Okiedoke, guys, I'm at a point where finally I need to turn to the web for some help. I've been gradually replacing old bits on the the Sambar (specs in Signature), basic tune up maintenance (plugs/wire/spark plugs, timing belt/water pump, alternator belt, oil and fluids, fuel filter, air filter, and checked charcoal canister) just due to age. For the few months of ownership, it's not gotten great fuel economy (maybe 15mpgs, never took a precise measurement), and exhaust got to smelling pretty rich. I figured maybe the old carburetor probably needs a cleaning, so I ordered a rebuild kit, and ordered a factory rebuilt carb so I could have one on standby. Today I installed the factory rebuilt carburetor. The install went well, and I'm positive all the hoses are all back in place, took pictures beforehand and labeled each hose and mount point during removal. Filled up the truck with new coolant, and went to start it. On second try, fired right over. Initially the throttle cable was too tightly adjusted, so had to back that off, and it settled into a good sounding idle. I have a tach installed, so I was able to see it settle into 8-900rpm after warming up. Fast forward, took the truck out for a drive. It drove fine in my estimation, it was reaching rpms it wouldn't get to on the old carb, seemed peppy enough. When I got home, I parked it on a slight incline, cab facing up. After maybe 5 minutes, I went to start it back up, and it fired over, but over maybe half a minute, it slowly sputtered itself out. Got it to fire over once more, sputtered back out. Quickly found I'd flooded it, so gave it time to set and pushed into my carport. Cleaned spark plugs and let everything air out for a bit. During the downtime, loosened the throttle cable a little more to have just a bit of slack in the cable, thinking since that was the only adjustment I'd made since installing the carb, maybe it contributed to the flooding. After getting the truck started again, I tried to recreate the issue. Parked the truck on an incline, cab up, let it set, rinse and repeat, seeing if I could get it to flood. Did not happen. It would start, sometimes taking a time or two to turn over, but it would start and run without sputtering out. I let the truck set for a few hours as I got some other tasks done. When I came back to it, it started on second try. Idle was ok, slightly rough at first but smoothed out inside of a minute. I rode around for about 20 minutes and stopped to visit my folks. We chatted for a bit, and the truck sat idling for maybe 20 minutes. When I got back in the truck and pressed the gas, instead of rpms going up, it sputtered and lost rpms. Pressed gas again after it managed to get back to a decent idle, and it sputtered and died. Had a time getting it to turn over again, and as soon as I managed to goose it into life, went straight home. There was a pretty good puff of black smoke at startup, and an observation was made that it did smell a bit of fuel at the exhaust while idling. During the drive, from what I could tell, it was running ok. It didn't threaten to die or anything of that nature going home. I haven't done anything further with it since getting home, spending my time instead trying to research what could be the issue. Do factory rebuilds require any fine tuning? I've had some advice from a few folks today suggesting the first issue could have been the throttle cable too tight, and I've had suggestions that I should open the new carb up to verify jetting, floats, and so forth. I'm hoping to not have to do all that on a factory rebuild, especially after having already installed it, but if there's a consensus to that effect, I'll just have to bite the bullet. I've seen the floats in the old carb, and can get my head around how they should be working based on the online manual. I don't know a thing about the jets, and don't understand what I need to be seeing to verify if they're adjusted correctly. And, I'm not even sure if the carburetor is the culprit at this point. The only other thing I can think is maybe vacuum lines? Last week I pulled them off to clear them of any debris. Wasn't anything to clean out. One of the lines today did have a pinhole, though it was over the male end connection. I did trim that piece off since I had enough hose. I've considered swapping all the lines out just due to age, though they're in remarkably good shape overall. I would be thankful for any and all ideas and technical assistance, guys, thanks for reading.
I don't think you need to go around fooling with the float cause it is a factory rebuilt carb, this sounds like a matter of mixture. What you have to consider is, in Japan they have very different elevation levels, and climate compared to North America. The mixture needs to be different. When the carb was factory rebuilt, it was put into factory specs which is good for Japan, not so much for North America or Europe. Car retailers did mixture fine tuning before delivering carbed cars to customers when they were sold as new. Used cars don't usually get that so you have to do it yourself. Things inside the carb are last things to consider on a rebuilt carb. Kei cars in general use very similar carbs, so I'd expect there is an MAS screw somewhere on your carb, adjusting that will tell if it is a matter of mixture.
Thank you VERY much for your reply. The bit about fine tuning happening at retailers is something I did not know, good information! That would make sense, and gives me something to look at. Reflecting on the issue this morning, I'm making a completely uneducated guess that the carb is, for lack of a better way to describe it, 'loading up' on fuel faster than burning it, causing the instance of flooding, and later bogging itself out.
Coming back to this thread, here's where I'm at. After letting the truck warm up, I adjusted the mixture screw. Haven't messed with high idle or warm idle screws since it starts and settles at good rpm's, ~800 steady when warm. Problem I'm facing is that while letting it warm up, it gradually flooded itself before getting to the point of being able to adjust the screw. I managed to get it to restart and tried leaning out the mixture. The last behavior I got out of it, after trying to adjust the mixture screw, is that it'll idle at ~800 for about 10-15 seconds, and start to flood itself out. Have not found a sweet spot where it won't keep trying to flood. Do I perhaps need to allow for some time for it to 'unflood' before taking another crack at it? Or, heaven forbid, am I looking at a potential other issue?
OK, ready to call this one solved! Yes, it was a matter of adjusting mixture, just had to not let the carb flood and get the mixture leaned out. Pretty much futile to try adjusting mixture on a carb that's flooding. Had to fine tune the idle as I went, but now I have the idle and the mixture happy. Easily the best the truck has run since I acquired it.
Hi, I know this is an old thread but hope I can can still get a response. I have also just put in a rebuilt carb and having the same flooding issue. Could you confirm which is the adjustment screw to lean out the mixture? (as there are way the many adjustment screws on this thing I'm guessing #3? (attached picture) https://photos.app.goo.gl/UZeUdf3fSNfdY2Fo6
It's always been my experience with carbs that they are rarely ever set up correctly out of the box. They need to be tore down cleaned then rebuilt checking and verifying the float height and drop. Excessive fuel pressure could can also push the needle off their seat causing a flood condition.
