11 replies to this topic

[Disco Dan]

Model: MK4
Year: 1982
Description of problem (please be as in depth as possible):

* Carb cleaned, float needle/valve replaced, gaskets replaced. Carb set to two turns off level as per instructions.

* Points adjusted and double checked - all correct.

* Water found in distributer cap and over points (left in rain for short time *ahem*) - this was dried out and WD40 used.

* Water removed from each of the HT caps on back of dizzy cap and made firm.

* Engine idles fine, speed adjusted as per manual.

* As soon as throttle pedal engaged engine bogs down and dies.

* Replaced dashpot oil with 3-1 'handy oil' (very light) and got same result.

* Replaced dashpot oil with clean engine oil and got same result.

* Each time engine would only increase speed if choke fully engaged - however each time with choke out any further action on throttle bogged the engine again and would die instantly.

*Increased mixture setting on jet - enriched mixture one turn at a time upto approx 8 turns - no change.

Only way I can increase engine speed without bogging down is unscrewing dashpot plunger and holding it on edge of dashpot and pushing down hard while operating the throttle.

Float valve is operating without washer to raise fuel level.


Any non-standard parts that might be involved with the problem?

Nope.

Edited by Disco Dan, 11 January 2009 - 01:09 AM.

[Disco Dan]

Searched and found something about vacuum advance?

I removed pipe from carb and while it was still attached to dizzy - I sucked on it but nothing happened.

[Disco Dan]

Oh forgot to mention:

Wire came loose inside dizzy - the black one that attaches to points. It was wiggling and causing engine not to fire up - soldered it up.

Could the other wire (orange) one be causing this latest problem?

[philc]

could do with a serivce, new plugs, cap, leads, points and condensor and coil if needed

[benb12]

Perhaps the dashpot oil is too thin?

[Kernal H]

Have you taken a look at the spark plugs? They could well be sooted up or not sparking correctly which means that they can't handle any acceleration. Give them a clean and see what happens. Have you also checked the condensor and points. You need a good spark to run!!

[Disco Dan]

New engine oil/filter and new plugs prior to the non starting.

Will check plugs and try again.

Points were cleaned up with a bit of emery paper and adjusted correctly.

Yes to me sounds like the dashpot oil is too thin - but I do not have anything thicker than engine oil ! ! !

THank you!! 1am here, will check in the morning!!

[ANON]

dwell angle and check the throttle spindle for wear

[Disco Dan]

Points checked again, and spark plugs cleaned up. No change. Even put old plugs in and tried that.

[Chimp89]

I have the same problem. Have tried everything i can think of and read as much as i can, still can't fix it!

Also mine idles at about 1200 rpm, even if i unscrew the idle screw completely!

Don't think that's linked to the problem in any way but may as well throw it in while i'm at it!

Thanks, Christian

Also, forgot to mention i recently put a stage 1 kit on it and that seemed to make the bogging down more significant. It's as though it's running on 3 cylinders up to about 4k rpm, then runs fine to red line. The only way i can stop it is by pulling the choke out fully.

Edited by Chimp89, 12 June 2012 - 08:39 PM.

[jamiestevenbell]

I had exactly this problem and mine turned out to be the coil breaking down

[hector193]

Did you ever find a solution to this?
Im having the same problem!