popping and stumble

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audiocontr
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popping and stumble

Post by audiocontr » Sat Jul 09, 2016 11:56 am

Keep in mind that this is my first Haffy, so these may be normal:

Ive noticed that the haffie will pop at idle until quite warm. I have to really pull on the choke to relieve the issue, and ive also noticed that it will stumble at slight throttle while shifting. Its always slight throttle. Eventually is gets better once warm. The throttle is not as responsive as i would assume its supposed to be, if that makes any difference

I've also noticed a wave of power up and down while cruising at 60 km/h.

The previous owner installed a mr gasket 12 v fuel pump for carbs when he realized the stock pump wasnt working. Could this all be related to a poor after market fuel pump?
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
1979 Mini Ranger For Sale
1986 Corvette For Sale
2001 F250 Diesel and trailer
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TechMOGogy
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Re: popping and stumble

Post by TechMOGogy » Sat Jul 09, 2016 3:18 pm

It could be
Do you know the pressure it is running at?
I have a cheapy 12v pump too and Hafi does not (did not, as it is in pieces) act like that.
Could be the carb
72 Pathfinder | 75 710M 2.7i | 96 350GDT Worker

Heinkeljb
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Re: popping and stumble

Post by Heinkeljb » Sat Jul 09, 2016 3:23 pm

Sounds like you have fuel problems as well as all the other issue you normally face when getting a "new" to you vehicle!

Have you made sure that you have at least one fuel filter before the pump and possibly one after if your tank is really full of crud.

Next take the top off your Carb and check the float chamber is clean. Whilst you are there check the fuel level. Then take off the cover which hide the idle jets. Take all 4 jets out and preferably using compressed air rather than a piece of wire or anything similar, make sure they are all clear.

These engine seems to be quite sensitive to rubbish in the fuel system.

John

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audiocontr
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Re: popping and stumble

Post by audiocontr » Sat Jul 09, 2016 4:00 pm

Yup yup, lots of fun found in this truck :roll:

Thanks for the suggestions. Fuel filters are clean. They're very new.

I'll pop the top of the carb. Where can I find the proper settings for the float level?
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
1979 Mini Ranger For Sale
1986 Corvette For Sale
2001 F250 Diesel and trailer
Company Cars
2019 Expedition
2019 F-150

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Garrycol
Australia
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Re: popping and stumble

Post by Garrycol » Sat Jul 09, 2016 8:03 pm

Not normal - the fact it has an electric fuel pump is not an issue in itself but if it has too high pressure it could cause issues. What varb do you have? If it is the NDIX 32 check the floats - they are plastic and glued together and the glue can break down so the floats dont work so wel - floods at lower revs.

Make sure the accelerator pump is adjusted correctly as it could cause the hesitation you mentioned.

Garry
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

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audiocontr
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Re: popping and stumble

Post by audiocontr » Sat Jul 09, 2016 8:20 pm

Its not a Pinz carb, i know that for sure.
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
1979 Mini Ranger For Sale
1986 Corvette For Sale
2001 F250 Diesel and trailer
Company Cars
2019 Expedition
2019 F-150

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Garrycol
Australia
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Re: popping and stumble

Post by Garrycol » Sat Jul 09, 2016 11:17 pm

So the older Weber - cant help with that. :(
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

one2many
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Re: popping and stumble

Post by one2many » Mon Jul 11, 2016 4:52 am

Weber's like around 3 psi and will overwhelm the float anything above 4.5 psi. I would say the popping is likely excess fuel popping in the exhaust from a slightly high fuel pressure, a lot of those cheap 12volt pumps will easily run 6 to 7 psi even if the are rated to 4. Either fix the original mechanical pump or use a good quality 12 volt pump like Holley or Goss and buy one rated to no higher than 4.5 psi, even then I would still put an adjustable fuel regulator inline with an electric fuel pump because its just good practice. I recently bought a 1.5 to 4.5 psi 12 volt Holley pump on eBay for $80 Australian dollars (aud) and an Aeroflow adjustable fuel regulator for $60 aud but for a different vehicle. I would think you could put a kit through the original mechanical pump for less than that.

The other thing that causes popping at idle through the exhaust is burnt/leaky exhaust valves but from what you've said about the el-cheapo pump installed I would be suspect on that being the cause.

Good luck.
1985 pinzgauer 712K factory 2.7lt civilian (RHD, 4 door K)
1979 Volvo tgb 1314a (under construction to om606 diesel/722.6 trans. Dual cab/tray)

Czechsix
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Re: popping and stumble

Post by Czechsix » Sat Apr 01, 2017 10:23 pm

I just went and got a couple of original swiss electric fuel pumps, but the other thing that you'll find when it's popping is that there are exhaust leaks right at the cylinder head elbow. Deceleration it starts getting worse.

As has been said, check your fuel supply, also check points and condenser. Electrical usually gives more trouble once it's warmed up.
1963 Swiss 700AP, with Black Diamond ATV tires, and a few other mods. "Always under construction".

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audiocontr
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Re: popping and stumble

Post by audiocontr » Sat Jul 01, 2017 12:29 pm

Raised the float level and tremendous improvement. Almost perfect.

Anyone know the weber float level spec or procedure?
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
1979 Mini Ranger For Sale
1986 Corvette For Sale
2001 F250 Diesel and trailer
Company Cars
2019 Expedition
2019 F-150

Czechsix
United States of America
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Joined: Sun Oct 12, 2014 10:38 pm

Re: popping and stumble

Post by Czechsix » Sat Jul 01, 2017 1:19 pm

audiocontr wrote:Raised the float level and tremendous improvement. Almost perfect.

Anyone know the weber float level spec or procedure?
For the one barrel ICS?

The way I've done it is take top cover off, make sure needle valve is working. Check tab on float to make sure it's smooth. Check floats to make sure they're equally aligned.

Hold the cover vertically, so the float is hanging down. Float tab just touches the needle valve.

Measure the distance between the surface of the cover and the float drum - you're looking for 2mm. If not, take a pair of smooth faced needle nose pliers, or jeweler's pliers, and bend the tab until you get that measurement. I'll usually gently flop the float back and forth and try several times to get that 2mm.

That's all I do, put it back together making sure nothing is hitting the float, and you're done.
1963 Swiss 700AP, with Black Diamond ATV tires, and a few other mods. "Always under construction".

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audiocontr
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Re: popping and stumble

Post by audiocontr » Sat Jul 01, 2017 4:30 pm

Interesting! Thank you!!
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
1979 Mini Ranger For Sale
1986 Corvette For Sale
2001 F250 Diesel and trailer
Company Cars
2019 Expedition
2019 F-150

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