Rotarx7

iTrader: (3)

i put seafoam in my cars gas tank about 2-3 weeks ago. i know its supposed to smoke a lot but its been weeks already and ive been through about 3 full tanks of gas. it only smokes a lot on start up for the first minute or 2, after that its cool. is this normal?? ive noticed a huge difference in my cars performance since then. it starts up faster, and idles smoother. all that smoke just gets embarassing, esp while youre stuck in a parking stucture with a lot of people around covering their noses.

trochoid

iTrader: (6)

Engine is getting tired and oil control o-rings are worn/hard. If it didn't smoke before the Seafoam then the carbon buildup was masking this and the Seafoam cleaned out enough carbon for it to show up. Live with it until you're ready for a rebuild. What weight oil are you running. 20W50 may reduce some of the smoking. You might try an oil additive, don't recall what brand has had some success.

slow5oh

lucas oil stabilizer is my personal favorite.

trochoid, my car has this same smoke on start issue, but its been rebuilt in the past 20k miles and it runs like a scalded dog. is this due to a fault in the rebuild by the previous owner? also, what is the life expectancy on a 13b once the oil control rings start to go. ive got a 110 mile per day commute, and have recently been considering spraying a 100 shot at the drag strip at the end of april. just trying to get my bearings on whether i need to expect to put a motor in anytime soon.

DivinDriver

iTrader: (15)

I'm working against a smoke-on-restart issue myself... but its not oil smoke, it's fuel smoke, from a tendency to flood after a hot shutdown that I have yet to solve. my carb bowls drain into the manifold somehow after the car is shut down. It's got a lot of local rotorheads puzzled.

The smell is the main clue, even more than the smoke color; if it smells like burned oil, it's oil control. If it smells like raw fuel, it's a flood issue.

Putting Seafoam into the gas tank didn't seem to me to produce any significant smoking.

slow5oh

mine is most definately oil smoke. whats strange to me though is that despite the smoke on startup my car doesnt burn more than a quart in a 2500-3000 mile interval.

orion84gsl

iTrader: (5)

The cause of that I believe is temperature drop inside the combustion chambers. When the air temp inside the engine drops the air gets more dense, so it sucks in outside air, through the carb, pulling fuel with it. As it heats up during the day the air gets less dense and pushes some air back out, leaving the fuel behind. Do this over a few nights and that's your flooding problem. This is hypothetical but it makes sense to me. It took me 45 minutes to start my car because it was flooded yesterday. I had it parked for the winter and started it about a month ago, but I shut off the fuel pump and let it stall out, so I'm not sure how it flooded again, but it did. Spark plugs were soaked.

Kentetsu

1. Seafoam in the gas tank will not produce visible smoke, even at a rate of 1 can to 1/8th tank of gas.
2. If you overfill the crank case with oil, you will blow out the oil control rings in short order. DON'T DO THIS....
3. If you are producing oil smoke, then you are dealing with bad oil control rings. This is a nuisance, but will not shorten the life of the motor.
4. I have had great success in dealing with bad oil control rings by using Lucas Heavy Duty Oil Stabilizer. Cleared up 95% of my issue on my old motor, and it was so bad the car was no longer drivable before I used the Lucas.



Divindriver, some things to check for flooding after shutdown (assuming carb):

1. Restrictor in return line. Is it there? Is it clogged? Is it pointing in the right direction?
2. There is a small orifice that can get clogged in the carbon cannister system that will also cause this.
3. Leaking float needle valves.

That's all I can think of at the moment...



.

orion84gsl

iTrader: (5)

There's also the possibilty, however slight, that some jerk is running around while you sleep pouring gas down your carb. Unlikely, but weirder things have happened.:P

Rotarx7

iTrader: (3)

ok thanks guys. time to get some Lucas i guess and see what happens

Percentage

iTrader: (7)

This may seem like a dumb question, but where are the oil control rings located in the motor?

BlackWorksInc

The Oil Control Rings are located on each side of the actual rotor itself, they fit into grooves in the rotor and prevent oil from the eccentric shaft cavity to flood into the engine.

I don't have any pictures on me right now...

DivinDriver

iTrader: (15)

They are on the flat front and back 'sides' of the rotors, surrounding the e-shaft. They press against & slide on the faces of the side plates.

Carbed 80 12A

1. Restrictor is in place, blow-tested fine before install, and the little arrow that points to the carb is pointing at the carb.
I actually have a brand-new-in-the-bag spare, and may break down and install it for testing purposes.

2. Don't got none. My carbon canister is in the lid of the air cleaner; entire bottom is open to the carb through a mesh screen, and the bowl and crankcase hookup tests as free-flowing.

3. Thing is, the bowls don't fill with gas after shutdown, they drain down (fuel level drops), over the course of an hour or two, rear bowl faster then the front. Which shouldn't be possible, considering the carb design - - should need vacuum to lift the fuel out of the bowl.

Only way I can think of that this could happen, is for air pressure to build up within the bowls... but they are vented, supposedly.

It's quite a puzzle. I'm thinking of jimmying the bowl vent solenoid to "force" it open all the time, and see if this makes a difference. It's possible the thingy is sticking, and not venting the bowls after shutdown like it should, but it's not "observable."

DivinDriver

iTrader: (15)

Jinx!

waysrx7

^^^ DivinDriver here is what I see happening. With your car running (ie. ignition on) the air vent solenoid valve is 'on' allowing air from the top of the carb to enter the fuel bowls, this is good as it allows equal pressure inside and outside the carb fuel bowls.

But as soon as you turn off the car the air vent solenoid valve is 'off' and this cuts off the air supply from the top of the carb to the fuel bowls and instead uses the opening to the left of the air vent solenoid to 'equally pressurise' the fuel bowls with atmospheric pressure.

I think when you turn your car off that opening with the hose connected to it beside the air vent solenoid is pressurizing your fuel bowls somehow which would force your fuel out as you described.

After driving your car, try unhooking that hose and see if it makes a difference that way you will at least know it isn't your problem.

trochoid

iTrader: (6)

Fuel return line restrictor arrow should point AWAY from carb. It not only restricts, acting like an FPR, it is also a oneway valve.

Kentetsu

You beat me to it Scott!

waysrx7

Really??

If your talking about the little metal thing in the fuel return line, mine says CARB and has an arrow that points TOWARD the carb the same as in the 1980 FSM.

waysrx7

After looking at the FSM it looks like the easist way to test my theory is to try to blow air through the top of the air cleaner lid. If you can then forget everything I said in my first post, if you can't there is your problem.

DivinDriver

iTrader: (15)

Well, that's pretty confusing, because the imprint on the part reads thusly:


<-CARB



(photo imcoming)



To me, that has always meant "the carb should be THAT way." I've had it that way for years.

Seems like if I had it backwards, no fuel would ever go down the return line, and the carb would backflood while the pump is running.

You guys are SURE I'm wrong?

drifter403

iTrader: (2)

man i sea foamed my car and that **** smoked more than i do at the hooka lounge... and it ran smooth

DivinDriver

iTrader: (15)

I did, and it does - - air blows into the carbon chamber without restriction.

I tested my spare return line gizmo; air will blow thru it only in the direction opposite the arrow.

trochoid

iTrader: (6)

My mistake, I was thinking the arrow pointed in the direction of fuel flow, which is away from the carb. I stand corrected. I believe it's a oneway valve so when the tank pressurizes, vapors are forced into the charcoal canister/lid instead of pushing the remaining liquid fuel in the return line back into the carb.

Kentetsu

Wow, are we wrong, or did this change at some point during production? I thought the arrow indicated the direction of flow toward the gas tank.... Where's Sterling when you need him? lol...

Sterling

Actually, the "restrictor" is nothing more than a check valve.
The regulator is inside the carb; the pip that holds the rail assembly together & to the carb has a small orifice in the side that restricts the fuel rate going to the return line. The diameter of this varies from model to model (I've seen 3 different sizes so far). This orifice is TINY compared to the "restrictor" checkvalve. Blowing through both would demonstrate that the "restrictor" is not doing much restricting.

BTW, I have several, but some don't even have an arrow on them. You have to blow/suck through some to tell which way to install them.

Sterling

DivinDriver, with the engine off there are 3 ways the carb can only leak all the fuel out of the bowls;
Lefts side fuel bowl could only leak into the idle circuit. It's the only circuit low enough for it to happen. This could be the result of siphoning due to a plugged transition jet and / or idle air bleed. Of course, the same thing can happen to the right side fuel bowl, but the right side fuel bowl has two other possibilities, as well.
The accelerator pump gets it's fuel source from the AP. The only way the AP can drain the bowl with the engine off is if the housing cover is loose and it's leaking out the cover. The fuel has to go up-wards to enter the carb otherwise.
The other way the right side fuel bowl could drain with the engine off is through the richer circuit. This is a complex circuit with 6 terminations, two of which are located in the fuel bowl (right side) and one of which is a giant port that terminates in the rear primary throttle body bore, below the throttle valve.
-Of course, if the carb isn't from an automatic, it doesn't even have that circuit. But if it does have it, the solenoid could be jammed or the weight could be stuck (somehow).

The circuit goes up and then down, but it only goes up to about as high as the fuel level that the floats are supposed to be set at. So if your float setting is slightly higher than 1/2 way, the fuel can travel up the circuit path and then back down through into the manifold if the solenoid is stuck open.
The richer circuit has one port way down low in the bowl, so it could suck it dry, and one way up above the fuel level, providing a great vent.

The FBVS doesn't really seal the carburetor all that well. It seals only enough to be a problem if it's closed during fuel demand. I don't think your problem is related to it.

So try these and see what you get.

More can be found about how to properly block off the richer solenoid circuit on my Nikki troubleshooting page.