DGTryon

I Agree with the comments on Balsa float but GM use nitrophyl floats in production carburetors for years and I have never heard of it sinking, It is a closed cell material and works great. I use it in all of my old cars. A couple of comments: 1. The mechanical level in the Buick spec only applies to cork floats. All other materials will be different. 2. The only way to get an accurate fuel level setting is using fuel in the bowl at the inlet pressure on the car (if a vacuum tank it is just the head of fuel - about 1/4 psi. I am using an electric pump at 1.5-2 psi. Any pressures over that risk flooding since the needle and seat/float system are not designed for higher pressures. 3. I put small white dot of paint on the inside of the bowl when it is off the cars that is 3/4" below the top of the bowl. When the car is running with the bowl cover off, you can see the actual fuel level. It should not be any higher that that. 4. Nitrophyl floats usually are not flat on the top when set correctly but as long as there is clearance around the float and clearance to the bowl cover, you should be good to go.

The "63" says it is definitely a Northway engine. The typical McLaughlin has a compete Buick chasssis and engine (30 & 40 series). This McLaughlin has nothing in common with Buick. I know of one in Ontario that is restored. D Tryon

The books that are available are all Buick for the engine and chassis. McLaughlin made the bodies, hence the dash is different, as are the wood top bows, top saddles and spare tire carrier.

Looks to me like one of the venturi's is installed upside down. I believe the smooth side should be on top. Minor issue though overall. The dashpot only affects the A/F mixture for about 0.5 sec on an acceleration, similar to the acceleration pump on modern carburetors. The backfire problem is more likely an air valve spring adjusted too low (lean or too far out). This is not a sensitive adjustment, move it 1/2 turn increments and see what happens. I had a 32-57 that ran great with the original Marvel.

Don't overlook spark timing. A retarded timing will case the same overheating issue. I have 3 of my old cars running up to 10 deg or more more advanced than spec. My 47 Pontiac would over heat at idle or in parades at very low speeds at 5- deg ambient. It now will idle forever and never overheat. Dramatic. Modern fuels with these low compression engines means the original spec is too low.

Basic physics involved here. A carb designed for 3-5 psi fuel inlet pressure has a much smaller needle seat than one running on a vacuum tank (about 0.5 psi). Hence the vacuum tank cannot supply the high fuel demands.

We have a big newsletter group that would be a big help to you. Contact me - Dean Tryon in NC, 919-562-4660 or dgtryon2516@gmail.com and I will fill you in. It focuses on teens Buicks with 200+ members asll over the world.

From several carbs I have, the air valve (plate) is flat and rotates freely on the pin. I do not believe the factory soldered the attachment screws but staked the back side typically. The spring locating pin is critical as others have said. I would be happy to discuss further your questions on electric pumps and adjustments. My number is in the newsletters.

Chris, If you send me your mailing address of full e-mail address, I can send you a newsletter we do for owners of 1915-18 Buick's and McLaughlin's. It is full of technical tips and interesting info and is pulished quarterly. Distribution is 175 members all over the world and has been going for over 13 years now. Cost is only $10 for 2 years for the e-mail version. I have an identical car to your 1916 so I'm sure we can help you. Dean Tryon - Editor DGTryon2516@gmail.com (NC)