2f Carb Tuning - Timing - and Vacuum Routing for Desmog (1 Viewer)

[g-man]

The sensor for your carb fan is under the exhaust manifold. Closer to the firewall. If you get under the truck and look up you may see it. All that may be required is connecting the wire. Attached to the sensor there may be a short piece of wire with white jacketed insulation. I'll take a pic of mine in the morning for you.

It's possible that your timing is still retarded too much if your engine is overheating when you stop it, or you are sitting at a light and notice the temps rising.

 

[g-man]

I'm guessing the dieseling or run on after cut off is related to the rich condition

 

[dannyvp]

For now for the carb fan, add a few inches of 18g to as clean a stretch of what’s there and ground it to the fender. It should come on when you shut the truck down.
To do it right will require a fair amount more work so half assing is totally acceptable.

I’ve been wanting to strip that wire back a ways and splice it. I’ll do that this week.

I’ll also order a little rubber cap from ragingmatt for the oil sender. I have a little list going for him anyways.

 

[Casey E]

Not sure what you have going on here but this could be the issue if it’s leading too the intake.

 

[dannyvp]

I'm guessing the dieseling or run on after cut off is related to the rich condition

I think it might have idling fast for some reason after it heated up. I lowered the idle and when I drove it back home it didn’t diesel any.

 

[dannyvp]

Not sure what you have going on here but this could be the issue if it’s leading too the intake.

View attachment 2042742

That’s a line that goes through the firewall I think. No vac on it. I just folded it over. It did have a bolt in it.

 

[Seth S]

With a full and proper desmog, set valves, and carb dialed in I haven’t had much need for my non wired up carb can. If it won’t start when hot I just give it about half throttle while cranking and it fires right up.

 

[NeverGiveUpYota]

It's possible that your timing is still retarded too much if your engine is overheating when you stop it, or you are sitting at a light and notice the temps rising.

Not related. I’ve never ever been told or read that this is a probability.

 

[Seth S]

Never heard about retarded timing causing overheat but did some reading and understand why it’s the case. However I think it’s important to note that the cause of more heat in the case of timing retarded too much is much safer than the heat damage that can occur from too much advance. Too much advance will of course result in preignition (pinging) or knock (detonation) and these are the ignition events that melt and crack pistons. With a cooling system up to par and the fact that you have a slow spinning industrial engine I’d not be worried about the “too retarded” timing condition.

Temp gage pinging hot after shutdown is likely just heat sinking raising the coolant temp. Startup recirculates the coolant and it drops down again

 

[g-man]

Not related. I’ve never ever been told or read that this is a probability.

This from wikipedia on retarded timing: If the spark occurs too retarded relative to the piston position, maximum cylinder pressure will occur after the piston is already traveling too far down the cylinder. This results in lost power, overheating tendencies, high emissions, and unburned fuel.

And this is exactly what happened in my 2f when I replaced the head and put the timing on the BB. My truck is partially desmogged. I was experiencing higher than normal engine temps while sitting at idle ...like at a street light after getting the engine temps up to normal. And the temp gauge would get near the red when I turned off the engine. They would of course come down to normal temps as soon as I was moving at speed.

Advancing the timing made this go away.

 

[g-man]

Here is the pic of the temp sensor for the carb fan. It is mounted to a bracket that is mounted to the intake manifold.

 

[Seth S]

The correct answer is to set the timing to spec and then make sure your distributor is working properly and if needed have your advance recurved.

 

[dannyvp]

Here is the pic of the temp sensor for the carb fan. It is mounted to a bracket that is mounted to the intake manifold.

View attachment 2042976

I may or may not have that. I’ll have to look, I do remember something I think though.

 

[dannyvp]

Well jumped in my truck today and it left me on the side of the road when I pulled out in traffic, luckily I had enough momentum to get across the street.
I made a couple small adjustments to the carb and it seemed to want to run.
At the next red light I was watching the RPM’s. It went from 1000 to 1500, I pulled off and it started bucking and jumping, I pulled over and it died...... here I sit in the rain.

Update. Sitting at the library. Made a few adjustments. Truck will run if I pull the choke out a little bit. Push the choke all the way in and it dies.
I think in my haste of sitting in the middle of traffic trying to get my cruiser out of the way, I may have adjusted the choke screw on the carb. What is the proper adjustment for that?

 

[NeverGiveUpYota]

Choke should be at about 1800. If you have to you can drive w/ the choke out a smidge to get you where you need to go. All this is a real finesse. A big pain in the ass, but your on your way.

 

[dannyvp]

I got it home with a little choke.

 

[dannyvp]

I found this in a box. It doesn’t happen to be a temp sensor does it? It’s pretty small, think quarter sized.

 

[g-man]

Thats the temp sensor for the carb fan. Bolts to the intake manifold. Just need a small bolt w/12mm head on it. that is the pcv hard line that goes to the side of the intake. Just cut it off the pcv line and bolt it to the intake.

 

[g-man]

BTW you can cut 3 or 4 inches off your pcv hose and snap it into the 2 holders for it on the back of the air cleaner so it's not sticking up in the air.

 

[dannyvp]

Thats the temp sensor for the carb fan. Bolts to the intake manifold. Just need a small bolt w/12mm head on it. that is the pcv hard line that goes to the side of the intake. Just cut it off the pcv line and bolt it to the intake.

So this sensor just needs to be close to the manifold when mounted.