fuel delivery or carb issue thoughts/opinions (1 Viewer)

[77cruiser]

First, thank you for helping and sharing your thoughts. here is what i have going on with my 77fj40:

• Car starts and idles fine and drives fine under first and second gear and even into third because for the most part RPM's are up and its at or close to full throttle. Once i am not having to be at full throttle in 3rd and 4th gear its missing or seeming to not get enough gas. After driving it for about 15 mins on the road it will even cut out at stop lights. Carb was rebuilt about 4 years ago and its not driven more than about 200 miles a month so maybe the lack of driving has caused clogs or issues with the carb or debris in it?
• I have checked vaccum and lines and all seems good
• I have pulled air cleaner lid off and let it run without and choked it out with my hand over carb so i can tell vaccum is strong
• I used to be able to go about 60-70 with ease and now i have to push the pedal thru the floor to get it up to 60.
• I pull the air filter out today to clean it and it smells like gasoline and the side closest to the carb actually appears to have gas on it.
• I have an exhaust leak i am sure about but i doubt this is causing this issue. I am going to have this fixed next week.
• Fuel filter is Toyota and brand new
• I have a new fuel pump i could install but since i am getting gas i am thinking that is not the issue.

would you say that all signs point to rebuilding carb? or are there other things you would suggest

 

[FJ40Jim]

Check the ignition timing and the mechanical advance.

Check operation of the heat riser.

When it's running bad, quickly turn the key off & check fuel level in sight glass.

 

[77cruiser]

I know how to check the timing. How do you check the advance?

 

[kurtnkegger]

Take the cap off, and wiggle the plate the points are mounted. Mine had surface rust, and needed to be cleaned, and lubed to make sure it was able to get into position. The plate should rotate a little like a turntable.

 

[FJ40Jim]

To check the mechanical advance, remove cap, twist therotor in the advance direction (CW). It should move about 10 degrees against a spring, and snap back to the rest position when released.

 

[ingomar]

Aside from ignition and fuel checks, you might want to run a compression test and lash the valves. It's just part of knowing where you stand and will tell you if there is any problems inside the motor.

 

[77cruiser]

Excellent. Will test this monday after mothers day. Thanks for the help so far.

 

[Pin_Head]

Fuel delivery problems tend to make it buck and surge cut out and and spit back through the carb.

X2 on the mechanical advance. Spray some WD40 in there and work the rotor back and forth.

 

[77cruiser]

I am thinking mechanical advance. I just came back in to make sure that i had read the tips for testing it correctly because i was trying to turn it so hard clockwise i was afraid the Rotor was going to break.
Clockwise is correct way to turn it right?

 

[FJ40Jim]

Yes, CW is the advance direction. If it won't go that way, it may be already advanced and stuck at that point. Try turning it back CCW, see if it moves back to the rest position and stays put

 

[77cruiser]

Tried both ways. cant move it at all. I took a couple pics to make sure i have given you all relevant info. In the little hole in the plate i can see that it appears to have a little rust inside. dont know if thats part of the issue or not.
The last pic is the vaccumm hoses i checked and all seem to be leak free.

Thoughts?

 

[kurtnkegger]

Under that plate, is a ring of bearings, you will need to pull out the set screw that holds the advancer diaphram first, then remove the circlip that holds the connector from the diaphram to the points plate, then rotate the diaphram 90 degrees to facilitate removing it.

Then you will remove the two screws at the 12o'clock and 6o'clock positions, the plate will come off. Clean up everything, and you can get it to free up!

 

[77cruiser]

bump for thoughts?

 

[FJ40Jim]

Apply vacuum to the advance canister, see if it holds vacuum or moves the plate.

If the advancer leaks, then stop. Dissy is bad, service parts are discontinued. Get new/used dissy w/ good vac advancer.

If advancer is good, but plate doesn't move, then distributor needs completely overhauled to free up stuck vac advance plate and stuck mechanical advance.

 

[madinal]

Check inside the rotor cap for carbon arcing. It may be in the infant stages and only arc at high RPM. If that's the case, you would be runnig a cylinder or two down and not get the power to run at high speed.