my 2L air-cooled engine in a buggy with electric fuel pump and vacuum timing adjustment most recently showed the following problem. When driving under sustained load uphill on the road [between about 60% and 80% throttle] after a while [about 500m to 1km] the motor quickly but not instantly looses power and misfires. I can nurture it on, it will first stop misfiring but lack power and finally settle down. I can reproduce this without fail. I thought valves overheating under load, checked the clearance, all within 0.15 to 0.2mm or more. Adjusted, no change. Could it be the fuel pump not providing sufficient fuel under sustained load? It has no problem supplying short spurts. Does it sound familiar? What else could it be?
johannes ·
I found the problem. I am a bit embarrased to admit, it was the fuel filter! I checked the flow out of the hose to one carburator. It was very weak. The carbies were slowly sucked dry under "prolonged" load, mixture lean, misfire, ...Changed the filter, which is at a stupid spot, and the flow was much stronger. Test drive and the problem is gone. Will place the filter at a more accessible spot. Might be useful to remeber.
68AutoBug ·
well My fuel filter is under the fuel tank...
I just replace it every year..
Lee
VWCOOL ·
You only need one filter and DO NOT EVER install it after the fuel pump. Put it under the tank or near the gearbox. Some people say don't install it in the engine bay, but I like it there (before the fuel pump, of course!) as it is in view
donn ·
must be that time of year, had a simillar problem since early in the year and even though I have replaced the coil and condenser, cleaned out the tank and the fuel filter the problem persisted, last weekend after thinking I had solved the problem I took the buggy for a run and got caught halfway across a bussy intersection. Stuff this says I, call the NRMA, bloke agreed with me that it seemed like a fuel problem and said he would check the fuel filter anyway, couldn't even blow through it (how embarred was little old me), stuffed if I know what's blocking it but I can't clean it out, took the cartridge out and off it went. So now I'll drain the tank and fit a new filter cartridge and hopefully all is good.