[1452]

Howdy. Hopped in the Jeepster last night ('69, stick shift, 225) to help a friend pull a dead vehicle across their property and get some stuff moved around. I hadn't driven it in a couple weeks, and it was really cold yesterday.
When I put on a rebuilt Rochester carb last year, it was from a different model, so I couldn't hook up the automatic choke. Instead, I hooked up one of those manual cables. After cranking it for 2 minutes with nothing, I pulled the air cleaner off to see how far the choke had closed things off - apparently not much. I pushed it most of the way closed, and cranked it- engine caught, ran for a couple seconds, backfired really loudly, at which point 2' flames shot out the top of the carb. turned it off, blew out the smallish flames burning down inside the carb, reset the choke, and tried again. This time it caught, backfired with smaller flames, but then caught a smooth idle. Looked at the exhaust, and it was really smoky for about a minute or so, at which point it was then idling quite smoothly, although a little high, and not smoking.
Ok, so the question- how far should the choke be closed when starting up? Did I have it too far open or too far closed? Those flames really made me nervous. I think the problem is with the choke, because once everything is warmed up, I can cut it off, and then it starts right up with no problems. I thought I had it set right, but obviously not.
Thoughts? Tips?
Thanks,

 

[2711]

on most engines when you switch to manual choke, its guesswork- an autochoke(spring loaded) is somewhat adjustable, but will hardly ever be completely closed. You need to set it where the engine wants it-

in my experience, i leave my manual choke about an eighth 1/8 off of closed- but thats just they way it likes it when its really cold- closed never works for me...too much gas an not enough air, and anything over 1/8 is too much air.

in warm weather, i close it down to the same 1/8, but as soon as it starts to even think about fireing, i pop it to half, and let the fast idle take over.

I wouldnt worry about the flames yet- seems to me you just barely flooded it, and then it caught through and backfired up-- common enough....still scary though.

I got an older friend who has two arms with no hair and scar tissue from the waist up from a carb fire- use caution, you only got two eyes, everything else is fixable.

 

[clffhnger]

I think there is something else wrong if it's backfiring thru the carb.
maybe timing
maybe valves
maybe ignition problems (in the distributor)
maybe I don't know?
just guessing

 

[2711]

yes, no, and maybe-

if it was running fine before, and it shot flames this time, I suspect it was almost flooded- with good spark and lots of gas, it happens.

If it wasent "quite" running right when you put the new carb on last year, it could be mucho many things- but you didnt play with the timeing to do a carb job- unless the points are weak...or off....or......or....shoot-idea bag is empty.

 

[1452]

I'm thinking/hoping that it was flooded- I had been pumping the gas trying to get it to catch.
Anyway, I made an aluminum bracket at work today to try to make the manual choke more solid, and try to set it so that it's just a tiny bit open at full choke. Hopefully this will work, because they're calling for more snow tonight and tomorrow...

 

[RRich]

You had it sitting for a couple weeks -

-- Sitting the fuel was evaporated from the carb, you cranked and cranked - and pumped like crazy - but no fuel was there to pump. It takes time for the pump to suck (without prime) all the way from the tank - at first it's just pumping air, creating a negative pressure to lift the fuel. Just about the time fuel was in the carb you choked it too much and pumped even more - instantly flooding.

Always - no matter what vehicle - only pump while it's cranking - when fuel gets up it only takes one or two squirts to start it. More than that floods it.

Once it tries to start you know fuel's up, then give it some choke. If it dies, take choke off (open), one or two more pumps while cranking to fire, then choke again once it catches.

The pumps will make it fire, then use the choke to keep it going.

Through the years using a manual choke has become a lost art - we've been spoiled by automatic chokes and FI.

 

[1663]

i contemplated putting a manuel choke on my truck. instead i plan on getting the commando running. At least then ill have a vehicle i dont mind putting money into

and kudos on the choke. ive had vehicles come to the shop running so rich. it was a matter of just switching off or pushing in the choke lever

i think of it as an anti theft device. even if the damn kid could hot wire the truck, he'll flood it before he gets it to start. And by then im already kicking him to kingdom come

 

[645]

next time have marshmellows and hot dogs ready.
i think you just need to fine tune your choke usage as well, your engine is fine.

 

[RRich]

He He - funny - A friend told me about the time an old lady brought her old, but almost new super low miles '52? Chevy in to his shop. She complained it barely ran "most of the time."
He could see it had a new carb, she said it had 3 carbs put on by the dealer, new distributor, coil etc. A big stack of service records. It had been "shotgunned."
He drove it, fiddled with it - couldn't find anything wrong.

Finally he took her for a ride in it, but this time had her drive. She got in, adjusted the seat way up, sqirmed around getting comfortable, then pulled out the purse hanger and hung her purse on it.

He had to tell her the purse hanger was the choke!

---- Operator Error ------

 

[1452]

So last night I put on the bracket to anchor the cable, and set the choke so that it's about 1/8" open when in the closed position. Cranked it up with choke on, and it caught quickly and easily, a couple smallish backfires, and I had to feather the pedal for about a minute until the idle settled down, and then after that it was fine...Is that about the best I can hope for? Seems pretty good for an old engine in ~40 degree weather...
thanks again,