The Stovebolt Site Forums The Shop Area Engine Shop Problem with newly rebuilt carb

I just had the carb off my Canadian built 1948 219 1 ton rebuilt buy a reputable rebuilder. The engine started and ran well before the rebuild now it won't start.
I tested the fuel pump and it's pumping gas to the carb. I have spark because when I pour gas down the throat of the carb it starts and runs well on that gas - then quits. Pumping the accelerator doesn't help. Choke and accelerator linkage seem to work fine. Nothing else was done on the engine while the carb was away. The rebuilder is as puzzled as I am.
Andrew

Well, if it has gas in the bowl and the accelerator pump doesn't squirt gas when you pump the accelerator my guess would be the rebuild is bad. I'm not a mechanic but if the carb is getting gas and it's not feeding it to the engine, that's a pretty darn good indication that the problem rests with the rebuild... assuming of course the idle screw isn't closed.

But, what the heck do I know before my second cup of coffee.

I checked the idle screw is open 1 3/4 turns. Then I opened the choke and while looking down the throat pumped the accelerator linkage - it pumps gas into the throat.But no start.
When I pour some gas down the throat it starts up just fine and runs 3-4 seconds. While running I pumped the accelerator. It seems to run a bit longer on that gas but then maybe it doesn't make any difference. It certainly ran very rough while pumping the accelerator until it quit. Seems it's getting some fuel but perhaps no where near enough. Beats me.
I tightened the carb mounting bolts on a new gasket to be sure its not sucking air. Should I try a new manifold gasket it case its sucking air through there???

Then in my amateur opinion it sounds like the only gas going through the carb is coming out the accelerator pump if you have no idle and rough running above idle and ony when pumping the accelerator.

I sure hope someone who knows what they're talking about jumps in here 'cause I'm outta' guesses.

Andrew,

If you the rebuilder is nearby and you have any type of dialogue with him, I certainly would take it back and have him give it a post-op inspection...something isn't right, obviously.

The only other issue might be junk that got into the needle/seat area when you installed the 'working' carburetor. This would prevent the bowl from filling properly, although you indicate the accelerator pump squirts when actuated.

The base must be gasketed and tight. You also indicate this has been done properly. If you did your part, then the rebuilt carburetor should work. If it doesn't, the rebuilder should have no problems taking a look at it. Make sure all your bases are covered before you take it back to him!

Stuart

Try pumping some of that gas you're getting from the tank into a bottle, pour a little out on the ground, and toss a match into it. I'll bet it's hard to light, or it won't burn at all. I've seen situations where gas went stale enough in a very short time that the engine simply wouldn't run on it. It's also possible a little condensation formed in the tank, and you're actually pumping water, not gasoline.
Jerry

I am trying to exhaust all options before returning the carb to the rebuilder. By the way, he most recently suggested that the reinstalled carb could be sucking air somewhere. Although it is bolted tight I didn't put any gasket sealant on the join so I'll try that. The gas is fresh from the pump. The engine started and ran fine before I sent the carb for rebuild 3 weeks ago.
Thanks for the input so far.

If it ran fine then why did you get it rebuilt?

Andrew,

I wouldn't recommend any gasket sealer on that deal. Clean surfaces with a dry gasket between insulator and carb base is all that's required..NO GOOP!

Stuart

Im going with something stuck in the needle and seat.
It happened to me in the Calif. Sierras one NIGHT. It drove me nuts,,then a friend suggested checking the needle and seat for crud,and guess what......................
The N/S assembly had vibrated loose and wasnt letting gas in.
And all this time,working on it with just a Bic lighter for light.
Livin on the edge..................

I have to agree with Stuart! It sounds like something has lodged the needle valve and not letting gas into the carb. Mine had an air leak but all it did was make it run and idle rough: it would still start. Do you have a gas filter in-line before you get to the carb? If so, did you remove it when you took the carb. off? The gas filter goes on only one way. If you have one and removed it, it may be possible that you put it back on backwards and this maybe the cause. Hope this helps!
John

It ran fine at a driveway idle but couldn't handle the accelerator. After being parked for 15 years or more I belived it at leasted needed a kit.

Thanks for this input group, much appreciated. I think my next step will be to tighten up carb and manifold to deal with possible air leaks and keep up the vacuum in the throat (with no gasket sealer). After that I'll check the needle valve and install an inline filter (there was no filter on the gas line, only the strainer).
Thanks again.