View Full Version : AD41B Hard Starting Air in system
11-10-2008, 09:40 PM
"I've got an air leak somewhere that allows my fuel filter to fill with air overnight. Unless I pump it up each time, the engine won't start and the frequent cranking has damaged my starter. I replaced the starter, but need to isolate the air leak. Any suggestions? The air could be on the racor filter side before the fuel pump or on the other side starting with the injectors. How should I attack this problem? Thanks."
Not sure, but remember...air rises, so your leak is below the filter.
12-23-2008, 04:22 PM
"Thanks Bob. So far I've rebuilt the Racor filter since I suspected it as the source of the air leak. I'll know soon if this resolves the problem. If not, then I suppose the fuel pump itself might be the culprit. It is the only thing lower than the secondary fuel filter on the engine. I don't see fuel leaking externally and it doesn't "appear" to be leaking internally into the crankcase. But the fuel has to go somewhere."
Negative, you don't necessarily need to have a fuel leak and probably will not have any indications of one. What you are experiencing is somewhat of a vapor lock. That's why it takes so long to crank...Air stretches, fuel doesn't. Any number of places air could enter the system, bad fittings, cracked lines, small pin hole, etc.
Good luck,if all else fails, try the ole soap test, soap everything down, pressure it up and look for bubbles.
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