KELMO Posted April 26, 2018 Report Share Posted April 26, 2018 Which is the same one I thought was in the engine compartment......D'OH. Thanks Charlie. :thumbup: 1 Quote Link to comment
DrvnDrvr Posted April 26, 2018 Report Share Posted April 26, 2018 Readily available on ebay https://www.ebay.com/itm/NEW-FUEL-FILTER-FOR-GASOLINE-ENGINE-FIT-FOR-NISSAN-DATSUN-620-720-PICKUP-TRUCK/112960921436?epid=8010510494&hash=item1a4cfedf5c:g:J~cAAOSwqoZa4Kqq 1 Quote Link to comment
Jwalth02 Posted April 26, 2018 Author Report Share Posted April 26, 2018 Kelmo, when I installed the new pump it eliminated the stock pump with the filter inside, the line comes straight out of the tank to the pump and I have not located a second filter in line yet. I will check for the one you show there Charlie. I did not get to work on it today, I was a little distracted by buying a 97 jeep wrangler... My to do list: Pull the fuel line off and open the bowl and blow air through Pull the Idle mixture screw and blow air through Locate secondary fuel filter and check/change Check float and make sure it's not flooded If all else is good check timing and verify wires again 1 Quote Link to comment
datzenmike Posted April 26, 2018 Report Share Posted April 26, 2018 You need to put the filter between tank and pump to protect the pump. The pump instructions probably said this. Take the idle cut solenoid out and remove the pointy pin and spring. I'm thinking the solenoid may click but not open to let gas down to the idle mix screw. You can always put it back later if this is not the case. Keep in mind that the idle mix screw has no effect if the engine is idling too high. The float has a lever on it that pushes up to close the needle valve letting gas into the bowl. You bend that 'tab so it closes earlier to set the fuel level. Place a large rag under the front of the carb to catch the gas when you take the front cover off. Directly behind the glass on the float hinge is a very small brass spacer so watch for it as it can easily fall off and then it's gone! Having a rag under it will catch it. With the spacer secured, slide the float towards you and off the hinge pin. You will have to push the needle valve up, to slide the float back in place under it. With the carb on the engine setting the fuel level will be trial and error. If it was off you can turn it upside down and let the float hang down holding the needle valve closed. Generally the float would be horizontal to the carb if set properly... this is hard to guesstimate by simply lifting the float with a finger. Expect to adjust a couple of time to get it right. 1 Quote Link to comment
Charlie69 Posted April 26, 2018 Report Share Posted April 26, 2018 I always have a filter before the fuel pump. Especially on 30 + year old vehicles. 1 Quote Link to comment
Jwalth02 Posted April 27, 2018 Author Report Share Posted April 27, 2018 Ok sorry for the confusion, the new pump came with a filter and yes I did install it. I say again, there is a filter before the pump. There is no other filter in the line after the pump. I just traced the lines all the way to the carb. I removed the needle and spring from the cutoff valve and no change but I am going to leave it out for now. I am going to go adjust the float now. 1 Quote Link to comment
Jwalth02 Posted April 27, 2018 Author Report Share Posted April 27, 2018 Ok. Just got done with my list (excluding timing) Adjusted float needle and made sure it wasn't flooded, pulled it all out and blew air through the portal from the fuel line. Pulled the idle mix screw and blew it out. Tried to start it and BAM! SHES ALIVE!!! Put the air cleaner back on, hooked up the hoses got ready to adjust the idle and sputter sputter die... Right back where I started except the fuel level is correct now. I did adjust it a little before putting the air cleaner in, I can't tell the rpm's cause my tach hasn't worked for years. 1 Quote Link to comment
datzenmike Posted April 27, 2018 Report Share Posted April 27, 2018 The air may have just pushed some dirt out of the way and it came back. Try the air again. 2 Quote Link to comment
Charlie69 Posted April 27, 2018 Report Share Posted April 27, 2018 Whenever blowing out carb ports it is best to blow backwards against the direction of normal flow. For example take the needle and seat out and and blow from the needle and seat out the fuel line inlet. same with the idle circuit. If you blow in the direction of flow you most likely will not get all the foriegn matter out. You could also be recontaminating it from dirty fuel lines. 1 Quote Link to comment
Jwalth02 Posted April 27, 2018 Author Report Share Posted April 27, 2018 Ok. Blew the idle and fuel circuits out again, reverse direction of flow as requested. Got it to idle until it warmed up and the choke fully opened. Started turning down the idle screw and it died again. I discovered when I put my finger over this port: It will run at idle, but with the hose hooked up it will not. That hose goes under the air cleaner and to this valve: Could this be my problem? 1 Quote Link to comment
Charlie69 Posted April 27, 2018 Report Share Posted April 27, 2018 Clean the valve it is probably stuck. or just cap the vacuum port and see how well it drives. 2 Quote Link to comment
datzenmike Posted April 28, 2018 Report Share Posted April 28, 2018 That's the temp sensor for the ATC Automatic Temperature Control. It senses incoming air temp and applies vacuum (or not) to the vacuum motor out at the end of the snorkel. This little flap gate mixes outside air and air warmed by the hot exhaust to keep the air going through the engine at around 100F. This allows the engine to perform like it's summer at all times of the year. Cold weather does not cause carb icing. If worried about thinner warm air not being good for performance keep in mind that at WOT wide open throttle the intake vacuum drops so low the vacuum motor doesn't work and the flap gate opens to allow only outside air in. Simple, good for mileage and drive ability. Follow that hose going out to the vacuum motor in the snorkel. Look for cracks or if it's disconnected. 1 Quote Link to comment
Jwalth02 Posted April 28, 2018 Author Report Share Posted April 28, 2018 Are you talkin this guy? Hose was split around the ends, I cut out the bad section and put it back on will try to run it and see what happens. 1 Quote Link to comment
datzenmike Posted April 28, 2018 Report Share Posted April 28, 2018 Vacuum may have leaked there or at the sensor end. Should be easy enough to pinch off sections to find the problem. 1 Quote Link to comment
Jwalth02 Posted April 28, 2018 Author Report Share Posted April 28, 2018 No luck. Pinched it off from the morot on the snorkel and it would idle for about two minutes them shut off. I'm at my wit's end with this thing... 1 Quote Link to comment
xxmass Posted April 28, 2018 Report Share Posted April 28, 2018 You said “when i put my finger over this port it will idle.” Plug that port. Then put something in the snorkel to keep the flap open, maybe a screw from the outside. 1 Quote Link to comment
xxmass Posted April 28, 2018 Report Share Posted April 28, 2018 When you adjust the idle air/fuel are you starting at full lean? After it dies when idling what does it take to start it back up? 2 Quote Link to comment
datzenmike Posted April 28, 2018 Report Share Posted April 28, 2018 If plugging that port allows it to idle then what ever is connected to it must be leaking. The hose to the temp sensor, the temp sensor, the hose to the vac motor or the vac motor. 1 Quote Link to comment
Jwalth02 Posted April 29, 2018 Author Report Share Posted April 29, 2018 So... Just to eliminate fuel again I installed a filter right before the hard pipe to the carb. I ran it until it died three times blowing the mix screw out each time. Now I have it idling but only with the mix screw between 5 1/2 to 6 turns out. It is still a bit of a rough idle and I can't say what the rpm's are without a working tach. I am making progress though... My question, is this mix screw setting too high? If so what do I need to do from here? 1 Quote Link to comment
Jwalth02 Posted April 29, 2018 Author Report Share Posted April 29, 2018 If plugging that port allows it to idle then what ever is connected to it must be leaking. The hose to the temp sensor, the temp sensor, the hose to the vac motor or the vac motor. When I had my finger over it, it would idle but then it went back to stalling. So I think I was just chasing a ghost with a bout of clean fuel... 1 Quote Link to comment
Jwalth02 Posted April 29, 2018 Author Report Share Posted April 29, 2018 Oh my God... Got my tip cleaners out, pulled the mix screw out and ran the one that fit the best through the idle jet. Now it's idling kinda high but so far I have the needle back in to there it's 4 turns out... Is there a way to post videos so I can show you what it's doing now? 1 Quote Link to comment
Charlie69 Posted April 29, 2018 Report Share Posted April 29, 2018 Put a Weber on it and enjoy life. 2 Quote Link to comment
datzenmike Posted April 29, 2018 Report Share Posted April 29, 2018 Oh my God... Got my tip cleaners out, pulled the mix screw out and ran the one that fit the best through the idle jet. Now it's idling kinda high but so far I have the needle back in to there it's 4 turns out... Is there a way to post videos so I can show you what it's doing now? Set the idle speed as low as you can. 1/ Turn idle mix screw in until the idle worsens then out till it worsens. 2/ Pick a spot about half way between where the idle is fastest and smoothest. 3/ Turn idle speed down as low as possible. 4/ repeat 1/ 2/ 3/ as many times as needed until you cannot improve the idle quality and the idle speed is 750 or so. Done. 2 Quote Link to comment
Jwalth02 Posted April 29, 2018 Author Report Share Posted April 29, 2018 4/ repeat 1/ 2/ 3/ as many times as needed until you cannot improve the idle quality and the idle speed is 750 or so. Done. Umm hard to tell exactly like I've said a couple times without a working tach... Right now it's as good as I can get it, just sounds kinda rough but at least it's running. 1 Quote Link to comment
Charlie69 Posted April 29, 2018 Report Share Posted April 29, 2018 Listen to the engine, you do not need a tac. 2 Quote Link to comment
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