55.2-59 Starting issue

[55Trucker]

I took my 55.2 3100 235 out for a 25 mile ride today, now that I've rebuilt the starter, put in a new fuel pump, rebuilt the carb, and put in new fuel lines. It ran great! With one exception: my wife and I made a stop on the way home for an ice cream, which took about 15 minutes. Then I had a dickens of a time getting it restarted, almost like it had no fuel. I had to crank it about 4 times, hitting the gas pedal a couple of times between cranks. It finally started.

Any ideas on what might have cause that? The tank is 3/4 full.

Thanks!

[mr48chev]

Remember, that it isn't fuel injected like your late models and it may want a shot of gas when you first start cranking it when it's been sitting for a few minutes.

I've had some with carbs that you hit the key when they are warm and they fire right up, I've had others that you had better hold your tongue in the correct spot in your mouth or so it seems. The 250 in my 48 would fire up without touching the pedal when it was warm and it wasn't bad if you set the choke when it was cold.

Do you have the idle speed set pretty low or is it at the prescribed rpm in the tune up specs? A low idle speed may not give you enough fuel air mix to start when you are cranking it.

I'm going to assume that you have the points adjusted correctly and have the timing adjusted correctly.

[1project2many]

You wouldn't believe it, but this is almost a textbook problem from the '70s. The manifold can get flooded with fuel or vapor, either due to a leaking fuel well or due to fuel ebaporating out of the carb and filling the manifold. It's likely to happen again since you haven't cured it. If, try pushing the accelerator slowly to the floor then cranking. That allows a rush of fresh air to mix with the fuel. Be ready for the truck to begin to roar to life so you can release the throttle. In time you will be able to start the engine without anyone knowing what's happening.

If that helps you could try mixing 4 ozs of Marvel Mystery Oil to each ten gallons of gas. The heavier hydrocarbons in MMO seem to help reduce the amount of fuel vaporized during hot soak.

[mr48chev]

Don't be afraid to experiment a bit with how you work the throttle when you go to start it. When you get it perfected so it starts right of again, it's time to take your wife for ice cream.

[Black_Sheep]

Modern oxygenated fuels are crap, the boiling point is in the same range as normal engine operation temperatures. When you shut an engine off it experiences "heat soak" which can evaporate the fuel out of the carb. If non-oxy fuel is available in your area give it a try, it's a simple change that may solve your problem.

[dsraven]

sometimes a fiber gasket under the carb will help insulate the engine heat from the carb so it doesn't evaporate. fuel boiling can start right after the engine is shut off with todays fuels. when it's hot try shutting it off and then put your head under the hood to see if you can hear the fuel percolating in the carb. when it evaps out of the carb it basically floods the engine so it can be hard to start right away after shut down. when it sits for a bit there is time to evaporate most of the fuel out of the carb. the fuel pump has to refill the float bowl so it can take some cranking to get that done if it has sat long enough to self clear the flooded condition. like someone said earlier, slowly put your foot to the floor to open the throttle without squirting fuel then crank it to allow ample air into the engine so hopefully clear the flooded condition. if you wanna check it, and youre by yourself (no wife watching, haha) you could take it out for a good hard run so it is hot then shut it off and come back in an hour. remove the air filter and look down the throat of the carb when you operate the throttle lever on the carb by hand there should be a squirt of fuel coming out of the accelerator pump that hits the edge of the throttle plate on the leading edge. no squirt means no fuel. it's because it evaporated from the heat transferred to the carb from the engine. the heat boiled the fuel off while it sat not running. a good reason to not start under the same circumstances at the ice cream shop.
dunno if that all makes sense. there are a few variables like how long it sat boiling the fuel out into the engine causing a flooded condition, did it self clear or not have time for that yet? is the carb only 1/2 full now, or less, so the reason to not start is low fuel level in the carb requiring a longer crank time? I would try a fiber or phenolic gasket under the carb to try stopping the heat transfer.

[mr48chev]

Good point there. An insulator would help keep the gas from boiling in the carb. If it happens again before you get it figured out you might just pour some ice water on the intake and fuel pump and see if it fires up.

[55Trucker]

Thank you everyone. And yes, this does make sense. Coincidentally I heard about a local marina that sells 93 octane non-ethanol gas. I went there yesterday and filled up two 5 gallon jugs with it to put into the truck in prep for Saturday's parade. Hopefully a fill up with that will help too.

[mr48chev]

Ethanol is the biggest joke played on car and truck owners besides those gas saver trinkets they used to sell in the back of magazines.

When I was in Poulsbo Wa on my sailboat a few years ago I met a gent with a 32 Packard roadster who was lugging 5 gallon gas cans down to the marina fuel dock to fill them and pack them back up an fill the car and then take two full ones when he headed home. Said ethanol had ruined two fuel pumps and some of the carb innards on it in the past. Here we have a Conoco station that sells ethanol free premium.

[55Trucker]

In another thread I recently posted that I had to replace my fuel pump twice in 3 years. I also had to rebuild my carb three times in the past 10. The powdery junk that was in the carb was unbelievable, and the little leather band on the accelerator pump was disintegrated. During this whole time I was adding ethanol stabilizer to the tank, but I'm not really sure whether it did any good, apparently not.

[mr48chev]

I think the stabilizer just keeps the ethanol from degrading as fast. Air as in a well vented system seems to be the main reason it goes bad in a hurry though.

I don't think the stabilizer has any effect on what it does to older carb, or fuel pump parts or hoses that aren't specifically made for it.

[1project2many]

Ethanol is corrosive. And it attracts water. Putting different metals together in a tank with water and ethanol invites galvanic corrosion. Brass floats in steel sending units get holes in them. Aluminum carburetor parts mixed with brass or steel fittings turn into white powder. Steel tanks with stainless fittings will rust. If we use E5 or E10 then we should expect to repair parts that used to last for years.

Oh, and FWIW, I had problems with stalling, stumbling, and hard starts due to fuel boiling in my truck until I switched it to EFI.