Trouble with my 74 620

1972-1979 Datsun 620 forums. All 620-specific topics and discussion can be found here.
dfresh777
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Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
Location: Portland, OR
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Anyone Have a quick solution to why the Carb would have so much presure its shooting gas out of the top ports? i dont have an account to upload a video or i would.


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PEZi
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wrong fuel pump???

dfresh777
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Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
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Is that really possiable? is there a way to adjust a manual fuel pump?

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PEZi
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it is possible... i'm by no means saying that's the problem at hand though... but as a simple answer to the problem it definitely could be... a pump that is making too much pressure, like one intended for fuel injection use can blow fuel through the system like nobody's business

no idea what pump you have, nor if its adjustable

dfresh777
Posts: 36
Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
Location: Portland, OR
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i will go see if i can't find a part number on it or email a picture of it. i was wrong about it being replaced, it still the same one from when the truck was given to e before it stopped running.

dfresh777
Posts: 36
Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
Location: Portland, OR
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I think it is partly the fuel pump. i found one for a fair price here is the part number 1096 just need to know if this will do the trick? i check it with two auto parts stores in Portland, OR and they had the same thing for the same price. i am really trying to stay away from pulling the carb off

dfresh777
Posts: 36
Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
Location: Portland, OR
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Call me Crazy, here is a idea that just popped in my head this morning, what if i got a valve that i can adjust the fuel before it get to the carb? if you think this would work let me know and where i should put it before the fuel pump or after right before it enters the carb.

dfresh777
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Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
Location: Portland, OR
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Okay looking up information trying to see if this fuel pump can be adjusted its KYOSAN 5-1 DENKI made by KYOSANDENKI. if anyone has better luck than me please post the link you found information on. thanks

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Rev_D21
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Confused: Why would fuel pressure increase once the engine is warm? I am thinking you have a choke issue or the carb itself wasn't assembled properly, as much as you don't want to hear that. If you are still convinced that fuel pressure is to blame Summit sells inline fuel pressure gauges for less than $20 that will tell you for sure if your pump is the problem or not. IMO, I once had a mechanical pump Datsun Z22, the pump can't change pressure as a result of engine temp, only engine speed and even that only changes volume. I think you have a mess of a carb there and you should be directing your attention to that first. I bet if you change the pump you will have the same results.

dfresh777
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Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
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you are right, that is the last thing i was wanting to hear, but as you have read on my postings it was the first things someone else said. sadly i think i might have to pull it apart. only thing is do i have to replace all the gasgets when i take it apart? also i am going to need a photo on how it goes back together correctly if anyone knows a good link to get a good photo that would be great.

dfresh777
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Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
Location: Portland, OR
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so today i had a friends dad come work on the truck with me, we pulled the float cover off and it is missing a spring. also noticed it was leaking fuel a little due to a bad gasget. so now i have to clean it and rebuild it.

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PEZi
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awesome! good luck man!

dfresh777
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Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
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we did get it running yesterday for a little bit. the carburater brand is Hatachi not sure what the model is yet still looking.

dfresh777
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Joined: Fri May 07, 2010 8:28 pm
Car: Datsun 620 Pickup
Location: Portland, OR
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okay fixed the float put the spacer and clip in that was missing and tightened the bolt that was allowing fuel to leak, think i need to get it timed correctly so that it will firer over


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