4 barrel roch. carb question

[cutlassguy]

the temp gauge has 40-100-140. like i say it used to run right at 100 but since i changed the thermostat, now it running in the middle of 40 and 100. im not sure what the heat range of the plugs would be bill, i just bought the ones the book at CT said were for my motor. ive always had good luck with acdelco's so im thinking tomorrow ill go an grab a set and try them out. any recommondations on a better plug for a 305? i triied MJK, Champion, ACdelco, bosch, and copper plus and so far the best seems to be the AC's. i checked and rechecked all my vac lines and hoses while it was running, triied wiggling them to see if there was a crack that i never noticed before but nothing, i replaced most of them when i got the car so they're all in pretty good shape. whats the best way to tell if i have a vac leak? i hooked up my vac gauge and it was in the normal range at about 19 inches. unless its a intake leak, i cant see or hear anything that would lead me to believe that. it also idles really smooth too, just when i give it gas it bogs out until i tromp it a bit. anyone know if i can adjust my rocker arms? or would an 87 305 have roller rockers. im going to try and borrow a compression tester and see what the cylynders are at, the plugs seem to be burning pretty clean tho so i dont think its a head jasket or anything like that...i dunno already

 

[cutlassguy]

actually where its sitting in the pic is where it sits now fully warm.

 

[techg8]

first thing I would check is the accellerator pump function. look in the primary bores and actuate the throttle arm. look for two streams of fuel. If they dont shoot into the primary bores when you move the throttle then you have a bad pump or clogged passage.

 

[bill]

vacuum gauge testing is a great diagnosis tool and would indicate a vacuum leak, bad valve, poor timing, etc...
I would also agree that it sounds like a carb problem. I suggest a rebuild of the carb...ethanol can fubar an old carb.

This is a good link for the vacuum diagnosis
http://www.secondchancegarage.com/public/186.cfm

Try to find a good carb rebuilder and they usually dont charge a lot. There are usually a few shops that have a carb guru who does it on the side. Just gotta ask around or go to your local parts store and ask about it...they usually know of somebody who rebuilds em. As for the plugs, Id stick with the AC's and use the recommended plugs for the yr/engine/etc.

 

[cutlassguy]

yep thats one of the first things i checked and theres 2 GOOD streams of gas coming out. after pissing around with it some more today im almost sure it has something to do with the choke cause the only thing i did that made any difference was when i stuffed the kleenex in there and closed the choke a bit. from everything i read 19 inches of vacuum is pretty good for this motor so i cant see it being a leak, also anytime ive had a vac leak it always idles like sh*t and this is silky smooth. i blocked a little over half the rad tonight an went for a cruise to see if i could raise the temp a bit and see if it made a difference but even with the cardboard there it never raised anymore so tomorrow im also going to chuck the old thermostat in there and see if i can get it running around 100 again. is it possible for the mixture screws to just up an go to sh*t out of the blue? i never touched them but im wondering if they might need adjusting. also does that adjustment have alot to do with acceleration or is it just for idleing. same question for the choke pull off....how could anything in there possibly change on its own? isnt it just linkages and a little vac diaphram??

 

[cutlassguy]

thats an awsome link bill thanx!!! im going to hook it up again tomorrow and see exactly what it does. hopefully it'll give me a better idea as to where to look. mind you the other day i hooked it up and it was at 19 and never budged so who knows...either way those senerio's are a GOOD thing to know in my books! just out of curiosity, when checking fuel pressure would you connect it to the intake port of the pump? anything past that and id imagine it would squirt gas into the gauge...lol

 

[cutlassguy]

checked the vac again at the brake booster line and it was 19 but would slightly far about 2 inches and then regain it again. according to that senerios thing it improperly adjusted mixture screws but again why would they be fine one minute then all of a sudden go to sh*t?

 

[cutlassguy]

well the latest is i switched the thermostat from the 180 i had in there to the 195 that was in there before and now its running just a little below 100 but now its actually half-*ss drivable. theres still the chug just after you hit the peddle but once your about quarter pedal down it accelerates pretty smooth. picked up a fuel filter so im gonna throw that in and see if theres any difference. tomorrow will be the new acdelco plugs annddd we'll see whats up after that. thanx for stickin around guys, sometimes bouncing ideas off of eachother gives me new ideas of what to try. much appreciated!!

 

[cutlassguy]

heres a link to what exactly the vacuum gauge is doing. is there something anyone else see's that i should be concerned about?

 

[cutlassguy]

http://www.youtube.com/watch?v=TDNd_YwX ... BVqMjHGE0=