hard starting, stumble on acceleration

klashniv Slammed & Awesome Dubber

82 posts · joined Mar 2006 · 1 Nov 2006, 4:12 pm

#551182

My 12v 1300cc (recently overhauled) 1966 vw beetle has the following condition that am trying to solve. it takes very many cranks to get it to start, usually about 4 lengthy attempts.

When it does start, there is alot of buckling and stumbling and only smoothens somewhat when you rev it high for a while.

Once on the move, hard acceleration will cause a stumble.

Valves have been adjusted, new spark plugs, static timing at 7.5 deg BTDC, single vacuum distributor, 30PICT2 carburetor.

I have narrowed down to either vacuum leak or bad coil, anything else I should look out for?

Thanks

[ Edited on 1-11-2006 by klashniv ]

type3lover in the garage...

796 posts · joined Feb 2005 · 1 Nov 2006, 4:20 pm

#551188

Blocked jet in the idle / low speed fuel circuit?

.

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 · 1 Nov 2006, 4:22 pm

#551190

Just make sure the coil is wired up correctly, as a coil will work when wired up back to front...
but not very good....

either spark... or fuel - carby...

is the auto choke working?
or adjusted correctly...
look down the carby throat and make sure the needle and seat aren't stuck and letting too much fuel down the throat.... which floods the engine....
or
not enough fuel....
carby may need cleaning...
accelerator pump working??
or
is the electromagnetic idle jet connected??
or
How old is the fuel in the car???
as petrol doesn't last too long.... it goes off...

I presume You don't have a Strobe type timing light?

Lee

http://community.webshots.com/user/vw68autobug

- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---

klashniv Slammed & Awesome Dubber

82 posts · joined Mar 2006 · 1 Nov 2006, 4:33 pm

#551192

no strobe timing light 🙁, fuel is pretty fresh (abt 3 days old, emptied tank and refilled), coil is wired up correctly (condensor to -ve, hot line to +ve).

accelertor pump seems to work fine, doubt this would affect startup though, but might cause the acceleration stumble.

carby is missing the idle cutoff solenoid, seems to have screw with a hole in its centre, like an idle jet? (edit: think its called bypass screw, not orignal to carb though)

anyway, will take the carb apart tonight

[ Edited on 1-11-2006 by klashniv ]

xornge666x Wolfsburg Wizard

460 posts · joined Sep 2006 · 2 Nov 2006, 12:56 am

#551379

Sounds like a carby issue, was it fine before the engine rebuild??
If you wire the coil backwards it will fry the points wiring, doesnt sound like that
Is it running fine once warm? It sounds like fouled plugs, possible if excess build oil or someting has fouled them on first few start ups...
Some carbs are simply over in my opinion!! They will never work again, usually due to internal galleries being blocked and or porous. Not likely if it was fine before though...
andrew

klashniv Slammed & Awesome Dubber

82 posts · joined Mar 2006 · 2 Nov 2006, 3:19 pm

#551510

It has been seated for several years before engine was taken apart.

Took the carb apart last night and cleaned it out as much as I could.

Will reinstall it tonight and send feedback on how it is running

klashniv Slammed & Awesome Dubber

82 posts · joined Mar 2006 · 3 Nov 2006, 4:01 pm

#551956

UPDATE:

Took apart the carburetor and cleaned as throughly as I could, blowing air through passages and jets.

Put the carb back on car, runs well but dies at idle, will do carb adjustment and post results from that too.

klashniv Slammed & Awesome Dubber

82 posts · joined Mar 2006 · 13 Nov 2006, 5:55 pm

#554967

this is driving me crazy, the car seems fine til you start driving, then stutters and bucks, accelerates poorly and eventually dies when anywhere near idle.

going to try and change the coil to see whether it helps.

btw, I sucked on the vacuum hose then stuck my tongue in. it slowly returns, cld this be the problem? I assume though that with constant vacuum, it should be able to hold?

xornge666x Wolfsburg Wizard

460 posts · joined Sep 2006 · 14 Nov 2006, 12:54 am

#555135

your vac advance will not make the car stall. If the dizzy is slow to return from advance, it may take a little longer to return to normal idle, or if the diaphram is leaking (and adv not working) the carb may suck air and idle up and down, but this doenst sound like its happening....
Coils will generally break down at revs, and most likely under load, but wont cause the car to stall.
I would look at getting another carb. I have spent hours in the past trying to get a carb to run right, had them apart blown them out, torn my hair out!! Sometimes it is a lot easier to get one from a wreckers, or you may find one here that someone can say was running recently and well... It is getting hard to find really good ones though, as they are getting old. In my opinion, if you are keping the car, the best thing to do is get a brand new one. Bolt it on, tune it up and away you go. Costs a little more I know, but saves a whole lot of frustration and stress!!

klashniv Slammed & Awesome Dubber

82 posts · joined Mar 2006 · 14 Nov 2006, 3:12 pm

#555277

i hear you, i hear you

klashniv Slammed & Awesome Dubber

82 posts · joined Mar 2006 · 14 Nov 2006, 10:08 pm

#555425

problem found!

it turns out, there was a current leakage where the spark cables enter the distributor cap (found it only after a nasty shock while checking whether they are fitted well with car was running).

after applying alot of tape, everything sounds ok now, guess its time to replace the cables.

xornge666x Wolfsburg Wizard

460 posts · joined Sep 2006 · 15 Nov 2006, 5:01 am

#555452

strange... an engine will idle on 2 cylinders usually. Rough, but it will definately run. Hope its all sorted anyway!! Check for corrosion in the cap terminals where the leads push in if its been sitting for some time. Often builds up in there.