Q for the weber peeps

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danzo
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Q for the weber peeps

Post by danzo »

As you may remember I slapped in the 32/36 about 8 months ago but I've been having some driveability issues. Cold starts are OK, as are warm starts after sitting just a coupla minutes. Curiously if I restart the car after warm and sitting for 10-30 minutes it takes alot of cranking, then hesitates on accelleration for the next few minutes. The choke is working properly. Gas mileage is less than expected at about 27mpg mostly city, and I drive with a very light foot.

During the hot summer months I could smell gas boiling out of the carb jets, and I could hear it perculating. Indeed there was liquid fuel in the intake when the carb cover was removed. My laser pyrometer would read a high temp of about 160 after shutdown. Then I thought maybe the fuel was not returning to the tank since my fuel pressure gauge would read about 2psi for awhile after shutdown. So I removed the return line from the fuel pump and had a tough time blowing into it (even with return line disconnected at the tank), but I could suck on it much easier. Make your own jokes. Is there a check valve somewhere? I didn't see one in the FSM.

Then today I started thinking I did the carb install wrong and reread some old weber install posts. I realized I might have left out a step or two. I did the PCV to EGR port mod and removed/capped the dizzy ports (vac advance is toast). However I left the charcoal canistor in no man's land with the lines to/from it hooked to nothing. So today I hooked the VSV to the ported vac on the carb (previously capped), and the outer vent control valve (OVCV) is still 'vented' into nothingness. I haven't driven it like this yet. Is this OK, i.e should OVCV be hooked to something? Did I install something else wrong?

As always thanks in advance. I'm looking forward to getting 'er running properly.
It's a scientific fact that in a twin engine aircraft, when one engine fails there is always enough power in the remaining engine to make it all the way to the crash site.
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ARCHINSTL
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Re: Q for the weber peeps

Post by ARCHINSTL »

Keeping in mind that St. Louis, despite our record prolonged heat wave this Summer is NOWHERE near the heat in Lewisville/Dallas...
I have had a bit of cranking (like 4-5 seconds) on hot restarts after sitting a bit just like you. This is in cold weather as well, but is more noticeable in hot. I don't get any hesitation, though.
My MPG is about the same as with the OE carb at around 27-30 combined - a little disappointing, but with the OE hesitation and other BS with the Aisan carb disappearing - I accept it gratefully.
I can't smell any gas percolating, although there are some fuel stains around the adapter and OE heat shield.
I just blocked off the EGR port and used the phenolic plate OE connection for the PCV.
The fuel pump was new with the Weber in '08 - no leaks there. I did install the gauge and regulator like splatterdog's installation.
No emission stuff is hooked up - in fact, all has been removed. The canister is still there with the hoses vented to nothing (in fact, I'm going to remove it this weekend and just route the tank tube to below the car - or maybe to the Redline filter - undecided).
I didn't change jets or anything like that - whatever the vendor supplied - supposed to be correct for our elevation of 600', but really dunno.
Ignition is advanced to 10°, as recommended.
My manifold vac is hooked to the front dist tube and the carb port to the lower dist tube.
Tom M.
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Petros
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Re: Q for the weber peeps

Post by Petros »

Danzo,

Your description of starting problems are common with all carbs, my stock carb acts the same way on very hot days. I think it is the fuel vaporizing in the line/carb from heat soak off the exhaust manifold. When it is cold the fuel stays liquid, as it does after a short shut down. When the car is moving air is circulating and cooler fuel is being pumped into the carb. When everything stops the carb and fuel line absorb a lot heat from the exhaust manifold and engine, causing vapor lock.

If you still have the heat shield and plastic carb insulator you might install it. I put foil around my fuel lines to try and help keep the heat off of it (the line runs right over the top of the exhaust manifold).

I am not familiar enough with the weber to help you with it (it has been many years since I have worked on them), but it seems to me 27 mpg is not bad for city driving.

This is one reason I want to switch to EFI, this problem goes away.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
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teranfirbt
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Re: Q for the weber peeps

Post by teranfirbt »

My car acts the same. On mine if you go wide open after a couple cranks it starts right up. Instead of the stock carb separator, go get a carb gasket for a 70's 2.3 litre Pinto. Motorcraft licensed the 32/36 and the gasket is about 1/2" thick. I can put my hand directly on the carb after driving hard for 150 miles and it's touchable. Without the Pinto gasket I could barely touch the carb.
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Re: Q for the weber peeps

Post by ARCHINSTL »

As always, a logical explanation from Petros.
I would add that my line goes from the pump to the regulator cum gauge on the strut mount and then from that to the PS inlet on the Weber. This is just like splatterdog's setup for fuel routing - seems logical to keep it away from the mani heat.
Funny - I don't remember "probs" like this with the SUs on my many Morris Minors (or Singer with the Solex) so many years ago. Wonder if it was the BritCarbs or the fact that we had "real" gas in those days?
Tom M.
T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"
"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain
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Petros
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Re: Q for the weber peeps

Post by Petros »

My several old Volvo 122s and 444 also used SU carbs, and I never had this problem either. They also had a heat sheild and plastic insulators as I recall. I loved those SUs, a simple and very efficient design with only a few moving parts. And all the "chevy" and "ford" guys could never figure them out, ha!
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
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dlb
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Re: Q for the weber peeps

Post by dlb »

teranfirbt, is this the gasket you're talking about?

http://www.autozone.com/autozone/parts/ ... 563_0_1871_

this could be really useful for people having hood clearance issues with the weber. how thick is this gasket? my carb heat shield (which sits below the spacer) had a paper gasket like this on it already but i'm wondering if the one in the link is thicker.

and FWIW, i have no problem with hard starts with the weber: i pump the gas once before i crank it on cold starts, twice on really cold mornings, and give it a tiny big of gas during cranking on warm starts. i used to have problems with warm starts with the stock carb.
danzo
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Re: Q for the weber peeps

Post by danzo »

Thanks for the replies guys. I really feel the carb is not working properly. I've had quite a few carb'ed cars over the years in hot climates and have never had the hot crannking problem like I do now. It cranks and cranks to hot start even when the outside temp is mild (60-70 at night now). BTW after hooking up the VSV switch to the carb's ported vac there is no change.

My car does have the factory heat shield and aftermarket phenolic spacer (5mm I believe). Like Tom I do get what I think is fuel seepage on the carb spacer. I would think a half inch spacer would cause hood clearance issues, but thanks for the intel teranfirbt, may just try it. I replaced the original fuel pump about the time I did the carb swap. Right now there is no FP regulator since the pressure reads a constant 3psi, but I do have and will install the Holley reg soon.

I really don't think carb/fuel temp is the problem, which is why I starting thinking in terms of how I did the install and/or fuel pressure venting issues. I had this exact same carb on my old Spitfire and never had this problem. In fact it was easier to start when warm even if it was 105 outside.
It's a scientific fact that in a twin engine aircraft, when one engine fails there is always enough power in the remaining engine to make it all the way to the crash site.
teranfirbt
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Re: Q for the weber peeps

Post by teranfirbt »

@dlb: That is the correct gasket.
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Re: Q for the weber peeps

Post by ARCHINSTL »

As mentioned, I used the OE phenolic spacer for the mani heat and PCV flow.
I also ran into clearance probs, even with the Redline "short" filter. I resolved this first by Dremeling away part of the hood's brace and finally, taking a cue from gmeddy's fix, Dremeling the filter element itself shorter (covered, with pix, in a Repair Guide thread). While these solutions were apparently not needed by some - I did need it. A possibility for the need was because I had installed new motor and trans mounts a few years ago, thus raising the motor a tad. Maybe it was also just a manufacturing peculiarity with my car?
Tom M.
T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"
"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain
danzo
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Re: Q for the weber peeps

Post by danzo »

Just thought I'd post an update of sorts. Despite the colder outside temps (40* at night) my fuel boiling persists after shutdown despite the carb body never rising over 150*. I installed the Holley regulator but this didn't make any difference. So I called Pierce Manifolds (whom I bought the Weber from), and as usual they were very willing to talk and offer suggestions. Recommended I check/adjust the float level - it was not moving enough either up or down. I corrected this but it didn't make any difference.

When I installed the regulator I also put a glass 'washable' fuel filter between the pump and reg. After the engine has been shut off the fuel makes bubbles in this filter. I can also see gas percolating near the air jets, or whatever is in the small cavity in front of the main barrels as you look down into the carb. I thought maybe I had a blown/missing gasket but didn't notice anything wrong when adjusting the float.

Next I'm going to buy 10 feet of fuel line and make a custom vent from the pump to the tank. Like I said before the stock vent line was very difficult to blow through (by mouth, not compressor). This problem is driving me nuts since it's killing my mpg - I can see wasted gas dripping in the main barrell after shutoff. Just imagine the hell takza would endure if he were in my shoes!

Any other suggestions?
It's a scientific fact that in a twin engine aircraft, when one engine fails there is always enough power in the remaining engine to make it all the way to the crash site.
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Re: Q for the weber peeps

Post by ARCHINSTL »

I think you are the only one who's installed another filter, whether between the pump and reg or between the reg and carb. Could that be the source of the prob?
I did have a bit of gas leakage, albeit subtle (just stains), from between the carb and the mani, although I dunno whether at the adapter or the phenolic plate.
I tightened the mounting bolts a bit (first time), cleaned the areas, and the leaks/stains did not return.
Tom M.
T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"
"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain
danzo
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Re: Q for the weber peeps

Post by danzo »

Sorry for the delay, I was on holiday the past few days, but I think I solved my fuel boiling problem. I removed my self-installed coat hanger that held down the counterweight on the exhaust manny. It was attached to the valve controlled by a bimetallic spring that directs/diverts hot exhaust air to/from the intake manifold. After about 50 stop 'n' go miles Thursday night the carb temp never got above 115* after shutdown (versus 150* previously). No more bubbling gas in the carb, no more pinging nor hesitation upon startup and it feels like it has 10% more power. The only thing I can figure is that the valve was still directing hot air to the intake even though I thought I had it do otherwise. D'oh.

Maybe the spring is to blame, probably I'm to blame, but I'm just glad it's running better. I want to do away with this exhaust manifold to remove the valve from the equation altogether.

So the $64 question: is there a stock Toyota ex manny that fits into the stock T4 ex system that doesn't contain this valve? Maybe from a fwd Corolla/Nova? Aftermarket? If none exists I plan to get a j-yard manifold and positively disable the valve and spray the whole assy with one of those coatings that supresses heat. The racer guys find them effective at reducing underhood temps.
It's a scientific fact that in a twin engine aircraft, when one engine fails there is always enough power in the remaining engine to make it all the way to the crash site.
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Re: Q for the weber peeps

Post by Lil Beast »

why dont you guy's use the stock air filter housing and cut the hole to mate.Than like that you can retain most emissions. Maybe is the reason of your problems. I run one with no problem at all and dont have to destroy my hood. No cold or hot issues. When cold and i live in the rockys at 3300 feet so when i mean cold it's cold and breezy,pull on the choke give one shot on gas and it goes, when warm just turn the crank 1/4 turn starts if does'nt do the 1/4 turn start, i just pull the choke to the fast idle position and again 1/4 turn start.They only thing i realize so far with mine anyway if i got a hard time to have my engine really warm even if i let idle for 20 min is this a problem???even in the hot okanagan summers 100+ f degrees. Could it be the higher air flow as more cold air draft's in?
Dont let your eyes to fool you!!!

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danzo
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Re: Q for the weber peeps

Post by danzo »

Lil Red thanks for the input but I don't think the lack of the very few emission devices the stock air cleaner houses are the source of my problems. In fact aftermarket carbs like the weber are designed to be stand-alone units that take the place of these devices. The operator just needs to know how to tune them which is why they are so adjustable. I don't have hood clearance issues either. I ran this exact same carb/air cleaner in the same climate on my Triumph (1.5 liter with non crossflow head) years ago with no driveability issues.
It's a scientific fact that in a twin engine aircraft, when one engine fails there is always enough power in the remaining engine to make it all the way to the crash site.
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