Carb Problem?

[siii8873]

I am just starting to run my SIII after a lengthy restoration. It has a 2.25 petrol with a zenith carb. The engine starts fine and will idle OK if it is backed off to idle VERY slowly. If I give it some throttle and back off at anything faster than a snails pace it stalls. When I last ran the vehicle (years ago) it ran just fine and I did no work on the Carb.
Anyone have any Idea what may be causing this.?
Thanks
Bob

[Roverowner]

My first thought is fuel filter. Easy and cheap to change, so do it and see if that helps. Could also be gunk on the screen on your fuel pick-up tube in the gas tank. Make sure that your fuel line doesn't have a split in it, especially where the line connects to the fuel pick up, and is sucking air. If those things don't clear it up, dump some fuel injector cleaner in the tank and let the car idle for a while so it can get into the carb and disolve any varnish that may have built up. Also remember, 90% of all fuel problems are electrical so check plugs, coil, dizzy, plug wires, timing, and points if the fuel tips I gave you don't sort it out.

[Donnie]

I'm not sure if Rover/Zenith ever used a dashpot to slow the throttle plate closing, but GM did.. this is a little "shock absorber device" attached to the linkage at the carb...None of my units use this carb...Donnie

[siii8873]

Couple of things, fuel pick up tube removed and in great shape, new fuel filter, fuel lines,new points, plugs, condenser.
The engine accelerates fine it's just a deacceleration problem. Wouldn't a fuel clogging problem or air leak cause more of a problem with acceleration?
I do plan on checking the fittings before the pump, anything after I would expect to leak. I also have a new set of plugs to install. I left the old ones in for a while because I didn't want to foul them when I first started/ ran the vehicle ( I had put some oil in the cylinders on occasion and turned it over with the hand crank occasionally during the idle period)
I will say that carbs are not my thing.

[BackInA88]

Is this happening while you are driving it or in your driveway?
Does it sputter while it dies or is it like you turned of the key?

There's only a couple things I can think of that might cause this.

Maybe a bad wire in your distributor? When you let off the gas the manifold vacuum goes up and maybe this is moving your vacuum advance plate enough to cause an old frayed wire to ground out the points?
I'd check this one first.

The throttle plate closing off to much and the idle jets and slow speed fuel bleeds being plugged? Have you tried cranking up the idle speed and removing the mixture screw and shooting in some carb cleaner in the hole.

If it is happening while driving maybe the float level is to low and the fuel is sloshing to the front of the bowel and the pick up tube sucks air?


Good Luck,
Steve

[Les Parker]

Hello there,

I had a similar experience with an Ex-MOD 88" that had been stored outside for 5 years.
I eventually took the convoluted hose from the carb to the air cleaner off, to find that it had become a sanctuary for the local rodents storing their acorns and hazlenuts. In total I removed 1.5 lbs of nuts from the hose, then I got the potential of the 2.25 engine.
Maybe this could be the source of your restricted air flow, causing idling OK but no high revving.



In fact, Bob, maybe they were relatives of the rodents in your area, as the vehicle was less than 3 miles as the crow flies.......

[sayers]

How old is the zenith carb. ? I installed a new one last year , around February and had the same problems with it. It turned out that the allotment from england had some defects. IE a loose idle adjustment screw. Everytime I got it idling correctly and then would drive it the screw would work loose and stall out the truck. This was on a brand new carb. I solved the problem by putting a drop of loc-tite on the screw and it works fine now. good luck

[siii8873]

I'm sure it's not the air inlet hose as it does it with it disconnected and it's new. When it quits it sputters and then stalls, and it won't stall if I back off the throttle VERY slowly. When I do this it idles but not the greatest, it will sputter a little but keep running. If i'm on it and give it some throttle it will recover and keep running. It does it sitting in the garage. It has been sitting 3+ years as I have been doing a restoration on it and I'm just now getting ready to put it on the road.