MTFCA Forum

I bought a rebuilt carburetor about a month ago, the car has been running fine. Yesterday I wanted to take advantage of our nice Indiana weather and go for a ride, It wouldn’t start, I started checking things over, spark was good so I moved on to the fuel system. Took the line off at the both ends blew out the fuel line, that wasn’t it. For some reason the carburetor wasn’t letting gas in. I put a different carb on and finished my ride. What should I check first?

Does your rebuilt carb. have a Grouse Jet in it? I had one once and it would stick open or closed. If it sticks closed, the carb. will get no gas and won't start. If it sticks open, gas runs out all over the place.

Keith

Have to agree something is sticking inside the carb. When the carb was on your car did you open the drain on the bottom of the carb to see if gas would run out? Probably a stuck float valve. If you’ve only had it about a month call and ask what kind of float valve is in it. Did you tap on the carb when the car wouldn’t start? If it would start a sticking valve is the issue.

I’m not sure what kind of jet it has Keith. I did open the bowl drain John, it was dry. Yes I did tap the carburetor to try and free up the problem. So, do I take off the bowl? It’s a NH carburetor by the way. I’ve never had one apart before, not sure what I’m looking for.

Bet anything Keith is right. My money says it has one of those stupid Grose Jets. Perfect name for them, because they ARE GROSS!! LOL. Pull the bowl, you can see by looking if there's a little round shiny ball staring at you. Had a late friend experience the exact same problem. Go for it!

[image][/image]

When they are saying Grose Jet, they are referring to the float valve, not the needle seat that you are showing in the photo. Grose Jet is a particular style. Slide out the pin holding the float in place to reveal the float valve to see which style it is.

I had a Grose jet that worked for years and another one that lasted days. Some are good some are not.

The float opens and closes the float valve to control the flow of gas to the bowl. When the level is high the float rises and pushes the float valve closed. When it is low the float drops with the fuel level in the bowl and opens the float valve allowing fuel to flow into the bowl. A stuck closed float valve will not allow fuel to flow and your bowl will go dry, a stuck open float valve will allow fuel to pour out of the carb untill your tank runs dry. Knocking on the side of the carb will often temporarily free a stuck valve, good to know if your carb is pouring gas out on the ground. Long term solution is to replace the float valve and seat. Last I looked there were 2 options, a grose jet, that is a series if ball bearings instead of a needle, had one once, dont use them now, or a viton tipped needle. Origionals were not viton tipped, but solid brass needles have not been available for years.

View of the ball style Grose float valve, one-piece with seat, unscrewed from the carb. The float has been removed by pulling the float pin from the hinge.



These stick in the closed or open position and can cause leaks or shut off gas flow. They aren't designed for gravity fuel systems.

You could use the Vitron tip style made similar to original, but sometimes these stick if fuel is left in the bowl at storage.
IMO, the original steel type are the best, if you fit the needle to a new seat, the seat the original type, by slight tapping and spinning, to have the angles of both the same.

Also, first 'dress' the tip in hard wood to burnish the finish very smooth.

The needle and seat is the original type valve. Viton works very well in that location. I have had a grose valve in one carburetor and used to run out of gas going uphill. Replaced with the needle and seat, no more problems.

If you have a needle and seat, one thing which helps keep it from sticking, is to tap on the carburetor near the fuel intake Not a hard tap, but a gentle one when you close the fuel valve when you park. That will help to keep the valve closed while parked. When you turn on the gas, wait just a minute to be sure gas does not come gushing out the carburetor. If the valve sticks open the gas could overflow.

Most of the time with a good needle and seat, you will not have a problem, except if the car has been parked a long time. Then a tap usually fixes the problem.
Norm

Steve Jelf wrote: ↑

Sun Nov 08, 2020 11:45 pm

Why would anyone install one of those things when rebuilding a carburetor?

Steve, as I recall, a while back you could not get the needle type valve. I believe someone is making them again.
Even with those, I have found a light sanding on the 3 flutes keeps the needle style from also sticking...I've had that happen to me.

There is also a third option:

Note that the one Scott makes is solid brass with a viton tip and is heavy enough to pull away from the seat if your gas is slightly sticky.
Nothing will work in old shellacky gas.