2lt Aircooled stuttering uphill / under load

[j4jon]

Not sure if this should be in electrical or mechanical.

I've got a 2lt Aircooled which has a set of 40 DRLA Dellortos. On a trip recently on the way home it was running fine on the flat, but when going up hill it would splutter and slow right down to maybe 30 in 3rd on the hills on the A34. As the carbs hadn't been tuned I took it to a rolling road got it ballanced, jetted and running fine. Took it back out on the A34 and pulls fine on the flat but still doesn't like the hills.

I've changed the plugs, cap, rotor arm, coil as it felt it was missing but made no difference. Took it back to the rolling road and it has gone lean across the range so I've put in a new electric fuel pump as recommended by eurocarb but still doesn't like the hills.

Can anybody give me any pointers on what to check/ try next?

[paul66beetle]

I'm interested in the answer to this. I have a 2l Aircooled and had a similar problem with it running lean and playing up a bit. MOt station tweaked it a bit and its a bit better but still not perfect!

Going to subscribe to this thread.

[BOXY]

Did the rolling road print-out give you a BHP figure? The CU engine only had 70BHP to start with I think, maybe it's just down on power after 25 years?

[T25rc]

Have you checked your airfilter? Mine was spluttery up hills... A disgusting airfilter was partly to blame. After taking it out its MUCH smoother.

[paul66beetle]

Well mine is a genuine 50,000 miles documented so shouldn't have lost much. My filter is brand new all new electrics just running lean MOT station tweaked it for MOT as C02 was well within tolerance but HC was high pointing to a lean setup. Worse since MOT

[billybigspud]

richen it up a bit, mine was doing it and that is what i did. not as if you will save much fuel on these thirsty beasts. also get the carbs balanced.

jamie

[paul66beetle]

richen it up a bit, mine was doing it and that is what i did. not as if you will save much fuel on these thirsty beasts. also get the carbs balanced.

jamie

Found an air leak, which was causing it to run lean. The rubber braided hoses on the pipes will all be replaced as altering the mixture didn't help.

[billybigspud]

cool, glad you sorted it

jamie

[kevtherev]

Misfire under under load (with full throttle) is a classic air leak symptom
glad it's sorted.

[tamson]

I'm having a similar lack of power problem. I adjusted the timing to 5 degrees ATDC as per haynes manual on Saturday and took it for a 30 mile drive. Absolutely no power and struggled to get up any kind of speed. However I also took the dizzy cap off and cleaned the electrodes and the rotor arm with some wet or dry as they were a bit black and slightly pitted. Is it possible if I might have sanded it a bit too much?

[kevtherev]

Fuel delivery from the tank to the cylinder is often by passed for the lure of a failed electrical component
poor power and performance is fuel and timing related.

[paul66beetle]

Misfire under under load (with full throttle) is a classic air leak symptom
glad it's sorted.

I never had a misfire, just had a really lean figure at the MOT and changing the mixture didn't have much effect if any. Spraying the carbs with cleaner indicated the air leak!

[tamson]

Misfire under under load (with full throttle) is a classic air leak symptom
glad it's sorted.

I never had a misfire, just had a really lean figure at the MOT and changing the mixture didn't have much effect if any. Spraying the carbs with cleaner indicated the air leak!

How does spraying with carb cleaner indicate leak? I sprayed some on my carbs as Im having same problem. Noticeable increase in revs, although hard to pin point exactly where leak is?

[kevtherev]

The carb cleaner acts like a fuel and makes the engine run faster or splutter depending on how much is sucked in.
be carefull on the paint with it and don't let it get sucked in the normal way to fool you

try localising the spray

[tamson]

Ok so is it normal for a slight increase in revs and the spluttering indicates that there's too much of an air leak?