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Engine runs strong but no boost.
Posted by: DOUG WARD ()
Date: September 16, 2019 09:23PM

My 65 Corsa 180 has a strong engine, but I can't get any boost . I found & fixed a couple of exhaust pipe leaks, had the carb rebuilt, set the timing several times, made sure the thermister is working, & tested the gauge by blowing 20 pi into the hose at the head hook up. While the carb was off, I checked to see that the turbo impellor is free & it turns with a light finger push. BTW, my fuel mileage is between 9.5 & 12 mpg. ( I think that sucks )
Anybody have any ideas ? Doug Ward

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Re: Engine runs strong but no boost.
Posted by: 63turbo ()
Date: September 16, 2019 09:47PM

I think your lack of boost is strongly related to the poor fuel mileage... you should be getting something like 16-18 anyways. Pig rich kills boost! Something isn't right with your carb, and the simplest 2 things I can thing of is the float setting is way wrong and or the accelerator pump circuit is screwed up- this will cause large amounts of gas to be going into the engine at all times.

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine runs strong but no boost.
Posted by: MattNall ()
Date: September 16, 2019 10:19PM

Put a pair of SMALL Vice Grips on the rubber hose leading to the carb.... keep tightening 1/2 turn at a time until you see a change for the good...or it runs out of fuel when accelerating!. Easy Test!

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Engine runs strong but no boost.
Posted by: JimBrandberg ()
Date: September 17, 2019 04:52AM

There's a lot of Corvair turbos out there not making any boost. A lot of folks wish for a quick fix like rebuilding the turbo but often the turbo is fine and there's some other bugaboo. I hope you keep us posted on how it's going.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Engine runs strong but no boost.
Posted by: jjohnsonjo ()
Date: September 17, 2019 05:10AM

Did you ever get boost with the car??? Don't expect any when not in gear or 1st gear. The real test is with a fully heated engine in 3rd or forth gear at highway and higher speeds with the engine above 3500 RPM.

Now back to the carb, you said it was rebuilt. Did you check the square block that holds the accelerator pump down for flatness. If not it will leak. Also, make certain the choke is turning off fully.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa


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Re: Engine runs strong but no boost.
Posted by: alan_smithee ()
Date: September 17, 2019 07:33AM

I had the same problem when I got mine. Turned out to be a stuck/carbon'd turd!bo. A really hot day and driving that thing consistently solved my problem without having to tear anything apart. Hopefully you are in the same boat. Keep us posted

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Re: Engine runs strong but no boost.
Posted by: Timothy Shortle ()
Date: September 17, 2019 08:38AM

Seems I have heard if you "don't use it, you lose it". They need to be taken out occasionally and DRIVEN HARD. Going up a long hill in 3rd is a good way to test.
In theory I am saying the same thing alan is saying, just using a lot more words.

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Re: Engine runs strong but no boost.
Posted by: Frank DuVal ()
Date: September 17, 2019 11:09AM

Quote
Matt
Put a pair of SMALL Vice Grips on the rubber hose leading to the carb..

You mean the one in the driver's side wheel well area? There is no rubber hose in the engine compartment on a stock system, except for the 3/16" return line.

Now, the vicegrip on the rubber return line hose is a great get me home tip when the rubber tee at the fuel tank splits open.thumbs up

I agree with the above, put it in third and floor it and watch the gauge. And the cars with the radar guns....grinning smiley

Have you confirmed the throttle plate in the YH actually fully opens when you put your foot to the floor? I see this error all the time. Not full open = no boost.

Frank DuVal

Fredericksburg, VA

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Re: Engine runs strong but no boost.
Posted by: AlecCarlson ()
Date: September 17, 2019 11:18AM

I had a similar problem on. My ‘65 turbo. Tried a lot of diagnostic tests. Turned out the vacuum / boost gauge only read vacuum. The boost side didn’t work. You might try a different gauge and check it against the stock gauge.

Alec

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Re: Engine runs strong but no boost.
Posted by: DOUG WARD ()
Date: September 17, 2019 05:44PM

Thanks guys , for the replies .I DID get some boost a few months ago ( not much, maybe 3 to 5 psi.) I took some advice from a pretty knowledgable guy & tried a larger main jet in the carb. I haven't seen ANY boost since then. From what you guys have suggested, I think I'll undo that larger jet & go smaller than before & see what happens. ( the spark plugs are also pretty black now, which indicates a too rich mixture too ). I'll keep you posted with the results. Doug Ward

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Re: Engine runs strong but no boost.
Posted by: JimBrandberg ()
Date: September 18, 2019 05:11AM

Yes too rich can be a problem. Lean and mean to a certain extent. 10 MPG is a clue.
As an aside, what are you using for spark plugs?

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Engine runs strong but no boost.
Posted by: alan_smithee ()
Date: September 19, 2019 03:46PM

Any update on the boost issue?


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Re: Engine runs strong but no boost.
Posted by: DOUG WARD ()
Date: September 20, 2019 09:27PM

OK guys, here's my update. I removed the larger main jet & replaced the original one. I also found that the accelerator pump needle valve was missing. The carb had / has been dripping fuel out of the throat . It continues still, even after I put in the missing needle valve.( brass ) Oh, BTW, I also lowered the float level by about 3/16th. Still getting about 9 MPG. Still dripping fuel out of the carb. This is a pretty simple carburator but it has given me fits . The carb is obviously flooding and running too rich. Not much of an update, but I'm trying.
the spark plugs were Champion RL12Y. They were black & sooty. I changed them to AC Delco R44F. ( the book specs R44FF but I could'nt find any FF's ) They are still black & sooty.
Thanks for trying to help me sort this out guys. I'm still open to more ideas. Doug Ward

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Re: Engine runs strong but no boost.
Posted by: MattNall ()
Date: September 20, 2019 10:02PM

Did you pinch off the hose as I instructed? Or put in a pressure regulator or a fuel pressure gauge!

Pinching the hose is fast and simple!

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Engine runs strong but no boost.
Posted by: alan_smithee ()
Date: September 20, 2019 11:40PM

not to disparage the fuel pressure regulator idea...but I am running a generic electric fuel pump with no regulator. Initially I thought that a regulator would help my lack of boost problem. It didnt. Consistent driving brought the turbo back to life.


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Re: Engine runs strong but no boost.
Posted by: jjohnsonjo ()
Date: September 21, 2019 05:31AM

A lot of us are running Grose fuel ball valves, I believe Clarks still sells them.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa


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Re: Engine runs strong but no boost.
Posted by: 63turbo ()
Date: September 21, 2019 06:17AM

DOUG WARD Wrote:
-------------------------------------------------------
> Thanks guys , for the replies .I DID get some boost a few months ago ( not much, maybe 3 to 5 psi.) I took some advice from a pretty knowledgable guy & tried a larger main jet in the carb. I haven't seen ANY boost since then. From what you guys have suggested, I think I'll undo that larger jet & go smaller than before & see what happens. ( the spark plugs are also pretty black now, which indicates a too rich mixture too ). I'll keep you posted with the results. Doug Ward

Here's a neat video on the Carter YH accelerator pump circuit:[www.bing.com]

After I watched this, I was reminded of a particular thing that can go wrong with the YH, and the symptoms of it are dribbling gobs of fuel. As this video shows, there's 2 check balls that have to be functioning properly, and if they are stuck in one position, it can cause fuel to get sucked out... effectively causing the accelerator pump to be "on" at all times, and could possibly be the source of your excessive fuel consumption

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine runs strong but no boost.
Posted by: DOUG WARD ()
Date: September 21, 2019 11:21PM

Kevin, I watched the video & wasn't aware of the 2 check valve / balls. I'll check that out tomorrow & see what happens. ( Great video ) Doug Ward

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Re: Engine runs strong but no boost.
Posted by: DOUG WARD ()
Date: September 21, 2019 11:24PM

Matt, I still am confused as to where is the rubber fuel hose that you suggest pinching down ? Doug Ward

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Re: Engine runs strong but no boost.
Posted by: MattNall ()
Date: September 22, 2019 08:11AM

Left rear wheel well

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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