Thread: 1966 c20
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Old January 8th, 2015, 02:17 AM
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GMCDAC GMCDAC is offline
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Location: Green Valley, east of Rapid City,SD
Truck: I have 4 GMCs, none with a V-6 - YET! Have had 2 in the family.
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Default Re: 1966 c20

Quote:
Sorry I haven't been updating, but for some reason the Tapatalk app won't load this forum, and my iPhone won't open it either! (unfortunately all my pics are on the iPhone, so ill have to sort that out late).

So, the headlights! i spent about an hour and a half drinking with my volt meter testing the headlight wires every foot to a few inches from start to finish, didn't find anything. Finally looked closer at the headlight (like i should have in the firs place) and found that it was broken and full of water. replaced both lights with two new ones, and, LET THERE BE LIGHT! not a single issue in the darn thing! now unfortunately my volt meter crapped out on me, so I'm hoping the tail light on the same side is the same issue (a new tail light bulb is only like $3.50 anyways). my right rear blinker works, but some idiot cut the wires on the front blinker between the fire wall and the hood, no left blinker at all.

I'm still having the startup issue though. I bought a carb rebuild kit thinking i would rebuild it (it turned out to be a general rebuild kit, so a lot of spare parts and i was lost!) so about half way through i decided I would just brake clean parts of it, replace the jet and needle, then replace the fuel filter and gaskets and i would just put it back together. Now it leaks gas through the gasket and it STILL doesn't start!!! when i get some time (either in the morning tomorrow, thursday, or some time friday) I will take the carb back off, and (depending on how motivated i'm feeling) either take it apart again and carb dip it (costs money that i don't have) or just trouble shoot it as much as i can.

things i know so far:
1. when fuel line is put in a bottle and the starter is turned over it will squirt fuel into the bottle
2. fule filter is clean
3. the carb will be getting an air filter soon
4. Motorcycle carbs are NOT, i repeat, NOT the same as these carbs!
5. i changed the bottom of the float to the float bowl measurement from 1 7/8" to 1 3/4" as the instructions said to.
6. if i dump even a little gas into the carb it starts up fine with no issues
7. I will be removing the choke line and just adjusting it by hand until the truck is warm, then I can go and drive somewhere. (choke cable keeps binding)
8. I wouldn't mind (at all) if i could just put a small edelbrock or holley carb that i understand how to use on here, but this one is kind of fun to tinker with (though i would appreciate being able to afford to think more)

any tips on carb work? its a rochester monojet "B" series (B for basic?? lol) i found some videos on youtube, but the guys on there seem to have some bad habits.
Quote:
Also, are those hinged gizmos by my feet a cold / fresh air vent for the cab?
Yeah the B is pretty basic, but like all old carbs a good bath in carb cleaner should be the first order of business. Since you said gas is leaking around the gasket, I am assuming the gasket between the top plate/air horn and the float bowl body. That means the fuel bowl is overfilling and normally stuck or damaged needle and seat or binding floats cause that. Too high of a float level can too but you said that you went with the lower measurement.

The model B has two connected floats and they must be parallel or flat with each other and must not rub on the carb body anywhere through up and down travel. Like I said in my earlier post your model B may need to have a throttle cable as well as the choke cable to keep the idle high enough to run while the engine is warming up. That is why I built a Rochester model M, choke cable is all that was needed.

Many of these V-6 folks here have knowledge of other 1 BBL carbs, but I'm not qualified to say. Most seem to do a 2 BBL.

Pics of my Model B carbs and of the Model M that I put on my 230.

Oh yeah those hinged gizmos are fresh air vents.

DAC
Attached Images
File Type: jpg Rochester modelB 001.jpg (781.0 KB, Multiple views, 7 clicks)
File Type: jpg manifold swap 010.jpg (1,014.6 KB, Multiple views, 7 clicks)
File Type: jpg Rochester M kit 001.jpg (774.5 KB, Multiple views, 6 clicks)
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Doug Crawford
Rapid City, SD

1970 GMC K5 Jimmy Mom drove 30 years
1972 GMC C2500 owned since 1979
1955 GMC 100 driver-project
2006 GMC Yukon Denali---wife's truck

Hope to have a '60 GMC Suburban again someday
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