Spirit7 Posted October 22, 2013 Report Share Posted October 22, 2013 Hi all, I recently picked up a 260z for $250. The car sat for at least 12 years, probably more. I'm trying to get the thing started, but I just don't really understand carbs all that well. I started out cleaning the fuel tank and replacing the pumps (electric and mechanical), I had an issue with my original carbs spewing gas from the front, so I found a set on ebay. I can get the car to run for a few seconds off of starting fluid. The pump is working, and the sight glass on the carb is half full. I have downloaded the FSM. I'm a little confused as it does not give me a starting setting for the carb. It starts out saying to warm the engine first (can't do that with it not running, lol). I also looked in the trouble shooting. For "engine does not start" it says... Overflow...I don't have fuel overflowing from the carb, so I don't think it's this. No Fuel Fed to Engine...the fuel pump is working, and there is fuel in the carb. (Possibly bad needle valve??? How would I check this?) Improper Idling Adjustment...It says to readjust, but again, I don't know where to start with the settings. Defective Suction Piston.... Is the suction piston the large metel piece inside the carb that can be raised form the front intake side of the carb? Quote Link to comment
dr.feltersnatch Posted October 22, 2013 Report Share Posted October 22, 2013 You replaced BOTH fuel pumps? What carbs do you have? Pics if you don't know. Did you replace the fuel filter, and of course the fuel! Quote Link to comment
Tristin Posted October 22, 2013 Report Share Posted October 22, 2013 I would also either replace all the lines or blow them out. Your pump may be working fine, but with clogged lines it wont suck anything but gunk up. Quote Link to comment
Spirit7 Posted October 22, 2013 Author Report Share Posted October 22, 2013 Yeah, new fuel, new filter, blew out the lines. I can disconect the line running to the carb and crank the car, gas definitely comes out. I replaced them with new flat top carbs. I really think the issue has to be in the carbs somewhere, but like I said, I don't really know where to start with the settings to ensure at least a rough start up. Quote Link to comment
Tristin Posted October 22, 2013 Report Share Posted October 22, 2013 No experience with SUs, but here is a guide over on Nicco. Maybe this can help out: http://www.nicoclub.com/archives/2-write-ups-on-tuning-su-carbs.html Quote Link to comment
Sealik Posted October 22, 2013 Report Share Posted October 22, 2013 Yeah, new fuel, new filter, blew out the lines. I can disconect the line running to the carb and crank the car, gas definitely comes out. I replaced them with new flat top carbs. I really think the issue has to be in the carbs somewhere, but like I said, I don't really know where to start with the settings to ensure at least a rough start up. Are the choke cables hooked up...functional? Pics....? http://www.zcarz.us/TechnicalInformationPageCarburation.htm Quote Link to comment
dr.feltersnatch Posted October 22, 2013 Report Share Posted October 22, 2013 http://www.youtube.com/watch?v=ASeMfXfjNpw different car but same basic idea Quote Link to comment
datzenmike Posted October 23, 2013 Report Share Posted October 23, 2013 I don't think the SU had a sight glass. The 260z also had the infamous flattop SUs. Quote Link to comment
MikeRL411 Posted October 23, 2013 Report Share Posted October 23, 2013 I don't think the SU had a sight glass. The 260z also had the infamous flattop SUs. Right! SU carbs do not have sight glasses. Quote Link to comment
MikeRL411 Posted October 23, 2013 Report Share Posted October 23, 2013 Hi all, For "engine does not start" it says... Overflow...I don't have fuel overflowing from the carb, so I don't think it's this. Check at the end of the overflow tubing, normally flows to ground unless you have a return to tank connection. No Fuel Fed to Engine...the fuel pump is working, and there is fuel in the carb. (Possibly bad needle valve??? How would I check this?) Under the main carb housing is a protruding wire. This is connected to the overflow valve and the outlet flow control valve. After siting for so long the outlet may well be clogged with evaporated crud. Feel below the float chamber and jiggle the wire until you are tired. Have a beer and do it again to clear the float assembly/ Improper Idling Adjustment...It says to readjust, but again, I don't know where to start with the settings. You need to look at the referenced NICO site. Dependent on the model of Hitachi SU you have. Defective Suction Piston.... Is the suction piston the large metal piece inside the carb that can be raised form the front intake side of the carb? YES! Also check to see if there is any oil in the damper. Unscrew the black plastic assembly on top and check against the inscribed fill line. Quote Link to comment
Spirit7 Posted October 23, 2013 Author Report Share Posted October 23, 2013 Ok, I pulled the plugs today, looks like cylinders 3 4 and 5 are black and a little wet (it dries, so it think it's fuel), but 12 and 6 look new still. I'm not sure what that could indicate though. I'm not sure how those cylinders could not be getting fuel, and if I am getting fuel, shouldn't the car start since it will run a few seconds off of starting fluid? Quote Link to comment
datzenmike Posted October 23, 2013 Report Share Posted October 23, 2013 Hi all, I recently picked up a 260z for $250. The car sat for at least 12 years, probably more. I'm trying to get the thing started, but I just don't really understand carbs all that well. I started out cleaning the fuel tank and replacing the pumps (electric and mechanical), I had an issue with my original carbs spewing gas from the front, so I found a set on ebay. I can get the car to run for a few seconds off of starting fluid. The pump is working, and the sight glass on the carb is half full. . So this begs the question.... what carbs did you buy off e-bay that have sight glasses????? Quote Link to comment
Spirit7 Posted October 24, 2013 Author Report Share Posted October 24, 2013 . So this begs the question.... what carbs did you buy off e-bay that have sight glasses????? They are the flat top carbs off a 73. As far as I can tell, they are the same as 74 but without the coolant lines running through it Quote Link to comment
Sealik Posted October 24, 2013 Report Share Posted October 24, 2013 What sight glass are you referring to????? Have a camera...????? Snap some pics..... Quote Link to comment
Sealik Posted October 24, 2013 Report Share Posted October 24, 2013 Also....did you set the 'carbs' up as stated in that link I provided? Quote Link to comment
Spirit7 Posted October 24, 2013 Author Report Share Posted October 24, 2013 What sight glass are you referring to????? Have a camera...????? Snap some pics..... Here's a pic of one of the carbs that was originally on the car. the sight glass has been circled. Quote Link to comment
datzenmike Posted October 24, 2013 Report Share Posted October 24, 2013 How interesting is that? Did not know this. Quote Link to comment
Spirit7 Posted October 24, 2013 Author Report Share Posted October 24, 2013 How interesting is that? Did not know this. I'm really thinking about ditching the flat tops altogether purely based on the fact that I can't hardly any information on them. Quote Link to comment
datzenmike Posted October 24, 2013 Report Share Posted October 24, 2013 This is what Z Therapy thinks about the z car flattops..http://www.ztherapy.com/ This is not a carb-It is a boat anchor!June1972 240Z to all 260Z's (US) Flattop "Hitachi"Evil things, these square mouthed carbs.If you have these carbs on your 240Z-trash them and get ZTherapy SU's. You will experience a huge increase of power, mileage, and less breakdowns! These are commonly referred to as "Hitachi's" or "Flattops". The dome shoulder is square, and the float bowl is on the bottom. These carbs are not acceptable as cores. Please pay the core charge instead of sending these in. The round SUs work great, but by late '72 they couldn't come close to meeting the increasingly stiffer emissions standards. The flattop was overly intricate and 'smog laden'. Customers with problems with them would drive into the Nissan dealers and mechanics would run out the back. No one wanted to deal with them. Today there are not many around because most tore them off and threw them away. Earlier SUs were substituted. Quote Link to comment
banzai510(hainz) Posted October 24, 2013 Report Share Posted October 24, 2013 I gave a set away Quote Link to comment
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