UPDATE 2 Adjusting timing propane engine and impco 425 mixers

Propane, Butane, LPG, GPL, C3H8, C4H10
Caddy123
Posts: 30
Joined: Sat Dec 01, 2018 2:41 pm
Location: Netherlands

Re:(UPDATE) Adjusting timing propane engine and impco 425 mixers

Post by Caddy123 » Sat Jan 12, 2019 1:18 am

Everyone a happy and healthy new year.
I was a little bussy and has a little problems with the car.
I has a vaccuum leak at the intake gasket fix it now and my heather core leak, change it for a new one.
Now i can tune the engine .
To be continued .
Danny

Caddy123
Posts: 30
Joined: Sat Dec 01, 2018 2:41 pm
Location: Netherlands

Re: UPDATE!! Adjusting timing propane engine and impco 425 mixers

Post by Caddy123 » Sat Jan 12, 2019 3:34 pm

I have check the 425 mixers also and the idle cirquit no holes in it.
If i screw the idle mixer allen head (in) the engine stalls if i screw it out to the middle its ok if i screw the screws more out there is no difference rpm go not higher or lower how is that possible!!
Im adjusting only idle now and set the timing.
I have a vaccuum gauge and film it so you can see how its run.
Its run like crap! rough idle fluctuating needle see film.
If i adjust the idle screws and have set the timing im comming not higher than 14-15 hg ok mayby the cam its a lttle bigger 270-270-224-224 lift 511 110 lsa.
But why fluctuate my vaccuum and idle rough.
Gr Danny

storm
Posts: 648
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: UPDATE!! Adjusting timing propane engine and impco 425 mixers

Post by storm » Sat Jan 12, 2019 7:21 pm

Have you sealed the hole in the middle of the Holley baseplate? If you haven't you will have an unmetered vacuum leak.

Take a look at the attachments, see the Holley baseplate has a hole in the centre. If this is not blocked off you will have a vacuum leak. Now look at the QuickFuel billet baseplate and see how it doesn't have the hole in the centre.
Attachments
112-117.jpg
Holley baseplate with hole in centre.
12-750qft.jpg
QuickFuel billet baseplate without hole in centre
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Fuel flow requirements calculations viewtopic.php?f=5&t=1638

Caddy123
Posts: 30
Joined: Sat Dec 01, 2018 2:41 pm
Location: Netherlands

Re: UPDATE!! Adjusting timing propane engine and impco 425 mixers

Post by Caddy123 » Sun Jan 13, 2019 1:47 am

Storm i have this baseplate my gasket blocks all the passages and holes , the middle is still open!!!
If this is the solutuion im very happy .
Intake no leaks
Hoses all new now leaks
Brake booster tested not leak.
Than the hole must be the case!!but where does it take the false air from?
If my gasket blocks all the other passages and holes?
Thanks Danny
Attachments
Screenshot_20190113-074445.jpg

storm
Posts: 648
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: UPDATE!! Adjusting timing propane engine and impco 425 mixers

Post by storm » Sun Jan 13, 2019 2:43 am

Get a small grub screw (can't remember the size sorry), tap the hole part way down use some locktite and screw the grub screw in from the top.
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Fuel flow requirements calculations viewtopic.php?f=5&t=1638

Caddy123
Posts: 30
Joined: Sat Dec 01, 2018 2:41 pm
Location: Netherlands

Re: UPDATE!! Adjusting timing propane engine and impco 425 mixers

Post by Caddy123 » Sun Jan 13, 2019 3:22 am

If this is the solution i send you a pic of a bottle of beer🤣
Break in the engine with my holley gasoline carb no problem and idle ok.
So the problem must be the hole i hope so, im tired after seeking for a month now🤔

Caddy123
Posts: 30
Joined: Sat Dec 01, 2018 2:41 pm
Location: Netherlands

Re: UPDATE 2 Adjusting timing propane engine and impco 425 mixers

Post by Caddy123 » Sat Feb 09, 2019 2:58 pm

...
Last edited by Caddy123 on Sat Feb 09, 2019 3:13 pm, edited 1 time in total.

Caddy123
Posts: 30
Joined: Sat Dec 01, 2018 2:41 pm
Location: Netherlands

Re: UPDATE 2 Adjusting timing propane engine and impco 425 mixers

Post by Caddy123 » Sat Feb 09, 2019 2:59 pm

Hello i have closed the hole in the baseplate.
Not any difference so i looked further.
I have set the idle and timing with a vaccuum gauge and lissening good to the engingine.
But with the timing light i has 25 degrees advanced, that is not good!
And my vaccuum advance doesnt respond if i hook up!
So i set it on 16 degees now 18 advanced has a knock full throttle 16 is ok now. Total with vaccuum connected (response well now) 25 advanced
But i must the idle screw screw in 2.5 times or the engine will not idle.
So my butterflys are to much open now, i have now the same vaccuum on ported and full intake vaccuum .
Setting the mixers now is a way better but the engine shakes under 1000 rpm.
What i doing wrong!!!!

Gr Danny

storm
Posts: 648
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: UPDATE 2 Adjusting timing propane engine and impco 425 mixers

Post by storm » Sat Feb 16, 2019 9:09 pm

Let's clarify terminology before we go any further.
Idle screw = the Idle mixture screw on the side of the mixer.
Idle speed screw = the screw on the base plate the opens the throttle blades.
What ones have you adjusted and how far are they?

Next question have you run the engine with just 1 mixer, alternating between the 2 to see how it idles on 1 mixer?
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Fuel flow requirements calculations viewtopic.php?f=5&t=1638

Caddy123
Posts: 30
Joined: Sat Dec 01, 2018 2:41 pm
Location: Netherlands

Re: UPDATE 2 Adjusting timing propane engine and impco 425 mixers

Post by Caddy123 » Mon Feb 18, 2019 1:38 am

Storm the idle speed screw of the baseplate.
I have run the engine with1 mixer adjust one by one with the idle mixtre screw.
Runs rough even with one mixer!!
Cold engine set the idle speed screw 1 turn more or the engine will not idle, if the engine is warm up the rpm rises i must set the idle speed screw back if the engine is warm 1 turn

Caddy123
Posts: 30
Joined: Sat Dec 01, 2018 2:41 pm
Location: Netherlands

Re: UPDATE 2 Adjusting timing propane engine and impco 425 mixers

Post by Caddy123 » Mon Feb 18, 2019 5:55 am

I will send a sound clip but doesnt work!
Can i send it to your email?

storm
Posts: 648
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: UPDATE 2 Adjusting timing propane engine and impco 425 mixers

Post by storm » Mon Feb 18, 2019 1:29 pm

yep
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Fuel flow requirements calculations viewtopic.php?f=5&t=1638

Caddy123
Posts: 30
Joined: Sat Dec 01, 2018 2:41 pm
Location: Netherlands

Re: UPDATE 2 Adjusting timing propane engine and impco 425 mixers

Post by Caddy123 » Mon Feb 18, 2019 1:50 pm

Cant not find your mail adres!

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