Hi, I've got an 82 150 with a slant 6 that I bought a few months ago. Finally got her back on the road but I'm running into a problem. The engine stalls out if I put in gear before the engine fully warms up, which takes about 15 minuets.
I don't know allot about carbureted engines but based on my limited knowledge I think the choke isn't working properly. I looked around and there appears to be a rod that runs to the top of the engine from the carburetor which I think runs the manual choke. That rod is bent up some and the mechanism it goes into on the manifold looks pretty beat up and rusty.
My question is how do I check the function of the choke and if I replace it is there a more reliable electric version I should but in or should I replace the mechanical one. Given the age of the engine and therefore the age of the carburetor should I just replace the factory carburetor with something more reliable? If so what kind of money am I looking at in that case?
Thank you everyone for your help!
Megunticook
03-09-2009, 10:10 AM
Can you post a picture? I'm having a hard time picturing your setup.
I used to have a slant six, now I have a 318. Both came with manual chokes, with a very simple cable attached to a pull knob in the cab. To me this is ideal, because you can set it just how you want it (and besides, nobody else can "borrow" or steal the truck because nobody these days knows how to work a manual choke). You could set this up for under $20, depending on what sort of carb you have.
The other option is to get a thermostatically controlled automatic choke--not sure if you can buy this separate or if you need to get a carb...if you went to a carburetor shop I'm sure they could set you up.
Now would actually be a really good time to pull the carb and give it thorough cleaning and inspection, though...not hard to do (but you have to be meticulous) or else you can give it to a pro (and not just any mechanic..someone who knows carbs!).
matthew900
03-09-2009, 10:54 AM
Thanks for the suggestion on the manual choke. The last time I saw one of those on a car I was a toddler. But all kidding aside my wife can barely operate a washer and dryer so I think a manual choke will be pushing it. Are there any online sites that sell stuff like the electric choke upgrade you mentioned for after market applications on these engines? I don't mind putting some money into the engine if it'll run more reliably.
On the same subject how much is a decently after market carburetor? I'm wondering if by the time I fix the choke and have a shop service the carburetor I might be getting close to the cost of just replacing it with a new aftermarket one. Thanks!
fins2fuselage
03-09-2009, 01:36 PM
Thanks for the suggestion on the manual choke. The last time I saw one of those on a car I was a toddler. But all kidding aside my wife can barely operate a washer and dryer so I think a manual choke will be pushing it. Are there any online sites that sell stuff like the electric choke upgrade you mentioned for after market applications on these engines? I don't mind putting some money into the engine if it'll run more reliably.
On the same subject how much is a decently after market carburetor? I'm wondering if by the time I fix the choke and have a shop service the carburetor I might be getting close to the cost of just replacing it with a new aftermarket one. Thanks!
Matthew,
It sounds to me as though you already have an automatic choke set-up. The rod you describe is a linkage which runs from a thermostatic coil in the manifold to the choke lever on the carb. As the spring warms up from exhaust heat, the linkage pulls the choke blade open.
You first need to find a replacement for this (it may have to be sourced NOS on e-Bay rather than from your local auto parts store) and then we can work from there to figure out if there is anything which is preventing the system from working.
One more thing: I would also try to locate a vacuum choke pull-off (a diaphragm assembly which attaches to the carb's air horn with two screws). It is usually bad unless it has been replaced somewhere along the line.
Jeff
acton mike
03-09-2009, 06:39 PM
a couple of things come to mind
How easy is it to start the truck when it is cold? If it starts easily then it is a pretty good bet that the choke is setting properly but then the idea is to see how the choke behaves as the engine warms up
Pull the air cleaner off when the engine is cold and the choke butterfly should be wide open
operate the throttle linkage as if you were pushing the accelerator pedal to the floor and the choke butterfly should snap closed
Then, when the engine starts to run, the choke pull-off mechanism should open the choke plate slightly so that the engine can breathe and it will run on a fast idle
as the engine warms and the thermostatic spring and linkage to their job, the choke butterfly will gradually but surely open until the choke butterfly is completely open
bherder
03-10-2009, 01:35 AM
What Jeff and Mike said ... ;) Good info...
Megunticook
03-10-2009, 05:17 AM
my wife can barely operate a washer and dryer so I think a manual choke will be pushing it.
You mean she drives the truck? Holy cow, my wife won't even go within ten feet of mine. She despises it.
Actually, back in '98, before we were married, we took a 3-hour roadtrip in the truck together (hard to imagine now, she'd never agree to that these days). About halfway through, I decided she ought to drive just in case she ever had to someday, she'd know she could do it. Don't think she'd ever driven anything bigger than a Honda Civic before, and we were on narrow two-lane roads in rural Maine, including an ancient suspension bridge with 10-foot travel lanes and no shoulder whatsoever. She was a nervous wreck, afraid she was going to hit every car we passed! I think I took the wheel again after 30 minutes or so...
3834B
03-10-2009, 08:36 AM
I'm wondering if he isn't experiencing some carburetor icing as well. On the air cleaner housing air horn see if there is a vacuum operated valve and a hose running from the exhaust manifold up to this valve. It is basically a diverter valve.
This valve allows warm air from the exhaust manifold to enter the engine via the carburetor to aid in warm up and prevent icing. Icing occurs when the air temperature is cool (anywhere from from 40 degrees F and down). It's especially bad if there is any kind of humidity in the air.
When the moist, cool incoming air passes through the carburetor venturi it rapidly cools due to a pressure drop. Any moisture in that air immediately starts to form ice. This will make the engine run like crap. After a period of time heat from the intake manifold will melt the ice and off you go.
Not sure if your vehicle has this set up but it would have to have something to prevent icing. Someone can chime in if I am off here.
matthew900
03-10-2009, 09:37 AM
Thanks for the suggestions everyone. I pulled the air cleaner off the carburetor last night and discovered that a significant amount of jerry rigging has gone on with the carburetor. For starters the Choke Thermostat (ie the spring assembly that controls the choke) was in bad shape and looked like it had been rigged up from parts for another car. I plan to order a correct one and see if it fixes the problem.
I notice a number of comments about problems with the vacuum system contributing to the problem. What is a good way to test the vacuum system for the entire engine. I figured if I was going to check the lines to the carburetor I should check everything. Is there a standard name for this tool and is it something I can pick up at the auto parts store?
On my wife driving the truck this is actually the first truck that is totally mine. She had an 86 f250 4x4 with a 460 v8 in it when we got married. That thing was way more of a beast then this truck. I never had to mess with the engine on it but when the kid came she had to get rid of it and buy something she could get in and out of easily. It was pretty funny watching a 5 foot, 6 month pregnant women climb in and out of that big tall truck. To be honest I don’t miss the 7 miles to a gallon. I’m looking forward to the better gas mileage on the slant 6.
Thank you everyone for all the help!
Megunticook
03-10-2009, 09:43 AM
Good suggestion 3834B, I've had icing issues in the past during 40-degree drizzle/rain/fog and so I recently restored the system you describe on my truck (bought a new "heat stove" to bolt over the exhaust manifold from the Dodge dealer, believe it or not, mine was gone when I bought the truck).
However, I suspect matthew900 would be experiencing some rough idling and stalling if this was the problem...from what I gather the motor runs fine at idle, just stalls when he puts it in gear. Which is exactly how it would behave if the choke was wide open when the engine is still cold.
3834B
03-10-2009, 10:04 AM
believe it or not, mine was gone when I bought the truck).
Would believe it in a minute. Allot of people thought that set up was some kind of crazy uneeded emmissions system. It makes a world of difference when it is there and working.
Megunticook
03-10-2009, 10:12 AM
What is a good way to test the vacuum system for the entire engine. I believe you can get a vacuum gauge that fits somewhere in the intake manifold...
If you just want to check for leaky hoses or carb flange, take a folded rag in the flat palm of your hand and hold it over the carb. air horn momentarily. If the idle smooths out, you probably have a leak somewhere (and then you can find it by process of elimination, squeezing each hose in turn, or failing that, squirting a little oil around the base of the carb to if that temporarily stops the leak).
Megunticook
03-10-2009, 10:14 AM
Would believe it in a minute. Allot of people thought that set up was some kind of crazy uneeded emmissions system. It makes a world of difference when it is there and working.
I had absolutely no idea what it was until I read about it in the factory service manual...I used to wonder why my motor would sometimes stumble on cold rainy days--drove me nuts sometimes.
old rat
03-11-2009, 02:51 AM
Buy 20 feet of new vac line. it's cheap. Look at the diagram on the hood and replace every line as showm. Big insurance that it is all good and hooked up right. If you can find 2 barrel carb and intake from a Duper Six vehicle it willincrease power and mileage. I got my carb and intake off an 84 in junk yard for $50.00. Search forum for Super Six and Slant six/225 discussions. Wouldn't trade mine for an 8.
old rat
03-11-2009, 02:53 AM
That choke thermostat is almost impossible to find. Go with a cable choke form auto parts store but first look to see if it moves as it warms up.
old rat
03-11-2009, 11:20 AM
I'm going to my favorite junk yard in the next week or so. They have several /6 trucks. They are very reasonable. Be glad to look for anything you might need.
matthew900
03-11-2009, 04:01 PM
Hi, thanks for all the help on this ya'll. I decided to take a look at the manual last night to identify my carburetor since I found the choke thermostat on Autozone’s website and I was surprised to find that mine does not exactly match any of the ones listed in the book. It’s close to the holly 1 barrel carburetor but still different enough to make me concerned. Here are some pics I took:
Since everything is so rigged up I figured that maybe the carburetor and even the engine may have come out of something else. Let me know what you all think. I particularly enjoyed the extension that was welded onto the Choke Thermostat so that it would reach the carburetor.
An additional wrinkle in all this is that when I went looking for the reference info everyone has been mentioning that should be under the hood I discovered someone has painted the underside of the hood black. This further supports my theory that the engine has been replaced so they covered up the labels. I think it’s the right engine just maybe it started it’s life in a different car or truck. Any suggestions you all have to positively identify the engine will be greatly appreciated.
BTW, thanks for the suggestion on just replacing all the vacuum lines. That sounds like the easiest answer so I’ll give it a try.
Thanks!
matthew900
03-16-2009, 02:29 PM
Hi, I installed the manual choke pull this weekend and discovered something weird. The choke will not close unless you push the gas pedal down when you close it. Is it supposed to do this and/or is it a big deal? Thanks!
Megunticook
03-16-2009, 02:54 PM
That's how mine is, too...starting procedure is push accelerator to the floor and hold it, close the choke fully, release pedal, crank, and as soon as it fires up open the choke a little bit. You'll get the feel for it, you can really fine-tune the adjustment based on what the motor sounds like. After a while you won't even think about it. Obviiously when the engine warms up you open the choke fully.
On mine if you pump the pedal it floods right away, so you have to just push the pedal down once initially.
