The Stovebolt Site Forums The Shop Area Engine Shop Persistent choke problem

Hi All,

In a well worn earlier post I told of my 216 engine not running nor idling without the choke being almost all the way out.After many good tips and no results here is my update. I removed the manifold and found the gasket that separates the two halves had a sizable chunk gone out of it common to the side near the engine block where it could not be seen. I removed the manifold and replaced it with another good one from another engine. With new gaskets and rings I reattached it,installed the carburetor and with all vacuum lines blocked( hydrovac,two speed etc...)fired it up only to discover THE SAME PROBLEM !Guys I am real close to a gallon of gas and a match or the scrap yard cause this thing refuses to run.Any ideas would be appreciated cause I am fresh out.

Thanks,
JMH

Did you check the manifold for being straight. I always put manifolds on a belt sander before I install them. A chunk out of the manifold where it joins the exhaust would create an exhaust leak, not a vacuum leak. Have you tried a different carb. It may be junk in your metering jet. I have sometimes got carbs to straighten out by revving up the engine and then putting my hand over the carb. It creates a heck of a vacuum and sometimes sucks stuff on through. Don't even think of torching it yet.

remove the choke and see what happens..
my 235 did not have one and it did great, pat the foot feed twice,hit the floor starter and she would be purring like a kitten

JMH, Sorry you're still having trouble--she's give you a helluva time but look at the things you've learned through the battle.
Sounds like you've worked on the gasketed areas a bunch and are satisfied with their sealing ability.One way I have found leaks at the gasketed areas is to flood them with a water hose with the engine running.I know everybody wants to use carb cleaner or starting fluid but I'll try water flooding first if it's convenient.You can hear a difference if a leak is flooded.
Also consider valve guide condition.Not from a wear standpoint-that doesn't give your massive leak but I once had an engine totally destroy and pass a guide and it so affected the cylinder it shared a port with that we couldn't get that cylinder to hit either.Vacuum leak bigtime.
Maybe an inspection of inlet guides from above with some oil squirted around them might prove that's not a problem.
It just still sounds like that carb has a circuit blocked.
Please keep us posted.

Have you done all the routine tuneup stuff, like compression test, valve adjustment, dwell & timing, etc.?

It might be good to do a cylinder leakdown test, where the truck is locked into high gear with the parking brake set as each cylinder comes up on top dead center on the compression stroke, and air pressure is put into the cylinder through the spark plug hole. Listen for leaky valves at the carburetor and tailpipe, and bad rings by listening at the crankcase oil fill hole.
Jerry

if the engine only runs with the choke almost fully on....

maybe the carb float is out of adjustment or it's running too lean.

does the dist. vacuum pot work, not working is a nother source of a vacuum leak...try disconnecting all external vacuum line and plug them to see if it runs better....

I'm not familiar with the old post but if you have not gone into the carb that would be the next thing to do.

To "Enginenut"

You gave reference to a blocked carburetor passage. When I rebuilt the carb. I replaced everything that came with the kit. Two springs,balls,accelerator pump and a gasket. It is a Rochester "B" carb. I bought a gallon of cleaner and after a good soak I reassembled it. Set the float per spec. etc... Are there any "plugs,knockouts" or secret passages I could have missed? I tinkered with it today and you can open the choke and it will crank but after a about ten seconds it shuts down or if you are quick enough you can pull the choke and keep it running. I looked in the service manual and cannot find anything that I think I may have missed.

Thanks,
JMH

I messed with my mod. B for a long time rebuilt it twice and it still ran like c*** I was talking to a fellow bolter about it and He said He had done the same ,He dumped the "B" and rebuilt a carter W1 so I bought two W1s that were on Parts for Sale rebuilt one and kepted the other for spare parts,now the 216 runs like a top no more keeping the choke pulled out, no hesatation just a good pull of power from frist to 55 MPH.I just took My 52 to Kansas city 1030 miles, no I mean No problems at all.My advice is dump that "B" and get a W1 on her ,I pump the pedal once and hit the foot starter and she just sets there and runs.

Pete

Pete52

Just so happens I did try a Carter off another engine and it behaved the same way. It has not been rebuilt but from your response it could be! I'm up for any and all suggestions. Thanks for your response.

JMH

Just looking at a cutaway of the "B" and see the joint of the jet well joining the carb upper body above the fuel level.A minute leak there would weaken the vanturi vacuum lifting fuel to the main discharge nozzle and this passage also supplies idle fuel.
I would take a close look at this area and passages from main jet to discharge nozzle.
Use a small hose to direct cigarette smoke into these passages looking for blockage or leaks.
PS don't inhale they say it's harmful to your health.

You did the job halfway. The carb cleaner softens the deposits, but the passages must be cleared with massive volumes of air. I use very hot, almost boiling water to flush and clean everything after the soak in the carb cleaner, then I use a needle-point nozzle on an air gun to blast high-pressure air through every passageway in the carb. One carburetion instructor at the General Motors Training Center in Memphis, Tennessee used to say "Put 55 gallons of air through every hole!" That was his way of saying there's no way to overdo it when blowing passages clean. Simply soaking, then reassembling will just let the deposits harden again.
Jerry

I have blown a hurricanes worth of air through it and still no luck.Think I will junk it and go with a Langdons 2 barrel adapter and Holley carb. For around 100.00 I can get the whole shebang.What have I got to lose but more money.I have tried most everything else.

JMH