I bought an S81 Jumbo that has not ran in a few years. When I prime it, it will run. Are these carburetors know to stick floats, etc? What actuates the fuel cut off solenoid? A safety switch maybe? How finiky is the choke mechanism? I have the FSM but dang, a quadrajet looks easier to work on. Getting to the carb is a big enough task for a full size human.
check your fuel filter and fuel pressure first. it is likely that the carb is gummed up and the fload is stuck, but it's easier to get to the fuel filter first and check the fuel pressure. the fuel cut-off solenoid may be stuck as well. unscrew it from the carb, ground it, and turn on the key to see if it actuates. it should be sticking out and retract when energized. if it isn't retracting, then take a pair of dykes and cut the plunger off... worse thing that will happen is that i might run on a bit when you turn off the key, but it will get you running.
Hey dan Its not as bad as you think to get it off . I can get it off in under 10 mins Ive had mine off a couple of times and they are way easier the a smogged fj 40 or 60 . Once it off you can pull it all apart and clean it . Its most likely just gummed up .
Did I forget to mention it was a Jumbo? Take the access panel out of the bed is way easier to get to that side of the carburetor.
Anybody have any idea what size Allen wrench the bottom bolt is? I swear I'm gonna thow 5 gallons of diesel in the POS and then throw a road flair in it.
D'Animal, Don't let that lil' truk whip ya. Don't have a clue what size allen bolt is on the carb. Just make sure you got the mm size vs inch size (whatever that size is). Also, you prob would only need a quart of gas and a match ........later, slim
Its a 6MM , I used a socket type on it as it really a nut with that allen key added on for making it easy to get off
I think the PO stripped it or buggered it up. The 6mm won't go in and the 5.5 spins in hole. A 3/16 is close but still does not work. I take another stab at it. I know who is going to win this battle.
What the thing is ,is a extension that fits on a nut . just tap the 6mm on and break it loose When you get it off you'll be "WTF thats all it is ? " The only way I figured out what it looked like was by looking at the Parts catalog until I got it off . Its actually a pretty neat design
So I got the bugger off. I had no fuel in it but did have some dust in the bowl. Is the slow solenoid the one I can just cut off? It is the one with one wire going to it.
before you cutting anything off what I was able to do was get them to loosen up with some carb cleaner and other things . Let them soak a while then toss 12v on and off to loosen up . Ive had great luck doing this with my TLC 40s and 60s plus this little bugger . These are fairly easy carbs to work on (and alot bigger the a chainsaw one ) just shoot cleaner all through it . If you look under the fuel system ref PDF for the highjet (in the this forum) in it shows your carb and what does what . good luck op:
I have the FSM as well as the parts break down. I disassembled it and cleaned it and reassembled it. I have to set the choke correctly and then put it back on. I thought I could cut the tip off of the "Slow" solenoid to get away from the 25mph speed governor.
does it have the D/N lever (transfer case ?) If so you can just pull the "C" clip out so it shifts into High as thats all I did . Im able to cruise much faster then 45 without messing with the carb .
See this thread for more info ---->>> http://www.minitrucktalk.com/showthread.php?t=1318&page=2 on the "C" clip they are refering to. op:
nope, you just pull the PTO cover and I used a mirror and a good hook pick with a magnet on it to keep the clip from taking off I worked from under the truck as the Jumbos are harder to see whats going on with the little cover in the bed from the top. I had my wife move the lever from D to N to see where the movement and where the shift fork hit when pulled past the N stop . When it removed you can pull the lever past the N and into the high position and off you go to really take off
So how often do the fuel pump go out of these rigs? Before I put the carb back on I tried to start it. No fuel is coming from the pump. Filter is clear and no blockages in the line to the pump.
Complete cleaning of the fuel system and got it fired up. The fluid in the tank would not ignite. After rebuilding the carburetor and double checking the fuel pump and flushing the lines, I drained the tank and put fresh in and fired it up.
After running a few gallons of fuel through it, I have a few questions. Question #1 When I start it, it literally runs WOT for about 4 minutes and then idles down. I cannot find anything in the service manual regarding properly setting the hot water activated choke. Question #2 When running down the road, it surges at 12mph. It does this in both high and low range. It act likes the fuel cut off solenoid or speed governor is activating and then deactivation. Thanks in advance. Dan
I was waiting for one of the Hijet experts jump in and answer. Maybe Dan might have a idea. He is pretty knowledgeable on the Mitsi's and some of that might cross over to the Hijet. I don't have anything to offer you on the subject - I haven't had to play with a carb yet as mine is EFI'd.
Hello Dan you still have the cut off solenoid cutting you off . I just pulled the "O" ring off that one (more like lost it ) . The other thing is you can wire it hot when the ignition is on and thats that (easier too).
The 12mph was solved by flipping the switch under the dash. Now it does it at 25mph. That is fine since the 23" Bear Claws don't handle very well above 25mph. They are loud. Any idea on the fast idle at start up? Is that normal?
D' Animal, I just bought a S81LP, USA marketed truck,4x4,dump bed. This truck is ^&%$#% to start. I have to pump the gas pedal to keep it running. When it gets to operating temp. it idles and runs fine. I think I have a stuck "slow fuel cut solenoid" problem. If I let the truck cool off same thing happens. Pump it to keep it running, gets to oper. temp. and its fine. It does idle fast till it gets a little passed half way on temp. gauge then slowly idles down. Where is that switch under dash for 25 mph? I am thinking the "main fuel cut solenoid" is ok because it runs fine at oper. temp.
Reach under the glovebox for tyhe switch. There is a black box with a wire cluster pluged into it. There is a little slider switch to the right of the wire cluster. I think if the switch is to the left, it is for 12mph and if it is to the righ it is 25mph. As for you running, sounds like you may have a hole in you fule line and it may be by passing air through the pump. Your choke could also be out of adjustment.
I looked at fuel lines from tank to inlet @ pump. Hose looks good all the way. I can crack the inlet @ carb. and its getting plenty of fuel while turning over. I am going to remove slow fuel cut solenoid today and test it. See where that leads to. When you turn on your ignition can you here or feel your slow fuel cut solenoid shift? Anybody else want to chime in feel free.
trax, i would look into the choke. that's probably the problem. if set incorrectly it will certainly be hard to start (lack of air) and run a high idle (high idle screw set too far in to compensate for the choke being set closed too far) until it kicks off when it reached operating temperature. JMHO
