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Old 09-11-2016, 09:02 AM   #1
Mini-Skoolie
 
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Chevy 366 carb adjustment

Hey all,

I'm a newbie and I just picked up a 1987 Bluebird 62 passenger bus in Oklahoma city. Will I've been making my way back to Virginia and it's been one thing after another.

I had the carb replaced with a rebuilt performance carb as I was able to ascertain that the distributor had been replaced and not all the barrels on the previous carb were opening so she would lose power if you dumped the throttle and you'd have to slow down to 15mph in order to get back on it.

Great so the new carb was awesome for about 300miles, power felt good, solid acceleration then randomly I started experiencing power loss, backfires and I couldn't maintain 40mph. Shut it down, pulled over everything looked fine. Started right back up but still didn't have the power it did before, I could get back to 50mph but it took forever... Worked fine for a while then again, back fires (acting like fuel is being dumped to the exhaust and detonating not necessarily combustion during exhaust stroke), and missing. And now I'm in Kentucky and I can barely make it up a hill.

This all seems like an adjustment issue, since I replaced the plugs, wires, air filter and fuel filter. So any tips on adjusting this thing? Or am I missing something else? It seems odd that the problem is intermittent and is fixed by turning off then back on.

As a side note, the drivers side rear brake locked up... Going to make a different post about that but since I have a limited set of tools I've got a mechanic coming out before I keep driving (it was glowing red and throwing sparks when I noticed it, so I slept in a dirt lot last night). So any general tips on that are appreciated, I'm definitely feeling a bit overwhelmed at the moment.

Thanks
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Old 09-11-2016, 09:20 AM   #2
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Fuel filter(s) there's likely more than one. There MAY be one in the tank, there MAY be one on the fuel line and MAY be one in the carb inlet.
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Old 09-12-2016, 11:17 AM   #3
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Quote:
Originally Posted by 2kool4skool View Post
Fuel filter(s) there's likely more than one. There MAY be one in the tank, there MAY be one on the fuel line and MAY be one in the carb inlet.
Thanks, I've done the fuel filters, going to check the timing today maybe it's a little too retarded.
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Old 09-12-2016, 11:36 AM   #4
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is it possible you have crossfire through the wires or a couple plugs fouling up with oil and so they refuse to fire? this would cause it to fee llike it has no power and would backfire out the exhaust.. im assuming its not puffing and popping under the hood but out the exhaust?

if its puffing and popping out under the hood you could have distributor springs sticking or if its an HEI style distributor the ignition module could be heating up and then going flakey but id look at the possibility of wires or maybe plugs fouling out ..

-Christopher
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Old 09-12-2016, 12:07 PM   #5
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Quote:
Originally Posted by snorris8236 View Post
Hey all,

This all seems like an adjustment issue, since I replaced the plugs, wires, air filter and fuel filter. So any tips on adjusting this thing? Or am I missing something else? It seems odd that the problem is intermittent and is fixed by turning off then back on.
This happens to me almost monthly. On my 366 I have 2 plugs that refuse to stay connected to the wires for long. Replaced the plugs, replaced the wires; but it keeps happening. Wrote it off as character.


Quote:
Originally Posted by snorris8236 View Post
As a side note, the drivers side rear brake locked up... Going to make a different post about that but since I have a limited set of tools I've got a mechanic coming out before I keep driving (it was glowing red and throwing sparks when I noticed it, so I slept in a dirt lot last night). So any general tips on that are appreciated, I'm definitely feeling a bit overwhelmed at the moment.

Thanks
Rear brakes can be a PIA if they lock-up. Mine did it and caught fire before I noticed it. I went the expensive route and replaced everything from the brake booster back. Two years later, my passenger side front went up in flames. This time I caught it in time so only needed to replace caliper, rotor, and pads: $230 parts, $210 labor.

Sorry to hear your luck is as bad as mine, but these old busses probably need everything overhauled just to be safe. Right now I'm searching in vain for a steering pump cap seal. The cap is no longer available and every material I try to use wastes away in no time.

Good luck with your repairs.
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Old 09-19-2016, 01:08 PM   #6
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Originally Posted by cadillackid View Post
is it possible you have crossfire through the wires or a couple plugs fouling up with oil and so they refuse to fire? this would cause it to fee llike it has no power and would backfire out the exhaust.. im assuming its not puffing and popping under the hood but out the exhaust?

if its puffing and popping out under the hood you could have distributor springs sticking or if its an HEI style distributor the ignition module could be heating up and then going flakey but id look at the possibility of wires or maybe plugs fouling out ..

-Christopher
I will troubleshoot this here shortly but you may be on to something. All the fuel filters are brand new and look great, the fuel pump seems to build pressure and I just adjusted the timing (though maybe a tad advanced now as its hard to start when hot, oops ;). Feels pretty good but still not as good as when I first replaced the air filter, plugs and wires (as I mentioned I did all that and the problem showed up about 200-300mi later I believe).

Not sure about the distributor style, is there a way I can tell? I only know that it is not the stock governed distributor, which is why I was able to easily throw a performance carb on there instead of the governed stock type. She starts right away, runs fine at idle its just the acceleration and power up hills is non-existant now. I don't get how for 200-300mi of that journey I had no problem cruising at 55mph now all of a sudden its a struggle.
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Old 09-19-2016, 01:10 PM   #7
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Quote:
Originally Posted by gizmoq View Post
This happens to me almost monthly. On my 366 I have 2 plugs that refuse to stay connected to the wires for long. Replaced the plugs, replaced the wires; but it keeps happening. Wrote it off as character.




Rear brakes can be a PIA if they lock-up. Mine did it and caught fire before I noticed it. I went the expensive route and replaced everything from the brake booster back. Two years later, my passenger side front went up in flames. This time I caught it in time so only needed to replace caliper, rotor, and pads: $230 parts, $210 labor.

Sorry to hear your luck is as bad as mine, but these old busses probably need everything overhauled just to be safe. Right now I'm searching in vain for a steering pump cap seal. The cap is no longer available and every material I try to use wastes away in no time.

Good luck with your repairs.
Yikes, we're in the process of doing the interior already and we plan to drive it out to Colorado in October... I would hate to be catching on fire and blowing tires during that trip, I think you just made a good case for replacing all the calipers etc. now. Going to take it a professional this week to get it inspected etc and he's been a family friend for a long time so hopefully he can help me get it sorted out to make this trek. I sure as hell don't want to be breaking down ever 200mi like I was on the way back from OKC last week.
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Old 09-19-2016, 01:46 PM   #8
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Quote:
Originally Posted by snorris8236 View Post
I will troubleshoot this here shortly but you may be on to something. All the fuel filters are brand new and look great, the fuel pump seems to build pressure and I just adjusted the timing (though maybe a tad advanced now as its hard to start when hot, oops ;). Feels pretty good but still not as good as when I first replaced the air filter, plugs and wires (as I mentioned I did all that and the problem showed up about 200-300mi later I believe).

Not sure about the distributor style, is there a way I can tell? I only know that it is not the stock governed distributor, which is why I was able to easily throw a performance carb on there instead of the governed stock type. She starts right away, runs fine at idle its just the acceleration and power up hills is non-existant now. I don't get how for 200-300mi of that journey I had no problem cruising at 55mph now all of a sudden its a struggle.
it could be that your fuel filters clogged up right away too.. there could be a lot of tank rust which would kill a fuel filter right away..

as for the distributor.. a typical HEI GMC style was the one with the coil in the cap... that was used for many years...

over-advanced timing will definitely cause hot starts and will make it ping like crazy on hard pulls..

on my old classic cars i used the clear inline fuel filter and a little gauge inline past the fuel pump.. when i had issues i could always look at those under the hood and see if the filter looked bad or if I was losing pressure past the filter..

if your carb or intake gasket is leaking you'll also lose power as it will Lean out on you.. a vacuum gauge on the manifold will help you to determine if you have massive vacuum leaks anywhere..

-Christopher
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Old 09-19-2016, 03:44 PM   #9
Mini-Skoolie
 
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Quote:
Originally Posted by cadillackid View Post
it could be that your fuel filters clogged up right away too.. there could be a lot of tank rust which would kill a fuel filter right away..

as for the distributor.. a typical HEI GMC style was the one with the coil in the cap... that was used for many years...

over-advanced timing will definitely cause hot starts and will make it ping like crazy on hard pulls..

on my old classic cars i used the clear inline fuel filter and a little gauge inline past the fuel pump.. when i had issues i could always look at those under the hood and see if the filter looked bad or if I was losing pressure past the filter..

if your carb or intake gasket is leaking you'll also lose power as it will Lean out on you.. a vacuum gauge on the manifold will help you to determine if you have massive vacuum leaks anywhere..

-Christopher
That's all great advice, I'll make sure we get a vac gauge on it and I'll check the filters again, there is a clear inline filter right by the car that still looks good and fuel color looks normal but the cost of replacing those again is so minuscule I'll probably change them again just to be safe since it was sitting in Oklahoma with a 1/2 tank of gas for "six weeks" (yeah right!) when I picked it up.
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Old 09-19-2016, 03:53 PM   #10
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Engine: DT360
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did you adjust the floats in the new carb when you put it on? trying to think of all the gotchas.. is it hitton on all 8 cylinders? if its idling does the engine shake? or if you go back to the exhaust and put your hand near the outlet is it smooth or a lot of rhythmic pulsing? trying to figure out if we just have a good old fashioned "miss" only hitting on 6 or 7 cylinders..

-Christopher
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