[Pontiac62]

About a month ago I had a flooding problem. I got new needles, seats and floats.
Then when I started to drive it again, it wasn't running quite right, This time I discovered that the accelerator pump rod had gotten bent, was too short, and was holding the throttle plates open. Got that fixed, and it seemed to be OK.

So yesterday, we went to a car show. Ran OK until we got to the show and had to move the car. It did not want to start. was obviously was way too rich. After sitting all day it started fine, and we drove home. Got in the garage, and the gas smell was terrible. Popped the hood, and found gas leaking out of the top of the front carburetor.
So what am I missing. I set the floats according to the specs in the service manual. Are those still correct? Anyone have any Ideas, as I'm starting to get frustrated? Thanks for any suggestions.
Les

BTW, Happy Father's Day. I'll not be back here today

[Tom Vaught]

99% of the time if you have flooding of any carb, you have either the float level (float) set wrong (not likely as you drove the car to the show, or a needle and seat issue which is hanging up the float (not closing the needle) and then you get flooding.

So tomorrow when you read this add some additional info. Which carb is the problem?

Have you tried to isolate the problem by removing the fuel to the other two carbs:
Remove the fuel line from the filter connection and run a hose from it to only the center carb.
You will need a piece of flared tubing the same size as the aluminum fuel line to make the connection.

Put solid (no holes) paper gaskets under the end carb or remove them and use regular gaskets and block off plates.

You are trying the find the bad character in the mix. If the issue is easily identified as one carb, take that carb apart and find the problem.

Fix it and enjoy the summer.

Tom V.

[Dick Boneske]

As Tom said, you need to determine which carb is at fault. No need for extra work, however. Just look in the three carb throats after shutting off the engine when you're experiencing the problem. With a rich condition, one of them will be wet inside the airhorn. Take that carb apart and fix it.

[Jack Gifford]

Originally Posted by Pontiac62

... found gas leaking out of the top of the front carburetor...

He said...

[Kenth]

At times when i still used the mechanical fuel pump on my 1966 Tripower, one or all carbs were leaking fuel in about 10 minutes after shut off.
Turned out i was having 21psi in the fuel line between pump check valve and carbs inlet valves after shut off due to expanding fuel in line due to engine heat.
I then (25+ years ago) replaced the mech fuel pump with an electric Carter P4070 5psi pump (w/o check-valve) allowing fuel to return instead of over-pressurize fuel in line at shut off.
No issues of the sort since.
HTH

[Tom Vaught]

With any electric fuel pump, I always have a small bleed circuit .030" that will relieve the fuel line pressure fairly quickly.

But I have always run a return style fuel system back to the tank. At one time, I could find the fuel filters that had the return nipple on the filter can. Now I just use a custom fuel block with the orifice built into one leg of the "Y".

Tom V.

[Pontiac62]

I appreciate all your suggestions. I will be taking the front carb apart, but it may be a few days. We are in day 2 of a week of entertaining two of our pre-teen granddaughters.
Thanks, Les

[pfilean]

After I bought my 61 I noticed the front carb was leaking extra fuel into the throat. Did a little investigating and found the PO had not tightened the seat into the casting. Was bleeding around the seat gasket. A little turn of the screw driver and everything is good.

[Pontiac62]

Finally got some time today. Took the top off the front carb. The float level and drop were right on the settings. Took the float and the seat out. Everything appeared to be right. Put it back together and started it up and it seemed to run OK. Shut it off and immediately restarted, no problem. Shut it off and watched the pressure gauge. It slowly bled off to Zero psi. It took about two minutes. Tried again to restart and in started very hard. Looked down into the throttle bores, and found gasoline sitting on both the front and rear carb throttle plates.
So obviously gas is leaking into the end carbs after shut-off.(and whenever it's running) This is the float that I'm using in the end carbs with no clip, as per Mike Wasson.
The seats are tight, so it would appear that the leaks have to be at the needle and seat contact point. Are the settings listed in the Service Manual no longer correct with the composite floats? What now?
Thanks, Les

[Kenth]

Are you using the original style .086" seat inlet valves in end carbs?
I would not use anything else.
FWIW

[footjoy]

I had the float was sticking problem and talked to a Pontiac guy at a car show. he told me he used Lucas gas treatment to add a little lubrication to the fuel. I started using it and never had that problem again. I know it sounds too .

Good luck

Greg

[Tom Vaught]

Originally Posted by footjoy

I had the float was sticking problem and talked to a Pontiac guy at a car show. he told me he used Lucas gas treatment to add a little lubrication to the fuel. I started using it and never had that problem again. I know it sounds too .

Good luck

Greg

I believe what you have posted.
Sometimes the surface that the needle rides on gets kind of rough.

I polish the contact area on both the needle and the float. Never had one stick after I started doing that about 30 years ago.
Just takes some time but a lot less time vs being stuck on the side of the road.

Tom V.

[dlloyd]

You might want to try a fuel regulator and set it to 4 PSI.
I was having flooding issues occasionally with my Tripower but after installing a fuel regulator I have had no problems.

[My64GTO]

Originally Posted by Pontiac62

Finally got some time today. Took the top off the front carb. The float level and drop were right on the settings. Took the float and the seat out. Everything appeared to be right. Put it back together and started it up and it seemed to run OK. Shut it off and immediately restarted, no problem. Shut it off and watched the pressure gauge. It slowly bled off to Zero psi. It took about two minutes. Tried again to restart and in started very hard. Looked down into the throttle bores, and found gasoline sitting on both the front and rear carb throttle plates.
So obviously gas is leaking into the end carbs after shut-off.(and whenever it's running) This is the float that I'm using in the end carbs with no clip, as per Mike Wasson.
The seats are tight, so it would appear that the leaks have to be at the needle and seat contact point. Are the settings listed in the Service Manual no longer correct with the composite floats? What now?
Thanks, Les

Mike did my carbs too. Actually he did them twice; once about 12 years ago and the center carb again this year.
I had a lot of flooding problems last year and attributed it to the gas and length of time since the last rebuild. I also ended up putting in a fuel regulator per Mike's suggestion to stop the flooding issues.
When Mike did mine originally 12 years ago he used a checkball type of needle/seat called a "Grose Jet" as opposed to the traditional kind.

Grose Jets eliminate the needle/seat issues that commonly happen, (although you will find pro/cons about them too). They are also harder to get and a bit pricey ($16 each), but you can still find the reproductions on Mike's site.

I swear by them and had Mike keep the old one in my carb as opposed to the new style needle/seat he is using today. The pic attached is from Mike's site where you will see the Grose Jet (L) and new style needle/seat (R) side by side.It might be worth buying a couple to see if it resolves your issue. Since they are getting harder to find, I bought one just to have as a spare.

[Pontiac62]

Originally Posted by Kenth

Are you using the original style .086" seat inlet valves in end carbs?
I would not use anything else.
FWIW

Apparently they are .119" orifice. Where do you get the .086"

[carbking]

You have a political problem, not a carburetor problem! Politicians for the last umpteen years have determined we "need" ethanol, butane, and a host of other chemicals in the fuel (which used to be gasoline).

Re-read Kenth's post (#5). Note his comment about pressure.

Then check this link: http://www.thecarburetorshop.com/Tro...m#Hardstarthot

I know it kills authenticity, but if you cut in a return line right at the 4-way (the return line needs to dump into the top of the fuel tank), your problem will disappear.

With the 1964~1966 tripower, normally it will be the front carb leaking, as that is the point of maximum pressure. Since the front carb leaks off the pressure, the other carbs don't leak. Lower the fuel level in the front carburetor, and you can transfer the leak to one of the other carburetors.

Jon.

[Dick Boneske]

I have restored over a hundred Tripowers. The conventional needle/seats are not reliable. Upon the initial startup, typically at least one of the carbs floods. To fix it, sometimes a few sharp taps on the fuel inlet area with a plastic screwdriver handle will cure the problem, but sometimes you need to take the airhorn off the carb to clean up the needle/seat. Most often the problem is a small speck of dirt, but sometimes the needle sticks in the seat so the float can't overcome it.

I've stated this before, but for the past five years I've used TOMCO needle/seat assemblies. These assemblies have a flat disc that seals the orifice. I've had ZERO failures upon startup or after the car is being driven. These needle seat assemblies are TOMCO part number 555. If you want one or three, PM me and I'll send what you need. There are people on this forum who disagree with the TOMCO units, but I believe they've never tried the actual TOMCO brand needle/seats.

[Jack Gifford]

I've had plenty of needle/seat reliability problems since the old Wisconsin V4 on our combine about 1950. But for whatever reason, the Tri-Power I bought in '61 (SD aluminum) still has the original seats and floats and has NEVER had any such problem. Yeah, I've probably replaced the neoprene-tipped needles at times, but that's to be expected over almost 60 years. I've got tens of thousands of miles on it- presently on the Pontiac/GMC that I drive almost daily in the summers- turn the key and go, almost never open the hood.

My point is- there can't be anything inherently wrong with the design.

On the flip side- the needle and seat of my 7HP Kohler are so troublesome that I may give the Tomco parts a try.

[carbking]

Dick - I have not seen one of the Tomco fuel valve in years, so do not know what they are currently selling.

Their valve used to be:

(1) a brass seat EDIT: the brass seat had an inverted flare for sealing
(2) an aluminum plunger, rounded on both ends
(3) a neopreme washer encapsulated in an aluminum wafer

When I was still restoring carburetors, I can remember at least two carbs using these valves that came in with "severe flooding issues". Both had the wafer lodged close to vertical between the seat and the plunger, allowing continuous full fuel flow.

I promise - you will NEVER see one of these in one of our rebuilding kits.

So we will have to agree to disagree.

http://www.thecarburetorshop.com/Fuel_valves.htm

Jon.

[61-63]

I've used quite a number of the wafer type needle and seat assemblies from Daytona Parts over the years with no problems, on both tripowers and others, primarily AFBs. They are proprietary and are designed in such a way that it is mechanically impossible for the wafer to turn sideways. The only problem with them is that the seats are only .085, which isn't large enough for the fuel pump to keep up with the engine all the way through the quarter mile in a large cubic inch Pontiac mounting dual quad AFBs, which is the main thing I do. I used to ask customers if they were going to race their car, and if so, installed Edelbrock high flow needles and seats which have .110 seats. Of late I've just installed the high flow sets in all of the carbs I've done. The main thing I have found when people have sent me a carb that is causing flooding problems, or come by to have me look at it, is that the float level has been set too high. Float level is supposed to be set where the fuel is right on the cusp of overflow in the boosters, and it doesn't take but a smidgen of setting it/them too high to result in flooding.