Please feed me some ideas, here is the synopsys:
76-40, 2F, Aisan carb.
1. Vehicle was running durably, no major running concerns.
2. Then a problem started: Carb started flooding - (fuel bowl filled to max right up the sight glass and over the top, then she was dumping raw fuel under pressure into throttle body- resulting in a wet flood stall. would not idle and would not restart till she dried out a bit , and then within a moment the same thing would happen Assumed stuck float or bad needle valve - also decided it was a good time to do a full carb clean and rebuild.
3 rebuilt carb fully. - used all appropriate parts from carb kit
4. reinstalled carb.
5. She started right up, perfect fuel level in the bowl now. Nice shiny carb.
6. Gave a "tune-up" By setting the following items:
8. Headed out for a test drive, running fantastic, lots of power, no missing, Checked for engine knock as I wanted to make sure having the BB that advanced was not too far. To do this I drove at 20mph and mashed the gas - no knocking or pinging Just solid torque and no lugging. I drove 25 miles at different speeds and conditions all gears - Running great.
9 NOW THE PROBLEM STARTS
10. I was at a stop sign, and I decided I would "launch" fairly hard, I had done similar just moments before with no issues.
11. it was not an abusive start, but after hitting second, I did go to full gas pedal - On pedal application into 2nd gear, She started going totally flat like it was either flooding out or starving out - and all power was lost. So I clutched, braked and lifted my foot off the gas. came to a stop and she was idiling perfectly.
12. Tried to go again and immedialy on gas she stumbled and stalled. - quick restart, idles perfectly.
13. tried simple gas pedal wlile stopped - she would barly run on any minor push of the throttle, and if you held the pedal there, she would try to rev for an instant, and then would stall - a hard throttle push would get the RPMs up and she would stay running, but it was hard to get past the "dead zone" and even when you did, you could kinda tell something was not right. and if you dropped into the dead zone she would stall - unless you released the pedal and let her go back to idle.
14. Left her idilng, and got out to inspect things, every thing looked fine, fuel level on the mark in the window was spot on. I Hand applied throttle, same symptoms and stalling, The carb seemed noisier than I recall ( air flow & fuel noise - the wooshing sound) It really seems that there is too much fuel dumping in, I can see it and it looks like a lot
15. for some strange reason I flipped the choke closed and instead of stalling as she normally would ( when warm) she kept idling -although much rougher. I hand actuated the throttle, and although she acted "choked", it did not stall.
16. Back in the cab - with the choke still set. I found that I could drive now - although not smooth, and basically to a max speed of 25 Mph in 4th ( i did not want to push her hard) Any time I pushed in the choke - she would die (or try to).
17. I got her slowly home - about 12 miles.
Summary
She was running fine one moment, and then poof something?? happened. I am not sure where to start, and I dont want go all psycho on it.
76-40, 2F, Aisan carb.
1. Vehicle was running durably, no major running concerns.
2. Then a problem started: Carb started flooding - (fuel bowl filled to max right up the sight glass and over the top, then she was dumping raw fuel under pressure into throttle body- resulting in a wet flood stall. would not idle and would not restart till she dried out a bit , and then within a moment the same thing would happen Assumed stuck float or bad needle valve - also decided it was a good time to do a full carb clean and rebuild.
3 rebuilt carb fully. - used all appropriate parts from carb kit
4. reinstalled carb.
5. She started right up, perfect fuel level in the bowl now. Nice shiny carb.
6. Gave a "tune-up" By setting the following items:
Set mixture ( lean idle drop method )
Set Idle
Set high Idle
Set timing (Set to BB near bottom of window)
then reset them all a second time for good measure
Fresh plugs and points were put in 3 months ago
7. Now running really nice in the shop, she was idling super smooth, Vacuum was at 16in ( I am at 6500 feet)Set Idle
Set high Idle
Set timing (Set to BB near bottom of window)
then reset them all a second time for good measure
Fresh plugs and points were put in 3 months ago
8. Headed out for a test drive, running fantastic, lots of power, no missing, Checked for engine knock as I wanted to make sure having the BB that advanced was not too far. To do this I drove at 20mph and mashed the gas - no knocking or pinging Just solid torque and no lugging. I drove 25 miles at different speeds and conditions all gears - Running great.
9 NOW THE PROBLEM STARTS
10. I was at a stop sign, and I decided I would "launch" fairly hard, I had done similar just moments before with no issues.
11. it was not an abusive start, but after hitting second, I did go to full gas pedal - On pedal application into 2nd gear, She started going totally flat like it was either flooding out or starving out - and all power was lost. So I clutched, braked and lifted my foot off the gas. came to a stop and she was idiling perfectly.
12. Tried to go again and immedialy on gas she stumbled and stalled. - quick restart, idles perfectly.
13. tried simple gas pedal wlile stopped - she would barly run on any minor push of the throttle, and if you held the pedal there, she would try to rev for an instant, and then would stall - a hard throttle push would get the RPMs up and she would stay running, but it was hard to get past the "dead zone" and even when you did, you could kinda tell something was not right. and if you dropped into the dead zone she would stall - unless you released the pedal and let her go back to idle.
14. Left her idilng, and got out to inspect things, every thing looked fine, fuel level on the mark in the window was spot on. I Hand applied throttle, same symptoms and stalling, The carb seemed noisier than I recall ( air flow & fuel noise - the wooshing sound) It really seems that there is too much fuel dumping in, I can see it and it looks like a lot
15. for some strange reason I flipped the choke closed and instead of stalling as she normally would ( when warm) she kept idling -although much rougher. I hand actuated the throttle, and although she acted "choked", it did not stall.
16. Back in the cab - with the choke still set. I found that I could drive now - although not smooth, and basically to a max speed of 25 Mph in 4th ( i did not want to push her hard) Any time I pushed in the choke - she would die (or try to).
17. I got her slowly home - about 12 miles.
Summary
She was running fine one moment, and then poof something?? happened. I am not sure where to start, and I dont want go all psycho on it.
- I will recheck vacuum level, have not done it yet.
- I will check for vacuum leaks with propane and or water spray bottle.
- I will check the timing
- Is it possible that something is wrong internal to the carb?? like a spring failed or a BB got stuck ??
- How do I tell?
- My gut is telling me that its too much fuel being drawn in, and possibly with the choke set it drops the airflow down enough that it is drawing (sucking) less gas. kinda convoluted as usually the choke makes things richer, but in this case I am wondering if it is actually leaning it out enough to run.