Technical Flathead First Start-up - Fuel in Oil!

The Power Valve is a way to provide more fuel into the main circuit under load.
If you look at the drawing above, there is a metering rod jet combo which limits the amount of fuel into the area marked Well. This sets the fuel volume allowed in the well, like a faucet turned partly on. The power valve when off is open, allowing more fuel into the well, but it doesn't get pulled into the throat. When running at idle (high vacuum), the PV is closed.
Only when there is low vacuum (high load) opening the PV AND good flow past the venturi that sucks fuel thru the main circuit will fuel flow.

 

Seems fuel is leaking past the outer seal of the PV. Filled bowl with just a tiny bit of fuel and tilted carb until PV was submerged. Noticed a drip on the outer edge of the PV almost immediately.

 

Fuel drop circled.

 

@zigster, smarter every day!

 

Well, holy hell! Gave the PV not even a 1/4 more turn, and it seems to have stopped leaking so far!

 

Well, that debunks the gas tank too high theory... with the PV situation corrected, that would be another test for another day.

 

I’m getting a beer or two to celebrate! No fuel on shop towel!

 

Gave the base a quick clean with the Dremel wire wheel to remove some of the corrosion. Back to re-assembly of carb.

 

Carb is back on intake. Added some fuel to the bowl and see if it drops over the next 30 mins.

 

Also noticed the new float needle is sticking a bit…

 

They can tend to do that, but remember, there is fluid under pressure behind it.
Notice the little tab in the middle of the arm? That should restrict the needle drop. EDIT: Float level! There should be spec for that. Just understand the float only drops to the bottom of the bowl not as far as shown.
That also is restricted by the arm touching the outside of the seat.
Lots of little fiddly bits!

 

Red is float drop limiter, Yellow is needle drop limiter.
EDIT: Yellow does not limit drop, it is float level setting!
The 2 needles look like they are different lengths and weights.
Recheck float adjustment if swapping.

 

Yeah. Needle on the left is the brand new one which is sticking. Have another on the right (not sure where it came from), and it doesn’t stick. Damn!

 

Yeah, will check specs again on float while I’m futzing around.

 

Speaking of PVs, found the other new one. It had the dreaded radius. Original one for comparison.

 

I was dealing with similar issues on my current project with a needle that looks identical. The needle would stick just slightly, but even the tiniest bit of pressure would dislodge it, and that fuel pump giving even 2 psi against the needle is more than enough to push it back out again, I don't think that's going to be an issue.

 

All I know is this engine better SING after all this fussing!
Keep at it, @Ziggster! We are all pulling for you.

 

I know it’s not equivalent, but when I blew on the inlet port it didn’t budge, so going with the other needle. It seats properly (at least when I try to blow through) it remains shut. We’ll see. So much freaking finicky crap to deal with.

 

Fuel level dropped a couple mm, but throat looks dry, so I’m calling it GTG, and will add the top, then hit the pistons with some oil.

 

Im glad you got it . The needle on the right is longer = heavier . I’ve found some new needles are a little on the large side , some 600 grit w&d on its edges fixes that problem, just a few seconds worth will do it .

 

Adjusted float. Was sitting too low (40 mm). Now at around 34.5 mm = 1.34” = 1 11/32”, which is what I used based on this.





Also took the edges off the float with some 400 grit as suggested. Helped, but still going with second needle.

 

Aww, he's using Metric on a flathead carb! I knew The Craft gif was trouble!

 

Removed plugs and dropped about a tbsp of oil down each plug hole. Then added a bit of oil with the weed sprayer under pressure. Next gave the crank two turns, then drained the oil. Will let it drain for about 45 mins, then refill with some more Lucus Hot Rod oil I had. Used some extra Mobil 1 5W-30 for the flush.

 

Haha! I was going to use this imperial square, but yeh? Other side is the same. Freaking useless…

 

Added 5 quarts of fresh Lucas 10W-30 Hot Rod oil. Added a bit more of the same oil with the weed sprayer. Cranked over by hand another two revelations with plugs out. All buttoned up and basically ready to get it back outside, but my kiddo just showed up with her new boyfriend. He’s willing to give a hand, so that’s a plus, and he knows cars. lol!

 

There's at least another set of eyes! Hope it all goes smooth and if not, the fixes are simple.
Can your kiddo video this? We gotta see you, I mean the engine in action!

 

Well after some hiccups, we finally got it started! Only was able to run it for 5 mins before it pegged the coolant gauge. Prior coolant was puking out of my overflow bottle for a while. Coolant gauge wasn’t registering for the longest time, and then it was pegged next time I looked at it. Rad felt cool, but both inlet and outlet coolant pipes were hot, so not sure what was going on. Rad fan came on at some point (set at 215F). I’m sure there was plenty of air in the system. I should have kept the rad cap off and watched the coolant level. Have vids but need to create a YT channel. Sounds awesome!

 

Was smoking a lot in the beginning but think a lot was paint cooking. Near the end there was not much smoke out of the DS collector, but the PS collector was still smoking a bit. Not sure what all that means. Re-torqued the intake, manifold, and head bolts. All were a bit loose. Also tightened up the clamps on the flex tubes as they were loose once again.

 

Wouldn’t start initially. Was cranking very slowly, so tried a 12V battery direct to the starter. Still nothing. Then checked voltage to dist coil. Was only 1V! Decided to run a wire direct from (+) on the 6V battery to the ballast resistor. Then tried starting it with the 6V battery, and she fired right up! Prior was only getting 4V to the ballast resistor. Might be my 100 yr old Bosch ign/light switch is not working properly.