Need Help with a 305 Chevy
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Need Help with a 305 Chevy
Yes, I bought a Chevy 305, by accident, sort of.
It's in my boat, a 1979 Chevy 305 185 hp with a Rochester 2 barrel & vacuum choke - The boat anchor of boat engines...
But the old gent who had it before me took meticulous care of it and WHEN IT FINALLY STARTS it purrs like a kitten.
When it's warm it starts with a touch of the key. No cough, sputter, nothing. Touch the key and it's purring away at about 800 rpm. Hit the throttle and it runs up smooth and levels out at about 4800.
When it's cold, you can plead, beg, pray, swear or whatever else you want to try and maybe if it feels like it it might stumble out of bed like an old drunk and think about starting the day. Give a minute or two to stumble along and it will level out and all is good.
I suspect the vacuum choke, but now it's warm and I have to wait for it to cool down before it will act up again.
Any input is appreciated.
It's in my boat, a 1979 Chevy 305 185 hp with a Rochester 2 barrel & vacuum choke - The boat anchor of boat engines...
But the old gent who had it before me took meticulous care of it and WHEN IT FINALLY STARTS it purrs like a kitten.
When it's warm it starts with a touch of the key. No cough, sputter, nothing. Touch the key and it's purring away at about 800 rpm. Hit the throttle and it runs up smooth and levels out at about 4800.
When it's cold, you can plead, beg, pray, swear or whatever else you want to try and maybe if it feels like it it might stumble out of bed like an old drunk and think about starting the day. Give a minute or two to stumble along and it will level out and all is good.
I suspect the vacuum choke, but now it's warm and I have to wait for it to cool down before it will act up again.
Any input is appreciated.
Fleet Owner
Joined: Aug 2010
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From: Reynoldsburg, Ohio
I'd start checking the plugs, wires, cap, rotor first even though 85E150 is also possibly onto something as well.
I have an '84 Pontiac Parisienne (think Caprice) with the same motor but the E Quadr-Jet carb. If I don't set the choke by pushing the gas pedal to the floor once on colder days it acts much the same as you describe. Once warm it purrs like expected.
Can't be too serious of a problem since it seems to run and start so well the other times.
I have an '84 Pontiac Parisienne (think Caprice) with the same motor but the E Quadr-Jet carb. If I don't set the choke by pushing the gas pedal to the floor once on colder days it acts much the same as you describe. Once warm it purrs like expected.
Can't be too serious of a problem since it seems to run and start so well the other times.
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It's a points ignition that is soon to be changed out for electronic. I have the new plugs and I'll probably get those in today.
This is my first experience with a vacuum choke so I don't really know how to test them, late last night I did discover that the choke vacuum line is showing some cracks so that's a good place to start. It should be completely closed for starting cold?
It has a clear fuel line (clear as in see-through) that does not appear to be losing its prime, although that is exactly how it acts. Hm, fuel pump diaphragm.
I'm sure once I find it it will be one of those "well that was obvious" moments.
This is my first experience with a vacuum choke so I don't really know how to test them, late last night I did discover that the choke vacuum line is showing some cracks so that's a good place to start. It should be completely closed for starting cold?
It has a clear fuel line (clear as in see-through) that does not appear to be losing its prime, although that is exactly how it acts. Hm, fuel pump diaphragm.
I'm sure once I find it it will be one of those "well that was obvious" moments.
Hotshot
Joined: Feb 2004
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From: Marengo, Iowa
This is important. If you are just climbing in and cranking like you would an injected, you will always have this issue. The old carbs need to be pumped. This does 2 things, closes the choke, and also squirts a little gas into the throttle body area to give the motor something to fire on. Injection systems do all that kind of thing automatically. What the choke does in essence is raise the vacuum in the area between the throttle plate and choke plate, which helps it draw fuel out of the fuel bowl. The accelerator pump squirts a little gas onto the throttle plate so that there is a little fuel available to fire on. If you do not move the throttle when you first try to fire, the accelerator pump does not get moved, so no gas to start with.
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My brother's first car in high school would flood if you looked at it wrong so maybe I'm a little gun shy that way.
I've been pumping it once, but maybe that's not enough. This morning on a cold engine it cranked maybe twice and fired right up, so that points to a "time between starts" issue more than a "warm or cold issue," in my mind.
Maybe I just need to pump it 3 or 4 times, leave it to me to make it complicated.
I've been pumping it once, but maybe that's not enough. This morning on a cold engine it cranked maybe twice and fired right up, so that points to a "time between starts" issue more than a "warm or cold issue," in my mind.
Maybe I just need to pump it 3 or 4 times, leave it to me to make it complicated.
Hotshot
Joined: Feb 2004
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From: Marengo, Iowa
Some carbs like more than one. It is possible to bleed the gas back too if left for long periods. You should be able to look inside the carb throttle body and see the gas squirt when you work the throttle.
Cargo Master
Joined: Dec 2007
Posts: 2,196
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From: Carstairs Alberta
as far as it being a boat anchor, in cars the 305 had a reputation for the cam lobes wearing out. might not hurt to check lift. a larger cfm carb and bigger cam might give it more go if you match the prop to the mods. never going to have BB bottom end though
in my trans am the engine was susceptible to running cold with a weak thermostat and fouling the plugs enough to reduce starting and running performance. With as many as are out there you should be able to find a nice HEI distributor with a good timing curve. It should help starting (somewhat) and maybe overall as well
in my trans am the engine was susceptible to running cold with a weak thermostat and fouling the plugs enough to reduce starting and running performance. With as many as are out there you should be able to find a nice HEI distributor with a good timing curve. It should help starting (somewhat) and maybe overall as well
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Joined: Jul 2011
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From: Nanaimo BC
Be carefull with what you use for an electronic distributor. You need one without vac advance and the timing curve needs to be different than for your typical street car.
You need 14* initial with a slow curve that's all in (30*) by 3200 rpm. Too much advance will melt pistons.
If you don't like the way the choke works just put a manual choke on it.
You need 14* initial with a slow curve that's all in (30*) by 3200 rpm. Too much advance will melt pistons.
If you don't like the way the choke works just put a manual choke on it.
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Good to know, thank you.
Thought about that, I'm a big fan of manual chokes, nothing like something that just works all the time.
If you don't like the way the choke works just put a manual choke on it.
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