engine help no power

I am having trouble with my engine loosing power then cutting out, this only happens after driving for about 3-4miles so the engine is fully warmed up when it happens. There is oil leaking from around the rocker covers and pushrod tubes, this appears to become worse when the engine heats up. Leaving a trail of oil drops every 2m or so when driving and puffs of black smoke when it hits the exhaust, parked up oil loss is minimal. My question is do you think this could cause a pressure loss sufficient to prevent proper oil circulation through the engine hence distinct lack of power shortly before cutting out? The timing may also not be perfectly setup yet but the engine performs well over short distances so I don’t think this has much to do with it. Any suggestions greatly appreciated.

Check timing and check the choke is coming off fuly.
Give it a full service then see how it goes.

Its a bit difficult to check, but I think its worth checking your fuel pump. If the push rod sticks a bit then it can lead to these symptoms.
Remove pump and check it looks OK. Check the push-rod, sometimes on an old high milage engine it may have a bit of carbon or gum on it, clean it till it shines and check it is not sticking in its guide.
To check this properly the next time it happens, switch of the engine immediately and remove to top cover of the carb and see whether the float bowl has the correct level of petrol.

Alan - 2008-02-03 11:07 PM

Its a bit difficult to check, but I think its worth checking your fuel pump. If the push rod sticks a bit then it can lead to these symptoms.
Remove pump and check it looks OK. Check the push-rod, sometimes on an old high milage engine it may have a bit of carbon or gum on it, clean it till it shines and check it is not sticking in its guide.
To check this properly the next time it happens, switch of the engine immediately and remove to top cover of the carb and see whether the float bowl has the correct level of petrol.

Would agree with Alan. First option would be fuel pump. If you dont have a petrol filter in the engine bay fit one, the clear type, so you can check if it happens again if there is any fuel in in. My brother had a similar problem, the pivot point had worn in the pump and it became less efficient when it heated up. I would fit some new rocker cover gaskets, check the clips are given sufficient pressure ( yo9u should need to lever them on and off with a screwdriver), if not bend them a bit or replace them. Puch rod tubes can be replaced in situ with the srung scat one, but there a really tight fit on a 1200 due to the shorter width of the engine. Thats why I’ve not done mine yet.

Ditto to Keith’s comment above.

The leak from the valve cover should just take a new gasket.
While you are there, check the valve clearances or get someone else to. Old beetles have a much shorter time between services than modern cars and need regular checks. Oil changes are supposed to be every 3000 miles.

However, the pump is a possible. This caused me a lot of problems in the past. The pump seemed okay, and I even fitted new seals but the pivot hole had worn into an oval shape, so the rocking piece didn’t travel as far. This resulted in the car being very hard to start when hot as the pump didn’t deliver enough fuel on the starter. Once or twice it cut out after a mile or so but could be restarted by hard downshifting before it stoped.

All good suggestions so far. Here’s another.

Beetle engines often leak oil, they are not built like the engines in modern cars and there are many more places for it to escape from. Not a good thing but doesn’t necessarily mean that it’s gubbed.
You say that the power loss happens 3-4 miles after a cold start. Beetle engines are very sensitive to certain systems working correctly, esp in cold weather. Your engine may not be warmed up at all and you be be experiencing carburettor/inlet manifold icing which would give exactly the symptoms you describe.

Check that the thermostat is in place and working. If it has broken or is missing, the engine will take a LONG time to get up to correct working temperature.

Check that the preheat pipes on the inlet manifold are carrying heat all the way from one side to the other. This pipe carries exhaust gasses up against the inelt manifold in order to keep it warm but they get blocked with carbon deposits over the years and stop working.

Check that the thermostatically controlled hot-air valve in your air filter box is working. This puts hot air into the carb in cold weather, also to keep the inlet system warm and fight carb icing… but the valve and the vacuum-operated flap both commonly fail with age.

Keep us posted!

Nick - 2008-02-06 1:16 PM
…You say that the power loss happens 3-4 miles after a cold start. Beetle engines are very sensitive to certain systems working correctly, esp in cold weather. Your engine may not be warmed up at all and you be be experiencing carburettor/inlet manifold icing which would give exactly the symptoms you describe…

That’s what I was thinking too! :thumb:
I bet the manifold riser’s got blocked or a warm air supply to the air filter has failed.
Bloody hard to get hold of an IMDU these days, but they did a great job on my single-carbed V-dubs!