Carb question and starting issue

Our club groomer is a 1969 Bombardier. It has a 250 in it. With help from this site I've got it running very well.
I put a head from an 82 Cougar on it a year ago and it ran sweet all last season.
Years ago I put a carb from a 1986 F-150 (with a 300) on it. It has worked very well ever since. Starts right up and runs smooth.

When I was moving it around this fall it was getting hard to start as it got colder. I had put fresh plugs in it but I may have the gaps too wide.
It has a Pertronix ignition in it.
It tries to start but runs on one or two cylinders and then suddenly jumps up onto all 6.
Saturday it took a LONG time to get it started and I had to play holding the choke plate to get it to run. It has an electric choke so if it takes a while to start that electric coil will open the choke.
When it did finally struggle to get running it had a dead cylinder which turned out to be a fouled plug.

I have not done anything with the carb for several years and it sits most of the year. I'm planning to rebuild the carb and put fresh plugs in it.
I'm planning to use a .030" gap instead of .040" this time.
I also have the carb from the 1982 Cougar which looks far more complicated.

Question, do I rebuild the one on it, or do I rebuild the Cougar carb and use that? Which would run better?
Any advice would be helpful.
Thanks,
Mel

I too am having hard start issues. No solution, just have to keep pumping the gas until it goes.
But I would stick with that carb you got off the 300, probably a YF.
I have the original holley 1946, and it won't solve your problem.

40 should be fine with the petronix, some people are running 50. 35 is the typical spec for a points system so I would not go any smaller than 35.

The truck carb likely has less emissions related oddities and tune on it than the cougar one would have so I am thinking staying with the truck carb would be good.

If its got a Ford choke on it it should be connected to a special terminal on the Ford alternator. It should not have any power on it till the alternator is spinning at a few hundred rpm (engine started). At that point it should read around 7 volts IIRC. Once you got into the computer controlled era the chokes were 12V and I think were run from the computer. Other makes used 12V chokes and there are only a few basic designs of those choke heaters so its possible to get 12v or the original 7v ford ones to interchange. GM ran theirs through an oil pressure switch. Key on 12v to the switch, below 5 PSI oil/choke light on dash lights, above 5psi (engine running) power goes to choke coil. This way you can have the key on and it wont start heating the choke. Most likely with a lot of cranking you would generate enough oil pressure to start heating the choke but at least its not as bad as just coming on with the key.

Also its worth looking at the choke pull off. Im not sure what that model uses but all carbs have some sort of a pull off method and a way to adjust it. Chokes should close all the way when the engine is cold and not running. Once they start (or at least create some vacuum) the choke should open slightly to some sort of a preset. Some carbs have a vacuum motor (sometimes called a brake) to do this, others just depend on the weight and balance of the butterfly acting against the engine vacuum. These usually have some sort of adjustment somewhere to control how far they open. On the 1100's there is a little plastic nut.

Hi all.The stud on the alternator for the electric choke is the STATOR stud.Learned that form the forums here.
Leo

Excellent info on that choke. I have it wired direct to key on 12v. I remember on my Corvair I ran a Holley 390 with an electric choke and it was grounded through a gizmo that bolted to the cylinder head. Once it detected heat it started to pull the choke open.

New plugs coming. I'll gap at .030" just to be sure. Starting at -10 is tough sometimes.

The alternator we're using isn't original. It's the same as what the postal delivery vehicles use. 105 amp or so. The groomer has so many lights added on that we needed to upgrade the electrical system some. I don't know where I'd connect on that alternator to get the delayed voltage. As it was I had to put a resistor on it to make it charge correctly. It used to go insane every now and then and imagine it was a welding power supply. Pretty hard on stuff that burns...

I ordered the carb kit for the truck carb. I'll stick with that. I might try the relay through an oil pressure switch to power the choke or maybe just try to convert it to a manual one. We have a gauge for the oil pressure but I might be able to find a switch that closes at 20 psi or something like that.

If there is more info on this, just keep it coming.
Thanks for the help.
Mel

Mel,

While you re at it, you may want to check that all plugs a firing well. You could possibly have a weak or failing coil.

Josh

Yeah. I check wire to wire with my timing light to see which ones hit bright and consistantly. They all do once it's running.
I'll check it again while cranking after I get the stuff changed over.