Im having issues with my Hijet truck that has an 993cc 3 cilinder carburated engine (CB41). I bought it for cheap and it had a seased up camshaft, so i thore the whole engine apart with my dad and repared it. The previous owner told us that it was running right before the camshaft seased up, however now i can't seem to make it run right. what happens: The engine starts good after just pumping the gas once when the choke is on and when its still cold then it keeps running great until after 1 to 5 minutes it just stalls out. Even when i try pumping the gas or after it has reached the right temperature and the choke is on. I've already checked all the vacuum lines and it all matches with the workshop manuals and they are all right, the carburateur has been fully cleaned and all the gaskets are still in good shape plus i also tried adjusting the distributor timing and the air mixture screws. I have no clue what the cause is of this problem but maybe someone has some tips or tricks? Thanks in advance and apoligies for my bad English.
Sounds like the choke isn’t disengaging, and it is getting too rich to keep running. Having not seen the bigger engine, I can’t say for sure, but generally the chokes on air controlled by a wax motor. When the engine is cold the wax contracts, and when the car warms up the wax expands, pushes on a plunger and disengages the choke.
Are you talking about the picture that i have send in the attachment?(btw the picture is from an second carburateur that i have laying around, it is the exact same type its just a bit filthy but the other one is clean.) Because ive seen the mechanism work when the engine was running. https://prnt.sc/112lek4 https://prnt.sc/112lejz
That looks like the wrong side of the carburetor. I think the choke is on the other side of the throttle shaft.
The round highlighted part is the place where the choke cable attaches to, and the green part under it keeps the trottle engaged when the choke is turned on and the pin that slides into the slot is what i believe the automatic choke that controller what closes the choke automatically when the engine gets on temperature. However i don't think the choke is the problem unless its something with the vacuum since the engine still stalls even though it is on temperature and with the choke fully turned off. https://prnt.sc/112nctv
What you describe generally indicates a too rich mixture once the engine warms up, and the usual suspect is the choke. Have you pulled a spark plug to check how it is burning? If they are sooty, it indicates a very rich mixture. There are pictures online. Are you sure that you have the choke properly adjusted? Is the choke blade fully open with the choke off? What is the idle speed set too when it is warm? The EF engine in my Hijet is set to 950-rpm, when warm.
I have pulled the spark plugs out and it looks like it is running a bit rich. I have not checked yet if the choke mechanism inside the carb is actually fully opened when the choke is turned off im gonna try taking a look at that since its not that hard to pull off. Although the problem that i have also occurs when the engine is cold and when the choke is engaged. And for the idle speed i just eyeballed what looks to be right, i have seen some posts online about screwing the idle all the way down till it just barely runs and then give it a quarter to half an turn. Also thanks for the help so far
Try reading through this thread, and adjusting the carb: https://minitrucktalk.com/threads/some-thoughts-on-carburetors.20150/
It seems that my carb doesn't have many adjustments i can make to it. i only have: choke idle adjustment, idle adjustment and a nut that decides how much fuel flows into the inlet when you hit the gas. today i also checked every vacuum hose and make sure they are on tight with clamps, although i still hear what sounds like a whistling sound from near the carb (or it could be from the air thats flowing through the carb). Today i also adjusted the carb with the distributor and it seems like its running as best as its gonna get i haven't gotten the problem where the engine stalls out randomly although when the engine is running idle it still is a bit shakey.
Clean up the extra carb, and post some pictures. It should have adjustments, but they may have covers over them, because they didn’t want us idiots messing up the emissions.
I have cleaned the carb and checked everything many times but i still only see the idle adjustment screws and the air fuel mix screw. I also noticed that the thermostat is missing in my engine, could that also be a cause of the engine running poorly since im currently out of ideas on what to do with it.
If it's anything like the 660 carb, it could be with no thermostat, the wax plug that softens as the carb warms up and releases the choke isn't melting because the water flowing through the carb remains cold? Thus, the choke stays on or partially on and the mixture is too rich to idle properly etc.
Roadster, actually as the wax pellet heats up, the wax expands and moves the piston, as it cools it contracts and moves the piston back in with it. A good explanation:
Thanks for the explanation Jigs... So the wax plug expands as it warms and contracts as it reverts back to solid, opening and closing the choke is what I gleaned from that youtube. Do you know if the water flowing through the carb would be affected by the thermostat being missing or if it might be a separate loop from the water jacket somewhere? I'm wondering if the wax motor not heating up may be the cause of Niek's running rich problem?
Thanks for the explanation but i dont think its something with the choke, since on my engine there aren't any coolant lines or hoses on the choke. My choke is operated by a cable and besides that it has some vacuum mechanisms that also automatically engage the choke but im almost certain that everything is working properly on there since the entire carb is cleaned up, vacuum lines checked multiple times and everything seems too work fine and nothing seems to get stuck while the engine is running.
Here is an exploded view of what my carburetor exactly looks like: https://www.easyparts.nl/explodedvi...0-1992-2009-(EMEA)-Carburation-m26904-d199127
Here's a small update, i've ordered this carb and put it on my truck: https://nl.aliexpress.com/item/4001...exp_id=50d346c6-f291-4442-9b12-5826782bffd4-3 It runs great now and i've taken it for a testdrive, however after like 5 minutes of run time the engine starts hesitating untill it stalls out. I think it has something to do with the fuel pump that i replaced (which produces between 3 to 5 psi of pressure) and the fact that this new carburatur doesn't have a return line (because the old one had one had a return line on the carburatur and there is an connection for a returnline on the fuel tank).
Get a fuel pressure regulator and et it down to about 2-psi. Your over-pressurizing the needle valve and flooding it out.
Im planning to get order this cheap one: https://www.bol.com/nl/nl/p/brandstofdruk-regelaar-lage-druk/9200000119354117/ It shows the pressure settings ontop and is specialized for low pressure purposes which is exactly what i want, only issue that im having is that the original fuel circuit on my truck had an return line on the carb (and the new one doesn't) and the fuel tank also has a return line connector. Do you think i can cause a problem if i get this fuel pressure regulator without a return line?
