). The problem occurs only (sometimes) when hot engin has cooled down a bit for appr. 3/4 hour.
Hot engine stalls when restart - help needed
Thread Starter
Racer
Joined: Aug 2000
Posts: 349
Likes: 1
From: Hofheim Germany
Hot engine stalls when restart - help needed
Hi folks,
since restoring my Tripower-Carb-Setup on my '69 L68, the engine stalls after restart when hot. After turning the key, engine will start after 3-4 seconds, but then stalls.
I have to try it 2 or 3 times and have to pump with the gas-pedal to give higher revs after start. After a few seconds, idling is fine again.
Any idea, what is the reason for that? I haven't this before ...
Regards from Germany
Gerrit
since restoring my Tripower-Carb-Setup on my '69 L68, the engine stalls after restart when hot. After turning the key, engine will start after 3-4 seconds, but then stalls.
I have to try it 2 or 3 times and have to pump with the gas-pedal to give higher revs after start. After a few seconds, idling is fine again.
Any idea, what is the reason for that? I haven't this before ...
Regards from Germany
Gerrit
Drifting
Joined: Aug 2013
Posts: 1,263
Likes: 512
From: perth Aus w.a
2020 Corvette of the Year Finalist (stock)
C3 of Year Winner (stock) 2019
I would disconnect the carb linkage to the end carbs and work on the centre carb ,I used cable ties to make sure the end carbs are not open at all .Set your centre float level ,check your accelerator pump ,turn your idle air fuel screws all the way in the back them out 1.5 turns .get a vacuum gauge and hook it up to full manifold vacuum and start the car if idles to low turn idle speed screw in to get it idling at 850 rpm .Then adjust idle screws and idle rpms till you get the best vacuum .My l68 vacuum is bang on 20hg ,hope this helps .
Thread Starter
Racer
Joined: Aug 2000
Posts: 349
Likes: 1
From: Hofheim Germany
Of course I've already checked the usual points 
.
The problem does'nt occurs always: When engine ist cold, it starts perfect. The same, when it is hot and restarted after a few minutes. But sometimes, when the hot engine has cooled down for approx. 1 hour, I have to pump the pedal for accelerating while starting, to avoid engine-stall. It doesn't seem to be a serious problem, but I did not have that before.
Gerrit
.The problem does'nt occurs always: When engine ist cold, it starts perfect. The same, when it is hot and restarted after a few minutes. But sometimes, when the hot engine has cooled down for approx. 1 hour, I have to pump the pedal for accelerating while starting, to avoid engine-stall. It doesn't seem to be a serious problem, but I did not have that before.
Gerrit
Instructor
Joined: Jul 2004
Posts: 232
Likes: 2
From: Langley B.C Canada
Sounds like we both have the same problems. Mine runs great from a cold start then after running for a 1/2 hour, once its hot she starts to stall and wont maintain an idle unless I feather the throttle. I would check your accelerator pump, your fuel pump and your pcv valve. Possible vacuum leak maybe
Thread Starter
Racer
Joined: Aug 2000
Posts: 349
Likes: 1
From: Hofheim Germany
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Instructor
Joined: Jul 2004
Posts: 232
Likes: 2
From: Langley B.C Canada
Im starting to think vapor lock. Once the fuel from the fuel pump started to pump vapors, then the float bowl has no actual liquid gas to raise the float to close the valve, so then your stuck with a semi empty fuel bowl. Its like fuel soak, where the fuel boils away, then you have to crank over and over to re fill the bowl to start. There is many articles and videos on this problem. It happens to mine to. Do you have side exhaust, which can heat up that fuel line from the tank?
Thread Starter
Racer
Joined: Aug 2000
Posts: 349
Likes: 1
From: Hofheim Germany
The car original was equiped with TI, but had been changed to a breakerless ignition.
The car has (original) sidemount exhaust.
Vapor-lock sounds likely to me. That would explain, why stall doesn't occurs after an immediately restart, but after a while: that lets the fuel boil in the line.
The only doubt is, that I hadn't it the years before ...
Gerrit
The car has (original) sidemount exhaust.
Vapor-lock sounds likely to me. That would explain, why stall doesn't occurs after an immediately restart, but after a while: that lets the fuel boil in the line.
The only doubt is, that I hadn't it the years before ...
Gerrit
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
restored the tripower setup? why? did you rebuild the carbs or somebody else? get a new metering block for the center carb. that, power valve and gaskets. the air bleeds and idle circuit get gunked up and are very difficult to get cleaned out. use orig jets. replacements can be way off in size. or better yet i will trade you a nice Holley 4 bbl setup for that cantankerous irritating tripower... Hell, I tried!
Thread Starter
Racer
Joined: Aug 2000
Posts: 349
Likes: 1
From: Hofheim Germany
First: I'll never change the original setup! Tripower rules 
"Restored" maybe isn't the right term: I've cleaned all parts and replaced power-valve and gaskets. All parts (except the gaskets) remained original.
Finaly I guess, that the "vapor-lock" is the reason.
BTW: Has anyone an idea, where I can get a matching metering-block for my center-carb (# 4056-1A). Number on the metering-block must be 5257.
I've tried all the common dealers, incl. Cranes Corvette, Chicago Corvette, etc. and even Holley itself. Seems, that item is no longer available - nowhere
.
Gerrit
"Restored" maybe isn't the right term: I've cleaned all parts and replaced power-valve and gaskets. All parts (except the gaskets) remained original.
Finaly I guess, that the "vapor-lock" is the reason.
BTW: Has anyone an idea, where I can get a matching metering-block for my center-carb (# 4056-1A). Number on the metering-block must be 5257.
I've tried all the common dealers, incl. Cranes Corvette, Chicago Corvette, etc. and even Holley itself. Seems, that item is no longer available - nowhere
.Gerrit
Last edited by Sir Tripower; Jun 28, 2019 at 07:06 AM.
Instructor
Joined: Jul 2004
Posts: 232
Likes: 2
From: Langley B.C Canada
All I can say is i am having this exact same issue as we speak. I only drove my car three times last summer as a result, and had to garage it to figure out this problem. Mine never really acted up until about five summers ago. It is possible this is the problem with today's fuels and the isobutain they put in the fuels. The fuels from what I am reading online say they boil at a much lower rate. here is an interesting video you should watch.
Last edited by darrentpi; Jun 28, 2019 at 09:49 AM.
Race Director
Joined: Mar 2016
Posts: 14,399
Likes: 8,204
From: Napa Valley California
Send a P.M. to LARS on this forum.
He is the GURU for OEM carbs and he just did a thread on a tri-power set up where he rebuilt and set up the tri-power for another forum member.
He is the GURU for OEM carbs and he just did a thread on a tri-power set up where he rebuilt and set up the tri-power for another forum member.
Burning Brakes
Joined: Jul 2016
Posts: 767
Likes: 74
From: Blaine MN
So far I'm not having this issue ( 4 years of owning the tri-power car, 2 years CI heads, 2 years Alum heads), I've rebuilt the Carbs including helicoil machining corroded bowl screw threads (years of octane booster from p/o's) and had/have some nasty metering block/plate corrosion (bad enough to cause fuel leaks).
(Gerrit, I will check my parts box for the Metering Block, I can also check with the shop that supplied your Bowl Fittings if you'd like).
Do you have the Heat Riser passages blocked off (mine have always been blocked off).
When it dies you could pull sight plugs to verify fuel level (you could check at key off point as well).
(Gerrit, I will check my parts box for the Metering Block, I can also check with the shop that supplied your Bowl Fittings if you'd like).
Do you have the Heat Riser passages blocked off (mine have always been blocked off).
When it dies you could pull sight plugs to verify fuel level (you could check at key off point as well).
Thread Starter
Racer
Joined: Aug 2000
Posts: 349
Likes: 1
From: Hofheim Germany
Many thanks for your helpfull comments once more 
.
I would appreciate any help to get this metering block. Also I can't get a new fuel bowl for the secondaries. Chicago Corvette has it in their catalogue, but told me, that it is out of stock
So if anyone has an idea (or better an adress), let me know.
Regards from Germany
Gerrit
.I would appreciate any help to get this metering block. Also I can't get a new fuel bowl for the secondaries. Chicago Corvette has it in their catalogue, but told me, that it is out of stock
So if anyone has an idea (or better an adress), let me know.
Regards from Germany
Gerrit
Melting Slicks
Joined: Mar 2006
Posts: 2,248
Likes: 67
From: Warrington PA
Finalist 2020 C4 of the Year - Unmodified
Hello Gerrit, don't know if you have tried the company listed below. They have quite an inventory and even though it may not be listed, they may have it. I found a number of items there when I rebuilt my tripower. Give them a try..... Tom
ALLSTATE CARBURETOR & FUEL INJECTION
143 Brightside Avenue
Central Islip, NY 11722
Phone: 631 234-8327
Email: carbdoc@allcarbs.com
Hours of Operation: Mon-Fri 8:30am-4:30pm est Closed Sat. and Sun.
https://allcarbs.com/products-services/
ALLSTATE CARBURETOR & FUEL INJECTION
143 Brightside Avenue
Central Islip, NY 11722
Phone: 631 234-8327
Email: carbdoc@allcarbs.com
Hours of Operation: Mon-Fri 8:30am-4:30pm est Closed Sat. and Sun.
https://allcarbs.com/products-services/
Race Director
Joined: Mar 2016
Posts: 14,399
Likes: 8,204
From: Napa Valley California
Try a search for him in “Threads” Search, Lars in C3 Tech/Performance.
He just started a new thread last week regarding finding Q Jets on Craigslist or eBay..
V8FASTCARS@msn.com
I believe this is his correct email.
He just started a new thread last week regarding finding Q Jets on Craigslist or eBay..
V8FASTCARS@msn.com
I believe this is his correct email.
Last edited by OldCarBum; Jul 4, 2019 at 10:07 AM.
Thread Starter
Racer
Joined: Aug 2000
Posts: 349
Likes: 1
From: Hofheim Germany
Seems, that I've found him. I started search for member "LARS" in capital letters, as written in the thread but couldn't find anyonewith this name. Seems, that in fact, he is written "lars" .
Now I've send him an email and hope, he will answer ....
Gerrit
.Now I've send him an email and hope, he will answer ....
Gerrit