carburator issue I think

havoline

Well-known member
Hey you all. Its been a while since I have been on here. Car got a new paint job and abit of body work done to it since I was overseas which was nice of my family. But before I went I installed the pertronix ignitor in my car which jumped my cars efficiency from 19 to 21 mpg in the city when I drive carefully, 24 to 26 mpg on the highway, and started the car with so much easy I dont know why I waited so long to do it. That being said, when I got back I noticed something different. The car wasnt neccessarily sitting for 5 months it was started regularly and driven a tiny bit in that time. But nothing was done to the engine. And there is something else that I think is really wrong with it: I no longer get 26 mpg I get 21-22 mpg if I am lucky on the highway, smells gas when I push the gas pedal abit to accelerate and when I take my foot off the base I smell it I think just as much. I have a vacuum gage on the car and it tells me the engine is doing really well but is on average 1 mmHG lower on everything it used to be at about 16 when going 63 mph not its 15 under same circumstances. Also I cannot in no way get the idle to get less than 1100 rpm unless I really turn down the idle mixture then it just gets really rough. (I used to have my idle set at 850rpm and the car really liked that at neutral.) The idle speed screw is almost screwed off and doesnt change a thing I can only increase from 1100+ at idle and when I am driving at 50 mph I have to put it in neutral cause its easier to stop it and the idle goes to almost 1350 rpm used to go to 1050 rpm before.

But when I drive just as carefully around town I get 21 mpg the same as I get on the highway. (Its runs smooth, starts ok, good economy in town not highway, might be timing but dont really know unless I borrow a timing light where should I have the timing at for best results towards ecomony and reliability?)

When I get this issue dealt with next is to replace front drums with disks and after that finally to get FSPP headers and after that I think I will be happy for a long time with my car towards stopping, sounding, and running good and responsibly.

(Got myself a yamaha vstar that gets 80 mpg how nice and responsible is that huh)
 
First thing would check is the float level, as well as it's drop (to low and can stick), and if it moves easy on the hinge pin, may have gumed up from the setting. :hmmm:
 
How long has it been back to regular driving? Have you been through a full tank of gas? 5 months could be old enough to have minor issues in the gas. Im personally not a fan of starting an engine and not taking it out for a good drive. That could also cause issues. Both of those should be solved by getting some regular use again.
 
I think your timing is off. The few times I've had problems getting the idle to normal levels, it's been related to the timing being way off, causing the carb to vacuum advance the dizzy too much causing the rpms to stay high. It a circular problem which both have to be adjusted. Double check all your vacuum connections for leaks or anything that may be been misplaced.

I've never had those problems caused by gas sitting for long periods. The gas I have in my tank now is probably 9-10 months old since the car last ran. I was able to fire it right up and get it retuned as soon as I charged the battery. While it is possible you have a partially clogged fuel filter, it is highly unlikely to cause the high idle RPMs. Do check the choke circuit on the carb. Make sure the choke is operating properly and opening fulling when the car is warm.
 
havoline":9hppmjhm said:
I have a vacuum gage on the car and it tells me the engine is doing really well but is on average 1 mmHG lower on everything

Vacuum Leak. Ruber hoses get old, crack and leak. Check/replace every one in the Vacuum circuet including the one on the Auto Trans if you have one and in the interior of the car if there are any.
 
I think Auto is 12* BTDC. With your mods, 12* is probably a good starting point for good mileage. I'm at 10* with my T5.

If the timing checks out (if you don't know the age of your timing chain, verify TDC damper mark just incase), I think you have a vacuum issue somewhere.
 
just what i've noticed... not saying it's a/your problem... gas can turn to varnish over time, and varnish is horrible for engines, even deadly. confirm your not running varnish. (i'm in AZ so i guess we use the same gas types (like summer mix vs winter mix that the gas stations control))
I noticed pertonix and 8mm accel wires, meaning you probably don't have the 1100 and LOM dis, what setup do you have, maybe some can shed some light with thier experience.
Maybe Air Presure in your tires???
all fluids are up? oil/tranny
Confirm you don't have a vacum leak... check everything that carries air.

other than that, maybe she just really needs to be loved again every day???
 
69.5MAV is probably right.Vacuum leak big time.Replace ALL vacuum lines where ever you
find them.That should fix things A-OK.Also,check the vacuum fittings also,one could have cracked.
Leo
 
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