Hi, I'm fairly new to IH8MUD and this is my first posting. I have a 1971 FJ40 with a GM Rochester carb that was on it from PO. It was a carb setup from Man-A-Fre when they were located in Agoura, CA. It ran great for several years before it sat for another several years in my garage. I'm slowly replacing things as I get it back up and running. It's been back up and running great again for a bit but the last few times when I shut it off, I noticed that gas looks like it's coming from inside the top of the carb and running down the outside. I just now replaced the fuel pump and it still does the same thing. Running really rich and fouling the spark plugs. I couldn't start it back up after this happens. Not sure what to do other than replace the whole carb. ( I actually did buy a stock carb from a cruiser place and had it rebuilt. Put it on but ran rough and sounded like a vacuum leak somewhere so I swapped back to my original Rochester). Any help/guidance is greatly appreciated.
Carburetor flooding after I turn the engine off. (1 Viewer)
- Thread starter kdog
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Skreddy
SILVER Star
Not too familiar with the Rochester but sounds like fuel is pushing past the float needle either because the float isn’t floating anymore, junk keeping it open or the tang has bent and changed the setting. Likely due for a rebuild.
I’d see what you can do about getting the stock carb working, but that’s just personal preference.
I’d see what you can do about getting the stock carb working, but that’s just personal preference.
Check float level and the float for any damage. Probably need to rebuild the carb.
- Thread starter
- #4
Thanks for the advice, I'll check it out.
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- #5
That was my intention but I couldn't get it to idle smoothly, I do want to get it working though.
Is your fuel pump mechanical or electric?
I've had electric fuel pumps overpower the float and flood the carb, which my specific engine could easily cope with but it did burn way too much fuel and ran terrible.
Wasn't a Landcruiser but the principle is the same.
A carburetor needs 2 to 5 psi, of fuel pressure. An electric pump designed for fuel injected engines can make upwards of 50 to 60 psi which will burry your float.
Otherwise clean the needle and seat, check that the float floats, and put a good fuel filter on it.
I've had electric fuel pumps overpower the float and flood the carb, which my specific engine could easily cope with but it did burn way too much fuel and ran terrible.
Wasn't a Landcruiser but the principle is the same.
A carburetor needs 2 to 5 psi, of fuel pressure. An electric pump designed for fuel injected engines can make upwards of 50 to 60 psi which will burry your float.
Otherwise clean the needle and seat, check that the float floats, and put a good fuel filter on it.
- Thread starter
- #7
It's mechanical. I also put a new fuel filter on not long ago. I'll pull the Rochester off and look at the float and check the seat. At the same time I want to see if I can get the stock carb on it. Not sure I had all the connections on it correctly though. On the Rochester, all I have is the pcv hose and dizzy vacuum advance hooked up to it. The other vacuum ports on the drivers's side are closed off.
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- #8
Another question which is off topic but I'm finding that the vacuum advance part of my dizzy is bumping up against the oil filler tube when I'm trying to do the timing. Seems that the sweet spot is probably right where the oil filler tube is. Is this fairly common or is something off? Thanks.
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If you have a rebuilt Aisin carb, why not resolve the issues with it rather than fight a non OEM carb?
As for the dizzy, a couple of pics would help. I bet it was replaced with a Delco unit by the PO when they did the Rochester carb
and installed incorrectly.
Man-a-fre was good at convincing people that OEM parts were no good.
As for the dizzy, a couple of pics would help. I bet it was replaced with a Delco unit by the PO when they did the Rochester carb
and installed incorrectly.Man-a-fre was good at convincing people that OEM parts were no good.
Skreddy
SILVER Star
As pjohnson said: pics would help. Some of your distributor and your carb(s).
71 was probably a vacuum retard distributor, not vacuum advance. If it’s retard, don’t even hook up to vacuum. If your bumping the oil tube you have 2 choices: pull distributor out and move the gear a tooth or two or move all the wires 1 spot over on the cap. But if you have a numbered cap, it won’t match.
71 was probably a vacuum retard distributor, not vacuum advance. If it’s retard, don’t even hook up to vacuum. If your bumping the oil tube you have 2 choices: pull distributor out and move the gear a tooth or two or move all the wires 1 spot over on the cap. But if you have a numbered cap, it won’t match.
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- #11
Here is the dizzy hitting the dip stick tube.
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- #12
Here is the rebuilt stock carb I was talking about. I plugged the diaphragm because from what I've been reading, I don't need it. Correct me if I'm wrong. The one tube coming out of the base on pic # 4 I have hooked up to the dizzy . The other larger tube coming from the spacer is hooked up to the PCV vacuum hose. Let me know if something seems off or weird. Thanks.
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- #13
So I swapped out carbs and cleaned the fouled plugs again. Hooked the one small vacuum tube on the carb to the vacuum from the dizzy. Also the PCV vacuum hose to the base tube on the carb spacer. Had to spray some quick start to get it going. It ran but the idle was pretty high. I'm glad it was running at least. I had to adjust the two large nuts on the throttle cable to allow the idle to come back down. Still running a little rough though. Plugs might be a little fouled so I might get a new set. These are almost now and I've tried cleaning them each time they get fouled messing with the carb. I shut it off and then could not get it to start. I need to possibly adjust the larger mixture screw on the opposite side as the small vacuum tube. Also the timing may be out just enough to keep it from starting?? I'm glad though that the stock carb seems like it will be good moving forward. BTW, I didn't know that the dizzy can be just one or two teeth off and it still run fairly decently. If i move the wires over, which direction do I move them. plug #1 on the cap move clockwise one plug?
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Skreddy
SILVER Star
It looks like the wire for the idle fuel solenoid is cut and taped off. That should go to a switched power source (like + on the coil). That may help idling.
The plug wires you can just move counter clockwise 1 position, then rotate the distributor clockwise 1/6 of a turn and go from there.
The plug wires you can just move counter clockwise 1 position, then rotate the distributor clockwise 1/6 of a turn and go from there.
Curious why you have to keep cleaning fouled plugs--Are all of them fouled?-and how are they fouled? Carbon?-oil? You don't seem to be running this engine long enough for any fouling to occur--
The idle solenoid was designed to eliminate 'run-on' after the ignition was shut off--gas engines typically don't do that when there is no spark to ignite the fuel--(diesels-yes)--I don't have an idle solenoid at all(2F engine), and have never experienced this 'run-on'.(unless maybe the engine was over-heated)
The dizzy should not be impacting the dip stick-(is it stock)? Going the route of re-seating the dizzy to a different gear notch will forever foul up any future troubleshooting without remembering which way you turned it, and the next time you need a new cap the plug numbers will be wrong--
Just as a wild thought--what if the PO did this very thing? it might account for the dizzy hitting the dipstick, AND why the engine seems to not start right away--and the fouled plugs
It might be advantageous to pull the dizzy and re-install according to the FSM-----
The idle solenoid was designed to eliminate 'run-on' after the ignition was shut off--gas engines typically don't do that when there is no spark to ignite the fuel--(diesels-yes)--I don't have an idle solenoid at all(2F engine), and have never experienced this 'run-on'.(unless maybe the engine was over-heated)
The dizzy should not be impacting the dip stick-(is it stock)? Going the route of re-seating the dizzy to a different gear notch will forever foul up any future troubleshooting without remembering which way you turned it, and the next time you need a new cap the plug numbers will be wrong--
Just as a wild thought--what if the PO did this very thing? it might account for the dizzy hitting the dipstick, AND why the engine seems to not start right away--and the fouled plugs
It might be advantageous to pull the dizzy and re-install according to the FSM-----
Skreddy
SILVER Star
The easiest thing you can try to get more room between the advance can and dipstick is move plug wires 1 spot counterclockwise, then turn distributor clockwise. The better way is to reseat the distributor with the shaft (rotor) more clockwise then it is now (this keeps the plug wires in the right spot on the cap).
I would move plug wires first for troubleshooting, then move distributor shaft once it’s operating correctly.
That distributor looks like it may be a vacuum advance and possibly a pertronix ignition.
As for the carb, loosen the nuts on the throttle cable so there’s some slack that way you know the cable isn’t interfering with settings. Start with the mixture screw (on valve cover side) 2.5 turns out from lightly seated. Back the curb idle speed screw (firewall side) off so the butterfly is completely closed, then screw in 1-1.5 turns.
The idle solenoid needs to be hooked up to a 12 volt source to function. When you activate the throttle by hand looking down carb (not running) are you getting a good full stream from the accelerator pump into the primary barrel (valve cover side barrel)?
The vacuum diaphragm off the back of the carb; you don’t need to cap the nipple, but if you do, I’d get an actual vacuum cap. Other 2 vacuum hookups are in the correct spots.
Is there fuel in the sight glass when cranking or running? Where is the level in relation to the center dot?
I would move plug wires first for troubleshooting, then move distributor shaft once it’s operating correctly.
That distributor looks like it may be a vacuum advance and possibly a pertronix ignition.
As for the carb, loosen the nuts on the throttle cable so there’s some slack that way you know the cable isn’t interfering with settings. Start with the mixture screw (on valve cover side) 2.5 turns out from lightly seated. Back the curb idle speed screw (firewall side) off so the butterfly is completely closed, then screw in 1-1.5 turns.
The idle solenoid needs to be hooked up to a 12 volt source to function. When you activate the throttle by hand looking down carb (not running) are you getting a good full stream from the accelerator pump into the primary barrel (valve cover side barrel)?
The vacuum diaphragm off the back of the carb; you don’t need to cap the nipple, but if you do, I’d get an actual vacuum cap. Other 2 vacuum hookups are in the correct spots.
Is there fuel in the sight glass when cranking or running? Where is the level in relation to the center dot?
- Thread starter
- #17
The plugs were getting fouled from the mixture being too rich on the Rochester carb. Just black, not oily and all of them equally. I'll hook up the idle solenoid and follow the 2.5 screw turns and idle screw when I get a chance. I'll also move the plugs just to troubleshoot to see if that works. I'll also check for gas in the window. Thanks for all the suggestions. I'll post what I find when I get a chance. FYI, I did set it up with the Pertronix electronic ignition.
Skreddy
SILVER Star
How are you cleaning the plugs?
I chock them in a vice, electrode side up and burn them off with a propane torch until clean, usually a minute or 2 per plug. Old timer hot rod guy showed me that. Who knows if it correct but they always come out clean!
*Dont touch them bare handed after this! They’ll be hot!*
I chock them in a vice, electrode side up and burn them off with a propane torch until clean, usually a minute or 2 per plug. Old timer hot rod guy showed me that. Who knows if it correct but they always come out clean!
*Dont touch them bare handed after this! They’ll be hot!*
- Thread starter
- #19
I'll give it a shot, thanks!
