I recently sent my 38's W1 out to be rebuilt. Since I got it back and reinstalled, it seems the needle valve has been sticking on occasion. It'll act like it's running out of gas but I can keep the engine turning (albeit poorly) by pumping the gas pedal, activating the accelerator pump. After a minute or so it unsticks and off we go. I hate to blame the rebuild but it never did that prior to the rebuild. I did recently go through the process of replacing the gas tank because it appeared the Redkote liner in the old one was failing so it's possible some residue from that old liner has coated the needle valve and causes it to stick on occasion. Pursuing that theory I've been putting a high dose of fuel system cleaner in the tank when I drive the car, hoping the cleaner will dissolve any liner residue on the valve, so far to no avail. I burn E10 and my thinking is the alcohol is a very good solvent so eventually the combination of fuel system cleaner and alcohol in the gas will remove any residue that may be present, IF there is any present. I'm starting to have my doubts. I really hate the thought of having to tear in to my freshly rebuilt carburetor. Since my ankle surgery, getting into and out of the car and even driving it is a chore so the thought of possibly having to so some roadside carburetor work or call for a rescue ranger is distressing. If the issue continues I will be forced to open the carburetor to inspect the needle valve. What is a good solvent to clean the valve and seat if that becomes necessary?
Last edited by Tiny; 09/17/2309:51 AM.
VCCA Member 43216 Save a life, adopt a senior shelter pet. 1938 HB Business Coupe 1953 210 Sedan
Not sure I agree with your diagnosis (and I don't have a better one); but we have used Dawn dishwater soap for dirt and grease, and the auto choke cleaner (in the spray can) for carbon and varnish.
With modern gasoline gum and varnish can form fairly quickly. It can be very sticky and takes extremely little to stick the needle. Small amounts of carb and choke cleaner can remove it. Removing the needle wiping it with carb cleaner and then saturating a rag or paper towel, then craming it into the seat and roating can be very effective.
I believe I found the problem. I popped the top off of the float bowl and removed the float & needle valve. I discovered RTV debris between the valve and valve seat. I have no clue how it got into the fuel system since I don't use it in any fuel system application for this very reason. I was a bit surprised by the needle valve. The valves I've dealt with in the past were pointed where this one is flat. An inspection of the float bowl showed more RTV debris which I removed. A minor float adjustment later I put it all back together after filling the bowl with gas to facilitate the restart, started the car and it ran like a top. A longer test drive is in order after my son and I team up to do a minor tune-up. The photos below show the needle valve with the piece of debris that was in the seat, the seat after removal and the debris I found in the bowl.
VCCA Member 43216 Save a life, adopt a senior shelter pet. 1938 HB Business Coupe 1953 210 Sedan
The fuel valve pictured was designed, patented, and originally produced by Parker Brothers, out of Oklahoma. Several decades ago, we were one of their customers. The valve does have several advantages over the pointed valve, but price is not one of them.
A couple of decades ago, Paul Parker closed the business.
When Paul was still in business, we bought and used tens of thousands of these valves with no issues.
It is my understanding that Daytona purchased the rights to the Parker design (originally called "The Master Float Valve") and is now producing the valve. Since we now make our own special valves, I have not personally seen or used the Daytona version.
While Paul had many standard valves, he would also do custom work. We could submit samples, and he would produce special valves in quantities of a hundred. The companies that make the pointed valves will at least talk to you if you want 10,000 non-standard valves, but may still not accept an order for only that number.
Tiny In your first post about this issue it was mentioned the “Redcoat” liner in the old gas tank was failing and that tank was replaced. Could the residue now referenced in this later post described as RTV actually be remnants of the Redcoat liner from the old tank? That would be my guess.
I don't think so. Redkote is a rock hard bright red coating. The debris is black rubber. After further consideration I think I know where it came from. I recently replaced the fuel pump, after it's diaphragm failed, with an NOS pump. Not knowing if the diaphragm in the NOS pump was alcohol compatible I replaced it's diaphragm with one designed for alcohol. The pump's casting is a bit rougher that I liked and it's original diaphragm was much thicker than the alcohol resistant diaphragm so I put a light coat of gas resistant RTV around the edge of the new diaphragm to help it seal against the rough casting. It seems likely the flexing of the diaphragm caused some of the excess RTV to detach. My hope when using the RTV was that gasoline/chemical resistant RTV would perform better than RTV historically does by NOT flaking off and plugging things up. I guess my hope was misplaced although the new pump diaphragm is still holding strong.
Last edited by Tiny; 09/19/2310:55 AM.
VCCA Member 43216 Save a life, adopt a senior shelter pet. 1938 HB Business Coupe 1953 210 Sedan
I am not a fan of the Parker designed valve but not for what most might suspect. The "needle" is aluminum and fits closer to the seat than most. Modern gas is much more prone to produce gums/varnishes. It takes a minute amount with lighter to stick them together. The heavier brass or stainless needles seem to be a little less prone to sticking. Sealing might be another story.
Chip - the aluminum is one feature I like; as it can not be magnatized as can the stainless needles. Once the stainless needle is magnatized, it will attract any rust particles from the fuel system, and leak.
The other feature I liked is that since there is no point sticking in the orifice, full flow is pretty much instantaneous with the valve off the seat. Keeps the bowl fuel level at a more constant height.
We never had issues with them sticking, but I can see as how it might be possible. Over time, guessing we would have used maybe 15,000~20,000 of them.
