I've read through many threads to try and answer what is wrong with my 1961 Olds 394 engine. I've done all the replacement parts, tuned and tested everything and still has the problem of it bogging down when taking off and now the engine is rocking at idle (like it has a miss fire).
The last thing done was from an "expert mechanic" who was recommended to me and he replaced the manifold gaskets, carb gasket and the turkey tray gasket. It was still doing it when I went to get the car back. He blamed the carburetor saying it was junk because he said he smoke tested it and smoke was coming out of everywhere on it (it's a brand new rochester correct for my car, not a rebuilt). I told him these carbs have vents in the gaskets.
I went home and tested everything over again (plugs, wires, dist cap, timing, dwell, adjusted mixture screws etc.) and found nothing wrong and tested the manifold and found it to still be leaking. I went back to the mechanic and of course he had every excuse in the book as to why he couldn't fix it and wouldn't give any money back etc. (I provided the gaskets I purchased from Fusick). I should have just done the job myself in the first place but I've never done one before and figured I'd give the job to an expert and it would be done correctly. Now I'm stuck fixing it myself and looking for some advise before I move forward. He did say he tested the manifold for leaks and found none (if I'm to believe that?).
Thanks in advance for any help.

 

Initial thoughts are carb related/vacuum leak. Really no such thing as a 'brand new correct' Rochester. Only new out there are knock offs from over seas.
All others are rebuild(most times messed up) unless you can find a unmolested original or find a reputable carb guy, your 'new' one might be hard to make work in the end without a bunch of fixing.

 

The carburetor is a brand new old stock. I rebuilt the original and the problem persisted and nothing changed with the replacement.

This is the carb I bought. If it's a fake it's a real good one. The person that sold it was or is selling rebuilt ones too.

 

I would get the intake checked for straightness. It may need milled to properly seal. Good luck.

 

Have you put a vacuum gage on it? If not that is the next thing I would do.

 

When I read rochester my brain went to Quadrajet.
Not much experience with these.
Even being a NOS, it would need some help in recalibrating for todays fuel and would guess some parts wont like todays alcohol content. Mainly accel pump. That could be causing bog. Look for good squirt of fuel when actuating throttle. Not sure but does this have vacuum advance on dist.?Would also check that weights and mechanism is free to move and if it has it vacuum advance canister in working.

 

See if you're dripping any fuel from the manual fuel pump. If the diaphragm inside has gone bad &/or the seam between the top & bottom has loosened, it can reduce fuel flow in particular right when you hit the pedal - as in a bog of more air than fuel is sent up the fuel line. When the fuel is flowing everything may or may not appear fine, sometimes when you hit the accelerator pedal you never get the bog other times you do. At any rate, see if you're leaking any fuel from the manual fuel pump. You checked to insure the in-line fuel filter is the correct filter and inserted in the correct orientation?

 

I agree with putting a vacuum gauge on it next before doing anything.

 

Thanks for the replies.
The problem I initially had/have was there when I bought the car. I found this site much later after owning the car and I had already done some things to try and fix the problem. I have read through the threads of people having a similar problem and tried the suggestions given to those people. You guys have been great in helping others so I don't want to be troubling anyone by having you repeat yourselves when you have already gone over it. So everyone knows where I'm at now here's the quick history.
I checked the car out before I bought it. The guy started it up from a cold start and it fired right up, no smoke, smooth quiet engine. I took it for a test drive and when I took off from a start it would fall on it's face and then go and smooth out. I know it's a 60 year old car and will probably need some tuning up and things will be worn out etc..
Changed fuel filter, didn't help.
Noticed strong gas smell when I would open the garage door from over night. Saw gas pooled up in a couple of places in front of carb on the manifold and the gaskets were wet. Rebuilt the carb, that didn't help. Adjusted the idle mixture screws with a vacuum gauge (reading was around 13").
The gas smell continued and could see the fuel pump was wet and dripping. Rebuilt the fuel pump, that didn't help. Replaced the vacuum lines from the fuel pump to the summer/heat ventilation system and the one going to the vacuum advance and the dash pot, made no change. Replaced the dash pot.
Replaced the spark plugs and did a compression test (got 178-181 readings) made no change. Replaced the points, condenser and cap adjusted dwell with a tuneup monitor and adjusted the timing, made no change. Changed spark plug wires, made no change. Moved the coil off the manifold and mounted it on the firewall, made no change then replaced it with another one, made no change. Replaced the Balast Resistor, made no change. Replaced the vacuum advance mechanism (which was shot and not working) made no change. Tested the heat riser and saw it was working properly. It was going to need a new muffler because it was shot so I cut it off along with the resonator andI ran it without them to see if maybe it was blocked and screwing with back pressure, made no difference.
The engine would get a little better with some things but it was getting worse now with idling, while it was cold and on high idle it would be smooth but as soon as it started warming up it would get rough like it was skipping.
Brought it to the mechanic that changed the manifold gaskets and he demonstrated there was an air leak through the manifold using carb cleaner, when he sprayed it it would smooth out. As I said when I picked it up he said the carb was junk and that was why it was still running bad. Before I go through rebuilding the new one I tested everything else again in case I over looked something or maybe a part I replaced was no good. Every thing tested good except the fuel pump. I could hear a clicking noise coming from it when I was near it and the noise matched the skip. I took it off and saw I had pinched the diaphragm where the vacuum part is. I rebuilt it again in case maybe something else let go. Everything was good so I put it back together correctly and back on the car. I thought I finally found the problem and was so disappointed when that wasn't it. On the positive of that It did help a little and glad I found it now rather than later and the vacuum increased to 15".
I brought it to the local car show and while there asked some of the old timers if they could help me figure out what is wrong. One guy tweaked the mixture screws and when he sprayed some carb cleaner around the intake manifold in one area the engine leveled out smooth. He tightened some of the nuts about a 1/4 of a turn but it didn't really help all that much.
I went back to the guy who did the gaskets to have him correct his work and that's when he started making up excuses and I caught him lying. He said he did notice a little bit of smoke coming out from a couple of areas but it stopped when he torqued it down some more. Then he said he even tried doubling the gaskets but that didn't change anything (he only had one set of gaskets). Then he said he didn't want to send them out to be machined because that could change the angle and size and they might not seat right after and leak. Then he said he added silicone. Then he said I'm better off getting an after market aluminum manifold because they are more forgiving when they are tightened down. Then he said there's nothing else he can do for me.
At the moment I really can't do anything because I'm low in the cash department, I have a fixed income on social security. This just cost me nearly $600. I need to pay down the cards some first.
I have a few questions.
If this manifold turns out to be cracked can it be welded or should I get another one? And if I replace it do any of you have one for sale and how much? Will changing with another one still have to be milled down? Is there a chance I would be able to reuse the new gaskets that were just put on? If not is there someone selling them cheaper than Fusick and would they be as good? Would using a thicker gasket help and are there any available for this engine? And is there an aluminum manifold available for this engine, I'd rather keep it original if I can?
Lastly, should I just put the old carb back on seeing I had rebuilt it with the newer gaskets?

Thanks for your help.

 

I think the only aluminum manifolds for this engine will be 3x2 manifolds and they would be pretty expensive and you probably don't want to do there. Depending on where the crack might be would probably determine if it can be welded. Have you checked the hose(s) at the gas tank. These can crack with age and start pulling air in. This is one of those things that is often overlooked.

 

Just last month I took the gas tank out to have a repair for a leak around the filler neck and saw the line is in good shape and the ones in the engine compartment are too.
But that's a good idea because I wouldn't have thought of that.

 

It's not clear, but it sounds like the intake manifold is the problem. You can have yours removed and have it checked both at the head surfaces and at the carb. If it's not flat have them machine it. You will need to reinstall with new gaskets. Or you can buy a used one and have it checked by a machine shop before it's installed, at least that way you won't have any downtime with the car.

 

Thank you for your input. Redoing the manifold gaskets is going to be the next step.

I'll update the thread when it gets done. Hopefully that fixes it.

Thank you everyone for your feedback.

 

If the gasket mating surfaces are warped (not flat) changing the gasket wont help and is a waste of time and money. When you have the manifold out, take it to a machine shop to check. If they are flat they won't charge you very much to check. If they are warped, you need to have the machine shop mill the intake. If they are warped really badly, you may need to get a replacement intake manifold. Gaskets can only deal with minimal warping.

 

The shop that did the gaskets should have done that in the first place and I wouldn't be going through this now.
I spoke to a machine shop today and he said it'll be around $150-200 and he'll have it done in a couple of days after I drop it off. Who knows, it might not need any shaving. I saw a puddle of antifreeze under the car today, it looks like it's leaking from the goose neck. The mechanic never changed it when he did the job.

 

I noticed yesterday that there's fresh oil on the rim of the fuel pump. It started to appear a couple of days after I had reinstalled it. Is that normal?

 

Have you checked timing chain slack? Hope you find the problem.

 

Even though the carb has been rebuilt if you still have gas pooling on the manifold or a it is still wet around the accelerator pump or you can still smell gas like you did the float level may not be set accurately and the float may be setting too high in the bowl. This may all be moot if I missed that you have changed the carb since then. You mentioned an NOS carb and not sure if that is different or the one that was rebuilt but anyway just trying to help out. Trying to adjust idle mixture or expecting correct accelerator pump function when the float level is wrong is a loosing endeavor.

 

Love Eric. Super smart mechanic. I've watched many of his videos.
A mechanic checked this already and he said it's ok, but the way everything is going I'm going to do the test myself to make sure.
Thank you and appreciate the video.

 

Appreciate the reply. I did replace the carb and there isn't any leaks from this one. What I mentioned was the mechanic that did the manifold gaskets blamed the new carburetor for his failed(?) repair. As of right now I'm going to take the advise of some who replied here and do those suggestions first before I tackle redoing the manifold. I'm going to go back to the beginning and do some things I skipped over thinking it didn't need it and or trying to save money.
I have to rebuild the fuel pump again because I've got oil leaking out of it from me damaging the seal around the rod on the diaphragm.
I had the fuel tank out to have a leak fixed but I didn't bother to replace the 60 yr old rubber lines, blow out the steel line or check the condition of the sending unit and test the pressure. I won't do anything more until I get that done.

 

I went to do some of the tests today. When I opened the garage door I could smell gas and discovered the fuel tank is leaking from around the sending unit. I can''t find a good mechanic lol. The mechanic did find it was leaking around the filler neck and repaired that so I guess he didn't pressure test it after.
Not to be discouraged, I did the test for the timing chain and it's good.
I checked the flow from the fuel pump and I'm not sure if the result is good or bad. I cranked it over a few times and at the length of time it would take to fill the carb and there wasn't very much gas in the bottle after. I used a juice bottle around four inch wide and there was about half an inch of gas in it. I spoke to the guy at the place where I got the rebuild kit from about the oil coming out of the pump and he said it's from the oil seal that I didn't lube when I was assembling it and that tore it. This was the first time I've rebuilt one of these. I hope he'll sell me just the seal.
I also looked down into the carb and saw two steady streams of gas and it came out as soon as I moved the throttle.

 

I've got some updates to my car problem. I took all your advise and this is where I'm at.
I successfully rebuilt the fuel pump, Then and Now sent me a couple of oil seals for nothing and that fixed it. A few days later when I went to the garage I got hit in the face with the smell of gas again. This time it was from the gas tank leaking around the sending unit. I couldn't find a replacement gasket and ended up making my own. While I had the tank out I replaced the 'sock filter' that I got from Fusick. I replaced the rubber line near the tank and the one in the engine bay going to the fuel pump and blew out the steel line with compressed air. I replaced the fuel filter in the glass bowl and replaced the rubber lines from the fuel pump to the fuel filter and from the fuel filter to the carburetor with steel lines. After starting it up it was running the same as before. I put my old carb back on and it ran smooth for just a few seconds and stalled and when I looked under the hood gas was pouring out from the carb. I think the needle was stuck or floats from sitting around. I took it apart again and remeasured the specs on the floats to be sure and when I put it back on the car the car ran pretty smooth. I took it for a ride and it was a lot better but if I put my foot into it it would hesitate and buck so I think there is still something wrong with the carb.
I ordered a rebuild kit for the new carb and rebuilt that one and when I put it on the car today the car ran the same way when it was on it before. I also checked the fuel pressure today and it was a steady 5 lbs.

I'm at a loss for ideas.
There were two differences between the carbs. The new one has the bowl vent for a car with a/c and I changed the base gasket with the one from the rebuild kit. The other one was twice as thick and it came from Fusick. I made sure I matched up the gaskets when I did the rebuild.