter regulator and fill the carbs until the float shuts off the flow - bulb will go "hard". Once primed, start the car. If it continues to run, then the pump is good, if not, then there's a problem. Leaving the primer bulb in place for the long term might not be a good idea - over the years, the rubber will degrade and leak. Mine has such a bulb in place at the moment - saves me beating the hell out of the starter motor if the car has been standing for a couple of weeks or more. Laser Fuel Transfer Tool 8mm
Malcolm, thanks for the tip. Could grasp the concept until I clicked on the link for the Laser tool pump. Hopefully my local parts store will have something similar.
 

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Discussion Starter · #15 ·
Bought a fuel transfer bulb from a local big box store and it couldn't siphon spit. So I took a long piece of clear tubing and mated it with the fuel line from fispa filter to carb line. Sucked on the line until I heard gas gurgling in the pump, the filter, and then into the clear line. Reconnected the lines and tried to start the car. Zip. Looked everything over and then noticed gas in the clear Cavis line between the carbs! Went back and started it and she fired right up. Been starting up fine after sitting for a few hours, so I think it's fixed. Last test will be starting in the morning. Not sure why she was giving me so much trouble getting fuel up to the carbs. Thanks for the help.
 

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In the spirit of this thread, I would like to put a short length of clear fuel line between the carbs to see how the fuel supply/level is in various situations/times. Any advice on what to use/not use? I think the OE was Cavis clear green?
 

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I drove my GTV Saturday morning and this morning 48 hours after driving there was no fuel in the line from the front carb to the fuel filter regulator 12" away. So I temporarily put in a clear hose for test purposes. (A short piece of the clear hose gets pretty hard submerged in gas for a week.) In the summer my GTV usually sits for a week sometimes 2 between drives. My starting procedure after 1-2 weeks is to hold full throttle and pull choke fully, pull fast idle lever about 1/2", crank the engine for 10 seconds, release the throttle and it fires and runs, push in coke gradually and fully over the next few seconds then play with hand throttle to get 1500, blip throttle a few times over the next 30 seconds and I am ready to drive off gently.
If I drove the car the day before I use the same procedure except I will release full throttle after a couple of seconds of cranking. The less time between drives allows quicker starts with much less in the way of special techniques.
The first start in the spring is similar to the starting after weeks of not driving except that the plugs will be loose because of adding winter storage oil in spark plug holes. So initially I crank the engine with no plugs until I read oil pressure on the gauge and idiot light. Then plugs go in and it starts. A couple of springs ago I had a problem like howieb4 and it wouldn't start, no gas movement. I took the fuel pump apart to find nothing visibly wrong. Put it back on and it finally started with more cranking. I guess I didn't crank it enough with no plugs or with full throttle the first time. I think the 2 one way valves in the fuel pump allow gas to seep back towards the tank over time. They work well enough when the engine is running. but not good enough for extended downtime.
 

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I drove my GTV Saturday morning and this morning 48 hours after driving there was no fuel in the line from the front carb to the fuel filter regulator 12" away. So I temporarily put in a clear hose for test purposes. (A short piece of the clear hose gets pretty hard submerged in gas for a week.) In the summer my GTV usually sits for a week sometimes 2 between drives. My starting procedure after 1-2 weeks is to hold full throttle and pull choke fully, pull fast idle lever about 1/2", crank the engine for 10 seconds, release the throttle and it fires and runs, push in coke gradually and fully over the next few seconds then play with hand throttle to get 1500, blip throttle a few times over the next 30 seconds and I am ready to drive off gently.
If I drove the car the day before I use the same procedure except I will release full throttle after a couple of seconds of cranking. The less time between drives allows quicker starts with much less in the way of special techniques.
The first start in the spring is similar to the starting after weeks of not driving except that the plugs will be loose because of adding winter storage oil in spark plug holes. So initially I crank the engine with no plugs until I read oil pressure on the gauge and idiot light. Then plugs go in and it starts. A couple of springs ago I had a problem like howieb4 and it wouldn't start, no gas movement. I took the fuel pump apart to find nothing visibly wrong. Put it back on and it finally started with more cranking. I guess I didn't crank it enough with no plugs or with full throttle the first time. I think the 2 one way valves in the fuel pump allow gas to seep back towards the tank over time. They work well enough when the engine is running. but not good enough for extended downtime.
Brad a "clear fuel lines" search gets you this and a myriad of places. Search Results for clear fuel hose
 
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