picking up the 620 today. BUT, i have a couple questions

[btbammer]

So I was suppose to pick up the 620 yesterday but stuff came up. Im getting it today though I think. BUT before I do, I had a couple questions/concerns. The picture is of course nicer than up close, No issue there, but there are issues he didn't specify that are wrong.

 

Here's the deal :

 

Upon test driving it, im driving, shifting etc but When I put in the clutch it dies everytime. So when the rpms are high then dropped it kills it.

 

There Is no airfilter housing on it. (He said it runs better without it on?)

 

The carb has an issue obviously, the lip/flap/butterfly was removed by the previous owner I guess?

 

My question is, is this a easy quick fix?

[btbammer]

I know I shoulda got some photos wen I was there. Im a re re. :(

[Eagle_Adam]

There Is no airfilter housing on it. (He said it runs better without it on?) - that may be true but its not the right way to do it IMO

 

The carb has an issue obviously, the lip/flap/butterfly was removed by the previous owner I guess? - what kind of carb? Webber or hitachi? SU or downdraft Ect...

[btbammer]

Also, it is completely gutless in the first couple gears. Is That because its a 75 620? Or becAuse of the improper gas/air mix aka missing airbox/missing flap on carb?

[btbammer]

:( [quot

e name=Eagle_Adam' date='14 July 2011 - 09:46 AM' timestamp='1310661986' post='512383]

There Is no airfilter housing on it. (He said it runs better without it on?) - that may be true but its not the right way to do it IMO

 

The carb has an issue obviously, the lip/flap/butterfly was removed by the previous owner I guess? - what kind of carb? Webber or hitachi? SU or downdraft Ect...

 

Not sure wha type of carb it is, it looks like THE stock one that comes on the 75 620 L20B

[banzai510(hainz)]

could be loose carb idle jet plugged/mixture screw needs adjustment

Timming could be off or distributor /oil pump off a tooth

Timming chain could be off one tooth.

 

IS this a EZ fix?????? Its says you own a 510 and 620 already you should know.

 

 

read everything on this page

http://www.olddatsuns.com/620tech.htm

[btbammer]

I do, but Ive never had to work on the carbs..

Gotten lucky up I til now.

 

Is it an ez fix? Or just I just replace the carb? I can do either.

[btbammer]

could be loose carb idle jet plugged/mixture screw needs adjustment

Timming could be off or distributor /oil pump off a tooth

Timming chain could be off one tooth.

 

IS this a EZ fix?????? Its says you own a 510 and 620 already you should know.

 

 

read everything on this page

http://www.olddatsuns.com/620tech.htm

 

Thanks! This will definately help.

[Eagle_Adam]

if you can afford it i would replace the carb with a webber, if it is a webber rebuild it and ur good to go

[Z chopper]

Because of the improper gas/air mix aka missing airbox/missing flap on carb would be my guess as to the gutless performance

[Z chopper]

replace and rebuild the one on it right now so that you know how to rebuild a carb in the future.

[Wide14u]

i say go get a weber

[btbammer]

I have a fresh rebuilt 4 barrel holley out if my monster v8 van. Would that work!?! :o

 

Hmm..

[wildmaninid]

I have a fresh rebuilt 4 barrel holley out if my monster v8 van. Would that work!?! :o

 

Hmm..

Yea, just throw some duct tape over the secondaries and go for it! A carburetor is just a metered fuel leak, so why not?

[btbammer]

I ask because i've heard of it working. But thanks for the solid suggestion boss.

[pharouh]

The p.o. took off the air cleaner and maybe the choke? To make it run better? Makes you wonder what other improvments he made..

 

If the price is low enough,buy it! It's time for you to learn engine repair! :D

[btbammer]

I am getting it for cheap and "runs and drives" fine, until you push in the clutch..

 

then it dies..

 

I guess ill just have to swap carbs and rebuild it.

 

Maybe put another butterfly and air filter on it and see if that fixes it (wishful thinking I know)

 

we shall see

[btbammer]

i say go get a weber

 

Any suggestions on where to pick one up? I would rather just do a weber.

[datsunaholic]

Likely the main problem is it has a huge vacuum leak. Putting the air cleaner on and the choke would cause a restriction (normal) BUT with a big vacuum leak it'd pull more through the leak, making it run very, very lean. Which it already is, explaining the lack of power AND the lack of idle. However a totally plugged idle circuit will have similar symptoms.

[btbammer]

http://www.webercarbsdirect.com/ProductDetails.asp?ProductCode=WK657&CartID=1

 

Looks like im going this route.

Ill look into the vacuum leak/ plugged idle circuit theory.

[Wide14u]

but before you go buy this carb show us some pics of your truck

[btbammer]

Maybe the brake booster has a hole? Ill test tonight.

[btbammer]

I promise ill post some pics tonight as well.

[btbammer]

So my neighbor and I messed with the carb last night, the P.O. hag it running Sooo lean. So I now have power in 1&2nd gear. Thank god.

 

The distributor was turned all the way up etc. Put it closer to middle

 

Had no fluid in the back brakes or clutch.

Brakes need bled but my booster isn't dead so that's good.

 

Neighbor is bring me a new "return to idle plug" he thinks its bad.

Hopefully that solves my "clutch engaged rpm drops engine dies" problem.

 

We will see.

 

He says "screw weber!!" "Those hitachi carbs are better!"

 

But im still getting the weber :) haha. And selling the hitachi to him. good deal :)

[btbammer]

Still really confused on the butterfly missing though. Also po said it was a bitch to start cold. After last nights adjustments and 5-6 good pumps its fired right up :)