difficult starting

[ChrisCoccia]

Way back when I first bought this truck, I had to give it a shot of ether to start it. Now after 3 years and completely dismantling and rebuilding it I am assembling and working the bugs out. It runs well, but I still have to give it a shot of ether to crank it. I also notice that the exhaust smells really rich. I started to try to adjust the mixture screw, but it stalled and I couldn't get it started again, and after a thirteen hour day at work I wasn't trying too hard eirher. I checked the screw when it was not running and it was only 1/2 turn from all the way in. Any thoughts?

[MBF]

Chris-that adjustment has to be made when the engine is up to operating temperature. I'd try 1 1/2 turns as a starting point. It sounds like you may have needle valve problems-either sticking, or maybe a heavy float or both. I had a /6 that was hard starting after sitting. Turned out the viton seat on the needle valve was causing it to hang in the seat. I've also had leaky floats allow raw gas to flood an engine. Keep messing with it you'll eventually find the culprit. Mike

[greg g]

the mixture screw won't affect starting, it's only purpose it so aloow more or less air into the idle mix. Once the throttle plate moves off idle it has no bearing on thow the engine runs. Does your oil smell like gas?? If so this indicated a flodding condition. this could be atributed to a mis adjusted float, or a float with a pin hole in it. This would mean the float bowl is over filling and allowig raw gas to run down the throat of the carb. Also could be an inefficient accelorator pump. With the aircleaner off you chould see a good spray of gas when you move the throttle linkage to WOT position from idle position.

And what procedure are you usning to start your engine?

For a cold start you should close the choke (if manual) Floor the pedal once, to set the high idle cam, then hold the pedal 1/3 to one half open while engaging the starter.

Fot a hot start, if it doesn't catch immediatly. The procedure is to hold the accelorator pedal at WOT while cranking the starter. This will clear a flooded condition that may be caused by fuel perculation or a stuck open eedle and seat valve, or a misadjusted float. May have found that setting the float a little lower (closes the needle valve earlier that spec) helps in adressing a hard hot start condition. Todays fuel brews also benifit from a bit of timing advance over factory spec. On my car I am runnign about 4 degrees before TDC instead of the TDC recommended by the manual. the oly time I prime or use starting fluid is on the initial crank up after winter storage.

[ChrisCoccia]

Today I cranked the truck and drove it for the first time around the block, about 1/4 mile. Other than the throttle sticking when depressed (like cruise control) it did ok. I tried adjusting the idle mix screw, and even when I turned the screw all the way in it didn't seem to affect the idle. When I got back from the trip I shut it off then tried to start it again and no dice. I will try again tomorrow using that starting protocol-thanks for the tip. I think that I need to rebuid the carb regardless.

[Merle Coggins]

I've found with my truck that I don't ususlly need much, if any, choke to start it up unless it's fairly cold outside. Then after I've been driving it and I go to restart it, I need to give it just a little throttle for it to start. I depress the throttle pedal slightly and pull out the "Throttle" cable to match. Then stomp on the starter and it'll fire right up. Then as soon as it starts I push the Throttle cable back in.

Merle

[grey beard]

When it is possible to turn the idle mixture screw - the one with the spring under the head that points toward the right side fender - all the way in and the engine keeps running the same, there is a big vacuum or air leak somewhere on the carb itself or underneath it in the intake manifold. JMHO

You didn't mention it, but when you say it starts hard, are you saying it cranks slowly or it cranks fine and will not fire up? This distinction is sorta' important when you want diagnostic help. If it cranks fine and just won't fire, we could be talking about either fuel or ignition system problems. Give us this information, and maybe we can be more helpful.

[ChrisCoccia]

It turns over fine but won't fire unless there is ether in there. With a shot of ether it fires and runs without even touching the pedal. That is a good point about the vacuum leak-I bought electric wipers, and when I had the manifold blasted I took the line out that went to the vacuum wipers before, and I just stuck a bolt in there a few turns temporarily when I first got it together, planning to get a brass plug to go in there. It may be leaking there. Plus the carb is always damp with gas on the outside, so those gaskets may be leaking air too. My truck doesn't have a vacuum advance on the distributor, so I don't have any other vacuum lines that I'm aware of.

[greg g]

The carb being damp on the outside is a good predicter of a float problem. So its either set to high or might have a pin hole in it. Carb should be for the most part Dry on the outside. Not 100% possible but shouldn't be any noticeable dampness. Is the area around the trottle shaft wet??? If so Id say you are flooding you engine, and emptying the float bowl at the same time. IF the float is hangning down due to a pin hole or not shutting off due to being misadjusted, the valve will open, the residual pressure in the fuel from the pump will over fill the float bowl flodding the engine, this will cycle till the residual pressure is gone, then the bowl will empty from evaporation.

So check your oil for gas smell, if present change it, then check the float, then check for air vacuum leaks on the engine side of the carb. Is the carb tight to the manifold and the manifold tight ot the engine? Have you done a vacuum gauge check of the engine while its idling?