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Fuel Delivery Question

J Eade

Member
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My 64 BJ8 has two Fram clear fuel filters between the fuel pump and the carbs. One is located just after the pump, the other just before the carbs. The filters never seem to be full...the fuel level is about 1/2 to 3/4 of the filter's capacity. The car runs fine, but I would think that the pump ought to keep the filter full at all times - after all, it can't hold more than an ounce or so. I was considering cleaning the screen in the fuel pump, but then again "if ain't broke, don't fix it." Does this situation seem normal?
 
translucent filters give a confusing picture. They never look full. The glass type can be worse. I always recomend to not have any filters except the little screens in the carbs. No external filters has worked for me for 20 years, but then I have an aluminium tank.
 
The filters will trap air unless mounted vertically. If they are horizontal, the air pocket above the pipe level can never be purged out towards the carbs unless you have VERY fast fuel flow and even then its doubtful.
 
Does this mean that if you use an external fuel filter before the carbs that it be mounted in the vertical poistion? Because I am having problems in which when the car is hot the engine doesn't want to idle and dies. Then I have to depress the throttle in order to get it going again. Something else just occured to me. I have a clear glass fuel filter that is in the horizontal position. It it on the fuel line by the left front quarter panel. Do you think my reason for the engine stall is percolation? Does a glass filter absorb more heat then a stell one? Should i put a little insulation around it. You the know the type of stuff that you see for you pipes at home from home despots. What does everyone think


Thanks
 
I recommend that you test it again throughly. Gas up and do a pre flight check. Take it for a long pleasant meandering drive with out any particular destination. Start out first thing in the morning before the sun rises and drive till midday. Find a good place to have a bite of lunch and stretch. Use this time to investigate and identify an alternate route back home. gas up again and do a pre flight check. Return home and report back the test results.
 
[ QUOTE ]
Does this mean that if you use an external fuel filter before the carbs that it be mounted in the vertical poistion? Because I am having problems in which when the car is hot the engine doesn't want to idle and dies. Then I have to depress the throttle in order to get it going again. Something else just occured to me. I have a clear glass fuel filter that is in the horizontal position. It it on the fuel line by the left front quarter panel. Do you think my reason for the engine stall is percolation? Does a glass filter absorb more heat then a stell one? Should i put a little insulation around it. You the know the type of stuff that you see for you pipes at home from home despots. What does everyone think


Thanks

[/ QUOTE ]

It >>MAY<< be the hozinontal filter but I doubt it as the trapped air reduces the flow area but not to the point that the rate of use at idle will result in fuel starvation.

I had loads of problems setting my BJ8 to idle reasonably, some were too much wear on the distributor causing erratic timing, but another was the float chamber on the rear carb pressurising and flooding the carb. This was as the previous owner had put a plain fibre washer on the float lid nut rather than the one with relief notches as should be there. The result was there was no passage to atmosphere from the float chamber so when it got warm, vaporising fuel built up pressure and pumped more fuel into the back carb.

/ubbthreads/images/graemlins/england.gif
 
Well. I did get out in the afternoon. The started great and had a good idle. The idel was good until the car got warmed up and I had driven maybe 15 miles. The it was to low of an idle and the car would die. I did stop for gas and then when I started it back up, it started fine. Although it didn't want to idle and died. Other then that I put 50 mies on the car today. It ran great as long as I blipped the throttle at stoplights and depressed it a little to keep it going.
 
ynotme,
Ok so go back to the basics. Be sure. Valve train is adjusted, points adjusted, plugs cleaned and gapped. Set timing, check adjustment on carbs. If problem persists try replacing the fuel pump with a solid state version and make sure there are no leaks in the lines. Especially on the vacume side (between pump and tank). Clean out all fuel filter screens (your glass one and the stock screens in the banjo connectors on the car to carb link). Consider eliminating the fuel filter as a test. Hope this helps.
 
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I had loads of problems setting my BJ8 to idle reasonably, some were too much wear on the distributor causing erratic timing...

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This (distributor wobble) gets my vote as the most likely culprit when an engine won't hold it's idle. Anyway -- I always suspect the problem is 'igntion' before 'fuel' cause it so often is.
 
One thing about distributor wobble. You can't really tell by moving the rotor arm around. The best way is to hook up to a scope or meter and watch the dwell. If it is erratic, then you have a problem and even then it probably isn't the shaft bushes. They are separated from the upper plate and the shaft that holds the rotor. The basic bushes are pretty heavy duty and don't seem to wear. Instead look at the upper plate mechanisms.
 
I think the best place for a filter is between the tank and the pump--why risk getting crud in the latter? I have a plastic in-line Fram mounted horizontally in the left rear wheel arch--there's a bit of air but I've never had a problem with fuel feed, etc. BTW my SU fuel pump has a cleanable plastic strainer basket on the inlet side.
 
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