mally002 Posted October 4, 2008 Share #1 Posted October 4, 2008 (edited) I did some searching and found lots of different info, but most was related to no spark. Here's a brief update and my problem. 1973 240z with roundtops.....(Thanks Tom) Over the last two weeks I have done the following: Drained all old gas and blew out the lines, new mechanical fuel pump, new filter, and plugs. Hooked up new intake manifold with the roundtops and attached all hoses, etc. Put 5 gallons of fresh gas back in and went for start up. Pulled choke and it fired up, ran at a very high idle for about 25 seconds then died. Tried restarting and it hits but wont run. Sprayed some starter fluid and it will start but then dies. Pulled off the fuel lines to the carbs and turned engine over, fuel spurts out. Whats the next step, anything I should try? I assume it's a fuel issue but everything to my non-mechanical mind look good. Thanks for any help. Quick edit.....I just pulled off the top of the carbs and noticed the rear carb was dry so I removed this piece..(see picture as I don't know the name, it's circled in Red). When I removed this piece it was dry also so I put a capfull of gas in there. The engine fired right up and ran for almost 2 minutes.....then as I eased the choke in it died, and now it won't even fire with starting fluid. The struggle continues. Also I noticed the coil was very warm, is that normal. I think I'm done for the day, maybe watching football will restore my brain. Randy Edited October 4, 2008 by mally002 Link to comment Share on other sites More sharing options...
MikeW Posted October 4, 2008 Share #2 Posted October 4, 2008 The part circled in red is the float bowl. The principle of operation here is quite simple. There's a float in the bowl. It's like the tank on a toilet. When the fuel level in the bowl drops the float drops which opens a needle valve which lets more fuel in. As the fuel rises the float causes the valve to cut of the supply. The net effect of this is to keep a constant level of fuel in the bowl which is then delivered to the carb through the rubber hose at the very bottom.The fact that your bowl was completely dry indicates a supply problem. I'd first check the other bowl. If it's full then the problem is not with the fuel pump or supply line from the tank, etc., but rather limited to the carb that's empty. The needle valve at the top of the bowl - it's screwed into the lid - can become stuck in the closed position which prevents that bowl from filling up at all. Link to comment Share on other sites More sharing options...
EScanlon Posted October 4, 2008 Share #3 Posted October 4, 2008 Correct me if I'm mistaken, but isn't there a small filter in the Banjo fitting that connects to the top of the float bowl cover? The needle sounds like the most likely culprit, but IIRC the banjo fitting filter (at least on the Sports) can also cause problems.FWIWE Link to comment Share on other sites More sharing options...
Force Fed Posted October 4, 2008 Share #4 Posted October 4, 2008 Float level isn't right, I just fought this same problem w/ my '72 for hours the other day Link to comment Share on other sites More sharing options...
xray Posted October 4, 2008 Share #5 Posted October 4, 2008 Yes, sounds like the float valve is stuck closed. Here's a fun test....remove the float bowl lid completely. Turn it upside down. Attach some flexible tubing to the fuel supply port. While blowing on the tube actuate the float manually and see if the valve opens and lets air through. Float level is determined by the distance between top of the float and underside of the float bowl lid. Adjust the float level by bending/straightening the metal tab attaching the float to the valve.Check what ID number you have for the carb itself. It should read something like HJG46W something. If it's R8 or R9, rear float level should be around 12mm (1972 rear carb) and front carb should be 16mm. If the last few digits are R3A or R4 (1970-1971), then float level should be set to 14mm. Link to comment Share on other sites More sharing options...
Sailor Bob Posted October 5, 2008 Share #6 Posted October 5, 2008 Do you still have the electric fuel pump hooked up? If so that may create a problem as well. I disconnected mine (it is still in the line (will remove in order of priority)) as directed by Bruce Palmer and it works fine. Had mine out for spin tonight, lots of problems, but none with power . Link to comment Share on other sites More sharing options...
mally002 Posted October 5, 2008 Author Share #7 Posted October 5, 2008 I'm going to attack it again on Sunday, taking in all the advice...Thanks for all the input.If you see a thread tomorrow labeled !@#$!@#$!#!$#!## you'll know I didn't fix it.......:sick:Also, is the fact that the coil was getting Hot an issue or is that normal. Link to comment Share on other sites More sharing options...
xray Posted October 5, 2008 Share #8 Posted October 5, 2008 How hot is hot? Anyhting that makes you say "Daggum, that's kinda hot!" probably represents a problem. My car's ignition (Pertronix, OEM BR, Flamethrower 1.5 ohm coil) does not get more than warm, even when driving in a hot day. I think most of the time a hot coil means there's too little resistance between /in the coil and the main circuit, as if you were running a 1.5ohm coil without a ballast resistor. Have you checked the primary and secondary resistance on the coil? Is the ballast resistor wired in correctly? Any idea on the coil's specs? Folks who have done ignition mods may be able to further help (like Dave, aka Zsondabrain). Link to comment Share on other sites More sharing options...
Force Fed Posted October 5, 2008 Share #9 Posted October 5, 2008 Yes, sounds like the float valve is stuck closed. Here's a fun test....remove the float bowl lid completely. Turn it upside down. Attach some flexible tubing to the fuel supply port. While blowing on the tube actuate the float manually and see if the valve opens and lets air through. Float level is determined by the distance between top of the float and underside of the float bowl lid. Adjust the float level by bending/straightening the metal tab attaching the float to the valve. , dude that's exactly how I did mine the other night, all the while saying to myself "I bet they would at me if they knew I did it this way BTW what is the best way to bend the tab w/o messing up the float? I think one of my floats is cocked upwards a bit from being bent (PO, not me). I slid a screwdriver shank under the metal bracket, in between it and the float, so I could bend the tab w/o pushing/ripping the bracket out of the foam float. I set mine by blowing through the hose and seeing where the air flow stopped coming through, since my one float is messed up and set properly is too high. Link to comment Share on other sites More sharing options...
mally002 Posted October 5, 2008 Author Share #10 Posted October 5, 2008 You guys are good.....It was the float valve.Engine fires right up now, although it sounds like an F-14 ready for takeoff, I have never heard a Z this loud and the fan is pushing alot of air.Choke is still sticking and my clutch is mushy, but at least it is now running, thanks again for everyone's input. Link to comment Share on other sites More sharing options...
Zs-ondabrain Posted October 5, 2008 Share #11 Posted October 5, 2008 Just make sure that you regularly pull the linkage bars and clean out the cups and pivot balls with a Q-tip or rag, lightly grease them, pull thelinkage swival on the firewall and clean the shaft and bushings and regrease them as well."A well oiled Machine" bla bla bla. Replace "oil" with grease and she'll be smooth as a babies butt.even regrease the pedal assembly while you're at it. and double check the strength of the return springs.Dave. Link to comment Share on other sites More sharing options...
Parman
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