Carburetion

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dlee11777
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Joined: Sun Jan 11, 2015 5:58 pm

Carburetion

Post by dlee11777 »

I have a Manx on a 1967 chassis. I have a 1641, but is stock otherwise. I've had a stock carb on it for years and it never failed me. A couple of years ago, I had a fellow install dual Dellorto's on it. It started and ran fine to get home. It sat for a month or so and has never started since I brought it home. I want to drive my buggy. I'm thinking about putting the old 30 Solex back on but wanted to get some feedback from some of you.

In my boxes of spare parts, I have 2 Weber 32 36 DFAV carbs which I was told by the fellow who put the Dellorto's on, that these carbs were too old and he would not recommend using them. I also have 2 EMPI 2 barrell manifolds. Should I stick with the old 30 Solex or try a newer Solex or Weber? I am not what you would call a mechanic anymore, so I want something trouble free. Any advise anyone can give me would be appreciated. Thanks.

Dan
lastmanx
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Re: Carburetion

Post by lastmanx »

get real if it sat for 2 months with todays gas in it; the gas is your problem. simply put todays modern gas goes bad very bad within 2 months. it has congealed in your carbs and pump most likely. first get the old gas out of tank and lines then clean carbs it is what needs to be done. you can change the carbs if you want but the old gas has to go. this is true for modern cars also,lawnmowers etc. if you have a car or gas powered anything that is not used routinely use a gas stabilizer product in the tank. if you store a vehicle for long periods (like winter) drain the gas and run car dry. I have done this for 16 years (winter storage) and had no issues. the old trick of starting a stored vehicle every month no longer applies . it happens here with summer storage of snowmobiles. worst case would be a rebuild on the carb. good luck.
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jsturtlebuggy
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Re: Carburetion

Post by jsturtlebuggy »

What kind of dual Dellorto's do you have? Are they single barrel or dual barrel carbs?
Yes the gasoline we now have with the Ethanol in it does go bad in a short period of time, but I had no problems with setting for several months other then the octane rating goes down. After about 6 months is really goes bad without something like Stabol in it.
Dual carb problems can sometimes be a problem with the air cleaner setup being not up to par and allowing debris to get inside of carbs. Also the use of cheap fuel filters is not good either.
If you are relying on others to do maintenance on your buggy, It may be wise to go back to the single carb if it something that you know how to work on. It will cost you power in going back to the single carb, but make less headaches for you in the future.

And welcome to the Manx Club.
Joseph
Manx Club #1095
Having fun with Buggies since 1970
Worked in VWs in shops since 1970
dlee11777
Posts: 3
Joined: Sun Jan 11, 2015 5:58 pm

Re: Carburetion

Post by dlee11777 »

Last Manx and JSTurtlebuggy. Thanks you for your feedback. I hadn't realized that the newer fuel would go bad so quickly. I know it the past, I could let my buggy stand over the winter and go out and start that baby right up without a hitch.

As for which carbs I have, they appear to be large single barrel Dellorto's. I say appears, because I cannot get the air cleaners of due to tight clearance. My friend apparently had the engine out to install the new carb settup and installed the air cleaners before re-installing the engine. I do believe your are right though, I should just go back to my stock single barrel Solex so I don't have these kind of situation. Is there a better single Solex carb than the old 1967 model 30 that I have? As for power, I didn't notice a strong power difference with the Dellorto's than I had with the old pict 30.

If either of you have any further information that would help, please let me know. Thanks again to both of you.
lastmanx
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Re: Carburetion

Post by lastmanx »

a 30/31pict brand new are generally good to go right out of the box. do not use the 34pict on a dune buggy it has no bushing for the throttle on carb and is sensitive to dust dirt that will prematurely wear it out. it starts out first with vacuum leaks that drive you crazy thinking timing is off until eventually you get a gas leak. if used off road it happens quickly. the hp book on prepping dunebuggies covers this. even with street use a buggy engine is out in open compared to a enclosed beetle engine under its lid. been there done that.
dlee11777
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Re: Carburetion

Post by dlee11777 »

Last Manx, thank you so much for your insight. I will get me a pict 31. Don't know the difference between the 30 and 31, so I will research this. Thanks again.
Momboy007
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Joined: Fri Apr 01, 2016 6:56 pm

Re: Carburetion

Post by Momboy007 »

Hello All,

My 1600 DP currently has a 34Pic 3 installed and seems to occasional backfire and act kindof weird, should I be going to an 30 or 31 pict??? what does pict 3 mean?

Thanks for all your help

Rick
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jsturtlebuggy
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Re: Carburetion

Post by jsturtlebuggy »

A PICT-3 would be the third variation of the 34 PICT carburetor. There was a PICT-4 that used a thermostatic controlled accelerator pump.
The 34 PICT-3 does not work well with an 009 distributor or really any mechanical distributor that has to set the timing at idle at more than 5 degrees advance. It causes a hesitation that is hard to get rid of.
If you are having backfiring problems, it may be to lean. Other reasons include no heat on intake manifold can cause icing on it, also dirt getting into jets can cause problems. There are other reasons too. Without seeing or hearing how it running it is very hard to give real answers to the problems. It may be wise to have someone with experience work on the buggy for you.
Joseph
Manx Club #1095
Having fun with Buggies since 1970
Worked in VWs in shops since 1970
Momboy007
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Joined: Fri Apr 01, 2016 6:56 pm

Re: Carburetion

Post by Momboy007 »

Hello,
Mine is actually running a bit rich as I keep it at 7200 Feet above sea level, It does have a 009 distributor, not an actual 009, but an equivlant with mechanical advance. It does have a pretty big hesitation and the carb was just rebuilt

What is your recommendation?
Thanks in advance
Rick
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jsturtlebuggy
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Re: Carburetion

Post by jsturtlebuggy »

Get a different distributor that has a vacuum advance along with mechanical advance like came with the carburetor on stock VWs.
Something like the one in the picture, this is a 034. Aircooled.net and other carry them.

http://vwparts.aircooled.net/v/vspfiles ... port-2.jpg
Joseph
Manx Club #1095
Having fun with Buggies since 1970
Worked in VWs in shops since 1970
lastmanx
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Joined: Sun Mar 29, 2015 7:40 pm
Location: Ashland Massachusettes

Re: Carburetion

Post by lastmanx »

try anything you want but it won't fix the problem. as previously stated 34pict is sensitive to dust and dirt. change to an earlier carb. or you can wait until the carb leaks gas at throttle shaft through the carb and then you will understand what i'm talking about. right now you are experiencing the vacuum leak associated with the throttle shaft not having the brass bushings the other carbs have. put a brand new 34pict carb on and it will work great until it also wears out. do a little research this is well proven info. personally I have experienced this issue when I was a newbie. definitely change to a vacuum advance distributor this will prove to you as it will have big issues as it operates on vacuum that is messed up with your worn 34pict carb. I had a vacuum advance distributor when I had a 34pict and it helped diagnose the problem. have fun changing parts and keep smiling.
Momboy007
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Joined: Fri Apr 01, 2016 6:56 pm

Re: Carburetion

Post by Momboy007 »

LastManx,

So Am I hearing you say replace the carb with an older one? Which one do you recommend, and lastly, how about the distributor, keep it or change it out?

Rick
lastmanx
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Location: Ashland Massachusettes

Re: Carburetion

Post by lastmanx »

yes change to a 30/31pict carb they have a 12 volt idle circuit and are very durable. keep the distributor. the main difference between a 009 style and vacuum advance distributor is with 009 you are on the gas more. in other words your actions affect/control the performance more. by keeping rpm's up you effect the advance. so you need to pay more attention on how you drive:be more alert to your engine. the vacuum advance type auto corrects your actions. you can hammer the throttle but the advance wont come up till vacuum increases:so get lag or smooth acceleration. no stall. it makes it idiot proof for drivers. sorta like an auto trans will shift for you so you can't miss a shift compared to a standard trans in a normal vehicle. 009 you can rev motor bringing advance up quicker than vacuum; which is why it was used for drag car situations. now truth is both types work great. if you don't need quick performance and don't want to pay attention to your motor vacuum is for you. but you already have the 009 so it wont cost you any $ to learn to drive with it. the back fire you experience is usually caused by exhaust leak. check manifold gaskets if bad replace with best you can find. if the exhaust is fine it is your carb. take a look at it today and be sure it's not leaking gas at throttle shaft;as it could catch fire. inform yourself by reading some books. these are 50 year old cars and any situation you encounter is well documented with advice to correct it. you could find your answers instantly with turn of page. none of this is new.
Momboy007
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Joined: Fri Apr 01, 2016 6:56 pm

Re: Carburetion

Post by Momboy007 »

LastManx,

Will the 30/31 pict work with my current intake maniford? Also, if I decide later to get a vacuum advance distributor, will the 30/31 pict carb support the vacuum needed?
Do I tell my parts guy a want a 30 or 31 Pict, is there a 3 in it also like the 34Pict 3, what exactly am I looking for?

Thanks,
Rick

PS, I bought the book you mentioned to me a while back by John Muir
lastmanx
Posts: 394
Joined: Sun Mar 29, 2015 7:40 pm
Location: Ashland Massachusettes

Re: Carburetion

Post by lastmanx »

yes there is a spacer / adapter piece available some sell it with the carb some separate you will need the adapter. some list it as 30 pict 3 12 volt. brosol brand or empi brand your choice. both are meant for single port . buy adapter that says will adapt to dual port manifold. and of course new gaskets need two one for 34pict adapter one for 30 pict. sometimes come with adapter. parts guy? out here nobody has this stuff so we go online. look yourself find the best deal. the carb will work with vacuum advance dist. but you don't need to change it yet or ever. so if keeping the 009 you will have to block the carbs vacuum outlets, like you did with your 34pict(right?). get the Bently manual for good real pictures, the other to see the potential your buggy can have when your ready. you want the 31pict with square bowl. and keep reading the books you are now asking intelligent questions. keep smiling and buggy on hope this helps.
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