datzenmike Posted May 27, 2013 Report Share Posted May 27, 2013 Can you buy these from Rockauto/NAPA in the states? Or anywhere else, without buying a complete rebuild kit? My goon falls on it's face on take offs. Quote Link to comment
LenRobertson Posted May 27, 2013 Report Share Posted May 27, 2013 I've never heard of finding them outside of a kit, but I hope I'm wrong, since I want one too. This is for a DHC 340? I rebuilt mine, but I had robbed the accelerator pump for my 200SX. So I reused the old one. The pump rubber looks just fine, but when giving it throttle coming off idle, it has a BIG hesitation. I have to feather the gas to get beyond that, then it accelerates and runs fine. Does that sound like your symptoms? I got up this morning ready to swap on a used Weber 32/36, without rebuilding it (have a kit, but I'm lazy). Somehow that seems a guarantee I'll be taking it off again right away and putting the kit in it. It just started raining, so I'm safe from my laziness for awhile. Len Quote Link to comment
datzenmike Posted May 27, 2013 Author Report Share Posted May 27, 2013 Yup. Just above idle right where you want to be when trying to glide away from a stop in no hurry. Seems to be right where the clutch grips and there is a small drop in RPMs right there and it balks. The only other thing you can do is rev higher and slip more. When working right it's seamlessly smooth. I remember they used to be made of leather. I was told once that it was kangaroo hide that wouldn't dissolve in gas or something. Ever hear that??? Quote Link to comment
Sealik Posted May 28, 2013 Report Share Posted May 28, 2013 I have a kit and never used it...although I did swap the new pump into an old Hitachi which is now in the back fourty somewhere. I think I have about a dozen Hitachis....some good....some bad. No need for them anymore.......<.......Webers Quote Link to comment
LenRobertson Posted May 28, 2013 Report Share Posted May 28, 2013 Just back from a test run in the 510. I always hope problems will cure themselves while the car is sitting. But it almost never happens. I tried really getting on it at low speed and it does a pretty violent bucking until I back off. Maybe tomorrow I'll try swapping the accelerator pump out of the SX carb and see if it improves the 510. I guess I could try the pump out of another dead Hitachi. There are several laying around here. At least they are easy to change. I remember when accelerator pumps were made of leather, but I never knew what kind of leather. There are some Ratsun members in Oz. Maybe one of them could pour some gas on a kangaroo and see what the reaction is. I still may try the Weber on the 510 if swapping pumps with the SX doesn't work. But I hate to admit I'm not smart enough to fix a Hitachi. It may be true, but I don't want to admit it. Don't want to spend $25 on a carb kit just to get another pump though. I'd spend the money if I knew for certain that would fix it. Also, this carb runs great at higher RPMs. Len Quote Link to comment
Zeusimo Posted May 28, 2013 Report Share Posted May 28, 2013 Later Chevy S10's And 720's Use Hitachi Carbs Different Styles But Accelerator Pumps Are The Same Just Go To The JY You'll Find A Nice One Quote Link to comment
LenRobertson Posted May 28, 2013 Report Share Posted May 28, 2013 datzenmike - I don't know if you've already checked the inlet and outlet balls to the accelerator pump chamber. The inlet ball is easy - it is the bottom of the pump chamber under the coil spring. I've shot carb cleaner down there (and it usually sprays back in my eyes. Good to hold a rag over the top of the chamber while spraying), and poked the ball with a jeweler's screwdriver to loosen it. To get to the outlet check ball, the top must be taken off the carb. On top of the carb main body over near the acccelarator pump is a plug with a screwdriver slot. Under the plug is a tiny coil spring, a brass weight, and the check ball in the bottom. Again, spray carb cleaner and make sure the ball isn't stuck. There also could be a piece of crap in one of the passages in the pump circuit. datzenmike, I'm pretty sure you already know all this, but it might be useful to someone else. As I mentioned in a PM, I ordered a new carb kit to get a new accelerator pump. But the Weber is lurking nearby, waiting for a chance to retire the Hitachi. Probably what I should have done last Fall when I first had trouble. Len Quote Link to comment
datzenmike Posted May 28, 2013 Author Report Share Posted May 28, 2013 I haven't had this carb apart as it ran, just not quite bad enough. But this year it seems worse, maybe driving will loosen it up. Yes there are two check balls, one way valves really. Gas can dry in the accelerator pump cylinder and get all sticky shellack. I've cleaned that shit out before on my Z24 carb. Maybe I'll have a poke around soon. Quote Link to comment
LenRobertson Posted May 28, 2013 Report Share Posted May 28, 2013 It might be worth a try to remove the accelerator pump, spray carb cleaner down into the pump bore, then stick the pump back into the bore and just push it down by hand (no need to hook up the pump arm). Do this a couple of times and (in theory) carb cleaner should get to the outlet check ball, without having to take the top off the carb. I'm not sure what carb cleaner does to the pump rubber, so pumping some gas on through to rinse out the cleaner might be a good idea. But I've done all this and I'm back to thinking I need a new accelerator pump, even though the old one looks fine. Len Quote Link to comment
LenRobertson Posted June 4, 2013 Report Share Posted June 4, 2013 Update on my hesitating coming off idle Hitachi 340. My cheapo eBay carb kit arrived this morning, and I installed the accelerator pump from the kit in my 510 carb. I just returned from a test run/annoying the town with the 510 noise. It is much improved with the new pump, although still a very slight hesitation coming off idle. I remember years ago a mechanic talking about bending the accelerator pump link coming up from the throttle shaft just slightly to get the best stroke on the pump. I may fiddle with doing that, or swap the link from another 340. Or I may just live with it the way it is for now and think about the Weber option sometime in the future. Len Quote Link to comment
RTB Posted June 5, 2013 Report Share Posted June 5, 2013 As a newb I have no clue what's going on in this thread but it makes me worry that I'm going to have acceleration problems since I'm putting in a l20b. But I'm running 44mm mikuni solex Quote Link to comment
bananahamuck Posted June 5, 2013 Report Share Posted June 5, 2013 As a newb I have no clue what's going on in this thread but it makes me worry that I'm going to have acceleration problems since I'm putting in a l20b. But I'm running 44mm mikuni solex What they are talking about is a internal part of a carb not working correctly, not the L20b itself ,.. And the OP being a cheap ass Datsun guy.. :D Quote Link to comment
RTB Posted June 5, 2013 Report Share Posted June 5, 2013 I thought you had to be a lil cheap to own a Datsun Quote Link to comment
HRH Posted June 5, 2013 Report Share Posted June 5, 2013 Mike, a carb rebuild kit is about $28-$50 usd for your carb. The accelerator pump gasket you're looking for is part no. 24256, line code (CRB). There are 4 in the Spokane dc. Sorry I didn't comment earlier. Accelerator pump gasket by itself is about $11. Quote Link to comment
datzenmike Posted June 5, 2013 Author Report Share Posted June 5, 2013 I can make a gasket. I need the plunger or piston that pushes the gas ahead of it. 16151-U6800 Quote Link to comment
arizonajones Posted December 21, 2013 Report Share Posted December 21, 2013 Hi all, hopefully this is the right thread for this question: I've noticed a small fuel leak coming from the top of my accelerator pump. I rebuilt the carb about 3 months ago - new accelerator pump and gasket. In the last month my gas mileage has gone crappy and I noticed the leak very recently. I switched the pump to the one that was on there originally (still in good shape) and it didn't really change anything. Reset and re-tightened the leather gasket and the metal cover over it. Still no dice. Does the gasket at the top have to be leather? Can I make one out of rubber? Should fuel even be able to get that high or should the rubber seal on the pump keep it tight enough not to squirt out of the top? Quote Link to comment
datzenmike Posted December 22, 2013 Author Report Share Posted December 22, 2013 Gas will dissolve (or perish) rubber. It would have to be cork or a neoprene gas resistant synthetic to last. The leak would have to be major to affect the gas mileage. Likely the choke is on more from the cold is all. Quote Link to comment
dr.feltersnatch Posted December 22, 2013 Report Share Posted December 22, 2013 mike did you find your parts? i think i have a rebuuild kit out in the garage if you still need it Quote Link to comment
datzenmike Posted December 22, 2013 Author Report Share Posted December 22, 2013 Me? Quote Link to comment
dr.feltersnatch Posted December 22, 2013 Report Share Posted December 22, 2013 Me? ya. you were looking for an accelerator pump right? old thread so i am sure you got it fixed by now Quote Link to comment
datzenmike Posted December 22, 2013 Author Report Share Posted December 22, 2013 Rory at the last Canby gave me half a dozen. He (as always) had trays and tables covered in small Datsun parts. It would take all afternoon to go through them. What a guy! Thanks for the offer, but I should be good for life now. Quote Link to comment
arizonajones Posted December 22, 2013 Report Share Posted December 22, 2013 Gas will dissolve (or perish) rubber. It would have to be cork or a neoprene gas resistant synthetic to last. The leak would have to be major to affect the gas mileage. Likely the choke is on more from the cold is all. Thanks Mike. Good to know Quote Link to comment
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