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MG MGB Technical - Fuel Overflow--Follow up

Still having flooding problem. Have disengaged the fuel pump, run the engine until fuel in floats is gone. Replaced the fuel filter. Restarted with fuel pump engaged. Thought it was going to work, and then major flooding again. Have tried to purge the system several times, with the same result.
If I turn the key to on, but not to the start position, the pump will keep running, and eventually start running out of the carbs.
I disconnected the inlet line to the carbs, connected a pressure gauge, and plugged the end. Turned the pump on, and the pressure reads about 1.5 lbs. So that looks good.
Guess I'm looking at replacing the float valves?
Thanks for the suggestions on the previous thread, and for any addition hints from this one.
Pat
Pat

Pat - Check the floats themselves for flooding. If they are full of gas, they won't shut off the valve.
Good luck - Dave
David DuBois

Pat;
David makes an excellent point. If floats are not filled with fuel, you need to replace the needle/seats.If they are, replace the floats.
I use Gross ball seats in my big Healey with good results as long as an inline filter near the carbs is installed. Some on this board have had problems with Gross valves, but I have had good results for the last two years. They are available from Moss & others, or better yet, Joe Curto in NY.

Pete 76 B w/ HIF4's
Pete Haburt

David & Pete,
Thanks. My car has the HIF4s also (73 BGT). I have not disassembled anything yet, but I would guess the floats are full (from the way the car starts & runs with pump disengaged).
Can you check the floats and/or valves without removing the entire carb assembly? Would like to minimize that part of the job, if possible.
If not, will probably have to wait till the "long winter's nap" to do a complete job.
Thanks again,
Pat
Pat

Pat - A friend of mine replaced a float in his HIF carb while it was in place, but it was quite a job. To get at the needle vlave would be an exercise in contorsionism (sp?). I think that taking the carbs off for disassembly and inspection would be the best bet. Good luck - Dave
David DuBois

Pat; I agree with Dave, I wouldn't even think of trying to check the float valves on HIF carbs without removing them from the car. You should be able to get them off in about 20 minutes or less. I did have some problems with Grose Jets in the HIF carb, the HIF requires a Grose jet with a smaller ball and the ball tends to stick if the car is not driven daily. In my case it stuck in the closed position with the float chamber full of fuel so the car would start and run great for two or three minutes until the rear carb went dry and shut down the two rear cylinders.

The main disadvantge of removing the carbs to repair them is you will need to recheck the carb sync, but it is so much easier to inspect and service them off the car. You should be able to do the job in 2 or 3 hours or less the first time. Good luck, Clifton
Clifton Gordon

Pat

One of my HIF carbs had an overflow following replacing the engine on my 73B - I guess it didn't like being off the car for a couple of weeks. I bit the bullet and purchased a pair of carb overhaul kits which included new float valve assemblies. This cured the problem and I learned a bit about SU carbs - in this case I found the Haynes manual particularly helpful. The only caveat I would make would be to study the linkage, cable and spring arrangement prior to removal - if possible take a photo since it helps on reassembly.

Good luck,

BarryQ 73B
B.J. Quartermaine

Pat,

When you do have time to take the carbs off be sure to:
- replace the float pivot pins as well as the floats.
- check for casting flash on the walls of the float bowl that may interfere with the smooth operation of the floats.

My hard learned 2 cents...

Tom 73B w/*^%$!^& HIF carbs
Tom

Way back in 87 or 88 I had the gas tanked lined on my B. I understand they sloshed a solution around inside so it coated the tank. I have no idea how old the tank was at the time but there was no visible rust. At any rate here it is 2002 and the tank is still in great shape. Every time it is off, for one reason or another I wash it out to get any sludge etc out and repaint the outside.

Bruce

Bruce

Thanks all,
Good suggestions, and all seem to be consistent--guess I'll have to place my parts order and try to schedule some time this fall.
In the meantime, I might even look around for a spare set of carbs.
Thanks again,
Pat
Pat

This thread was discussed between 22/09/2002 and 26/09/2002

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