Yesterday the 26 coupe was cruising great: Went on an 8 mile ride and was doing 40, was pulling fairly big hills in 2nd gear without having to go down to first. Only problem was the continued dirty gas tank, and the float/valve sticking causing overflow issues. I HAD to take the carburetor apart, no choice since the float kept sticking. Now today I put everything back together, I also replaced the old bottom fuel line that feeds from the bottom of the filter I'm running to the carb. It now.....runs like total garbage. I think I have the needle turned out right: about 1 1/2 turns from bottomed out. Whenever I'm in 2nd it jumps: pull, weak, pull, weak, jumping like that. Can't even pull the small knoll up into the garage in 1st, let alone 2nd. I'm thinking maybe not enough fuel/filter issues? Motor does not sound super smooth as before but totally irregular. What's going on?
I had that as well, try opening the carb to check for fuel flow, check fuel valve, run and adjust the needle valve to find sweet spot.
I ran into an issue where I thought the carb adjustment was seated, but it actually had two more turns until seated- so it was running badly being too rich.
On one occasion I heard of a gas cap hole being plugged causing a problem. Just a thought.
Best of luck,
1. Dirty gas tank. Clean or replace it.
2. Fuel filter. Throw it away. Even with a clean gas tank, not enough fuel pressure to pass through the filter element quickly enough. With dirty gas: forget it.
Planning on ordering a 26/27 sediment bulb, what other things will I need? What type of fuel line should I use, etc.?
As to your needle valve. I have always found that while 1-1/2 turns is a good starting point, (no pun intended), it is usually way too much for general running. Once you have your other issue settled, start the car at 1-1/2 turns, let it idle & slowly lean out the mixture. When you hear the engine slow down a bit, richen it just enough to bring the rpms back. For my cars, it ends up being about 3/4 - 1 turn of the needle valve when all done. It will vary however, depending on the atmospheric temperature and engine temperature, with colder temps needing a slightly richer mixture, maybe 1/4 more open, till things warm up.
Buy the fuel line sold by the vendors.
Hmmm, looks like they don't sell it pre-formed. I'd use steel, if that's what you meant.
It comes with a bending template. It's easy to bend. I used one of my bending tools because I have one, but you could probably bend it by hand if you're careful not to kink it.
Yes, ditch the filter. The only kind you might get away with is the old glass bowl type with no filter element. But that just duplicates what the sediment bulb already does.
Fuel line: steel brake line from the local auto parts store.
When did you last check spark plug gap ???? Sometimes gap increases due to wear and heat.
,025" gap works for me.
Did someone "adjust" your coils without your knowledge ???
Fortunately no one's played with the coupe btu me. I think it's a myriad of issues.
1) The dirty gas tank. Probably impeding fuel flow from cowl tank into the line
2) The fuel filter, especially when getting dirty from the sediment, simply cannot keep up with the required gas amount
3) I had to pull and clean the carb, need to re-find the sweet spot it likes to run at
Oh, and not sure if this matters but I'm running 91 octane fuel since it's the only ethanol free stuff available around here. When the Coupe was running right I found it had better power with the ethane free fuel. I ordered new steel fuel line and 26/27 sediment bulb from Lang's today, as well as packing nuts and felt for the line. Any tips on purging the gas tank? I'd like to avoid removing it, but if I have to what do I do to remove the cowl tank in a 26 Coupe?
On the gas tank. You can put in clean fuel and drain it. Just put in about half gallon. You can run the fuel through a coffee filter which will clean out rust or dirt, and use the gas. However it will not clean out water. Sometimes when the car sets a while water will settle to the bottom of the tank. That water will come out first because it is at the bottom of the tank. The sediment bulb is good for draining out water because it is heavier than gas and settles to the bottom.
Other than that, you would need to remove the tank and take it to a radiator shop to have it "boiled out".
You can filter out the water in gas with a chamois cloth. I have done it many times.
The problems probably won't go away until the tank is cleaned/sealed. Until you get so tired of fighting it that that becomes your most palatable option, filters can get you going. Fuel filters are not all created equal and some will excessively restrict the flow but I have used WIX 33011 filters on my '26 coupe for a couple years now with no filter problems. My tank developed a lot of very fine rust residue that was happy to clog the sediment bowl and screen as well as the WIX filter. Cleaning helped for a while but I kept a spare filter with me at all times and got good at cleaning out the sediment bowl and screen. With enough frustration, I finally got lucky and found a good clean tank and replaced mine. I still use (and carry a spare) WIX filter.
My NH carb liked 1 1/2 turns when dead cold and then tapered down to 1 1/4 or a bit less once warmed up a bit.
Oh, the overflow tube needs to be removed from the tank before you try to take the tank out. It's a PITA to get out on a good day and when the tank can move around a bit it gets worse. The retaining bolt on mine had a straight slot for a screwdriver that was already pretty well stripped before I got to it. Nasty. Had to drill it out and the next owner of that tank will have some minor repairs to do.
When adjusting the mixture control following start up, I like to come at it this way. I first wind the needle in to lean off the mixture until the engine starts to miss. Then I wind it back out to make it richer until it starts to miss again. That gives me an indication of where the sweet spot is. Then I wind it back down again, approaching the sweet spot from the rich side. I figure I would rather be a little on the rich side than the lean side.
Allan from down under.
I've read all sorts of horror stories about old gas, stale gas, ethanol, etc., etc. But I run the cheapest grade, which around here is 10% ethanol. So far I've never had a problem with it.
I agree with Allan from down under. _Because the Model T's carburetor lacks an accelerator-pump, it will lean out on acceleration and possibly even stumble. You always want to be a tad rich to prevent that. _Put a dot on the edge of your mixture knob so you can keep track of your adjustments._A quarter turn can make a big difference.