Fuel starvation at full throttle, Carter W1 on 35 H8

bob wardbob ward Posts: 1,301Senior Contributor
Car starts and runs and idles well, and at up to 3/4 throttle there are no fuel starvation issues. But at full throttle, i.e. tackling a steep hill the fuel bowl quickly runs out of fuel, something must be happening within the carby that enables that to happen, the question is what?  
The fuel system is all new bar the carby, new tank, new filter, new lines, new electric pump.
I've flow tested the pump, the flow is more than adequate. It is supplying fuel at the carby at the rate of 750ml per minute which translates to 12.5 US gallons per hour.
I've blocked the return line seen in the photo to eliminate that from the variables.
Fuel tank is half full.
I've installed one of Wildrick's Daytona carb kits.
I've run out of ideas, any thoughts?


Comments

  • lostmindlostmind Posts: 1,414Expert Adviser
    Hang a 2 gallon fuel tank under the hood for gravity feed, direct to carb.
    This eliminates every thing but carb and ignition and exhaust system.
    Photo looks like 36 Hudson? Maybe a short in Distributor affected by advance,
    weak coil or condenser? , partially plugged exhaust?
    Some old pipes are double walled and collapse.
    Don't know about your gas over there , but it can effect where the float needs to be set.
    Sounds like you need a higher float setting if it turns out to be carb.
  • Park_WPark_W Posts: 2,536Senior Contributor
    Have you tried full throttle up the hill with the electric pump running?
  • tigermothtigermoth Posts: 448Expert Adviser
    The old adage is “90% of all carburetor issues are electrical “. may apply here. 

    Does the car start to pop and fart or just die? If it just dies that seems to indicate the trouble is less likely to be a fuel delivery issue.

    regards, Tom
  • bob wardbob ward Posts: 1,301Senior Contributor
    Thanks guys but the problem is definitely definitely that the float bowl is emptying itself at full throttle. 
    My test for this is that after I've been going up the local steep hill for a bit the engine starts running rough with typical fuel starvation symptoms. I pause for a bit to let the fuel pump refill the bowl and off we go again for a while. Rinse and repeat. Low gear and light throttle gets me up that hill (very slowly) without the engine misfiring.
    I'm clutching at straws here, the metering rod in the carby is a 75-107, is that the right rod?

  • GeoffGeoff Posts: 4,316Senior Contributor
    Bob, could be a heat problem?   do you have a heat shield between the carb and manifold, and a heat wrap around the fuel line. 
  • ToddhToddh Posts: 167Member
    You appear to have a Carter 310s which is correct for a 1935 Hudson 8.  You can confirm by checking the casting number on the bottom of the cast iron flange. It should be stamped “255” or just “55”.    Metering rod 75-107 is correct for that carburetor.  From the picture you posted you’re missing the fast idle linkage but that wouldn’t cause your fuel bowl to drain prematurely.  This model has a dash pot.  Did you replace the leather on the dash pot piston as well as on the accelerator pump?  Float level should be set to 3/8”. 
  • lostmindlostmind Posts: 1,414Expert Adviser
    Can you run it out of fuel without going up a hill? Maybe your pickup in the tank has a problem. Maybe a hole in the top side of fuel line or flex hose, or the hose collapses.
    I'd still start with a an auxiliary tank under the hood feeding the carb.
  • barrysweet52barrysweet52 Posts: 620Expert Adviser
    I have sent Bob a 1935 6cyl 309s carby and a metering rod guage. It may be helpful to read the carby notes and have one in the hand to understand better what is being read. Anyone know all the differences between a 309s and a 310s carby. Is it just the jets? 
  • ToddhToddh Posts: 167Member
    Metering rod, metering rod jet, pump jet and nozzle are all different.  
  • ToddhToddh Posts: 167Member
    A later Carter 330s or 414s are exact replacements for a 310s
  • ToddhToddh Posts: 167Member

  • barrysweet52barrysweet52 Posts: 620Expert Adviser
    Thanks Toddh, I will post Bob a carby stamped 71 tomorrow.
  • ToddhToddh Posts: 167Member
    Nice.  That’s a 330s
  • barrysweet52barrysweet52 Posts: 620Expert Adviser
    Thanks again. I have 20 I would like to identify and find new homes for in the next 3 weeks before I tidy up. Its unfortunate the cost of postage and freight Aust to the USA is expensive.  
  • bob wardbob ward Posts: 1,301Senior Contributor
    Thanks guys, lots of good info to work with, I'll report back.
    I suspect I need to unravel what 86 years and many pairs have hands have wrought.
  • Old Fogey UKOld Fogey UK Posts: 780Expert Adviser
    I gave up on my Carter and fitted a Daytona Zenith look-alike Universal - no further problems.
    As the Daytona looks exactly like a Zenith 228 (which was the official service substitute for the Carter W1), engine compartment originality issues are minimised.
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