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Could anyone tell me why I have fuel dumping out of the bowl vent on my Nikki carburetor modified while the car is running? Are my bowls getting too much fuel
how long ago since the modifications? have you been driving with the modified carb, or is this your first use of it?
any change to fuel pump?
for me, in general, when i hear stuff like this, i think of:
1. way too much fuel pressure
2. sticking or otherwise malfunctioning floats, or
3. an issue with the gasket under the carb.
1 and 3 are fairly black and white, so they are pretty easy to check. however, they also (seem to me to) tend to be less common than #2.
When I rebuilt the carb I set the floats to FSM specs. Carb is de rats nested. Runs but saw fuel coming out of the vent. Capped off the vent solenoid. No longer works pulled the guts out and filled with jbweld. When at idle car throttles up OK but saw fuel in the secondaries when I shut it down. Car has not driven since I rebuilt the whole car. Still working out the bugs
I think the part on the driver's side of carb is called the air vent solenoid. That's what I plugged per the instructions from this site on how to strip a nikki
"Another possible cause is the float bowl vent solenoid. If this is not functioning or stuck closed, the carb will easily overfill and flood the engine. Though it really only affects things while running and is not a cause of flooding after shut down because it is designed to spring closed when not connected to 12V."
When I took the carb off yesterday the bowls were almost full to the top on the sight glass. Do I need to readjust my floats to let less fuel in. I have no vent solenoid it's been plugged
when you rebuilt the carb, did you re-use the original needles and seats or did you use the ones from your kit? if you used the ones from the kit, did you happen to keep the originals?
I reused the needles and seats that were in the carb.UT that is not to say that the previous owner did not try to rebuild it.Which I think at this point he did because there were new gaskets when I got the car even though the car was all in pieces so I think he might have tried to rebuild it
How do I check to see if the restricter is in the fuel return line. I had to replace the two lines in the engine bay cause the old ones were rotted out. It is very possible that the PO put new needles and seats in but didn't finish the rebuild cause when I got the car the carb was in its three individual pieces and the floats were all out whack due to the carb sitting on the float side. When I rebuilt it I left all the needles and seats in it after cleaning it and just replaced the little check *****. I reset the floats to 2 5/8" with the little ruler that came in the rebuild kit. Like I stated earlier in the thread when I took the carb off I'm pretty sure the sight glasses were full to the top with fuel
The vent must be open so that the bowl is vented to atmosphere in the top of the carb. That is probably what you did, if you followed the directions properly. The Nikki stripping directions I just looked at were pretty vague although technically correct. The pic shows where the bowls vent to atmosphere in the air cleaner space. Make sure the channels between that port and both bowls is open. If not flooding will occur.
Not sure if you worked out the carb issue yet, but here is a pic showing the bowl vent flow path that has to be open to atmosphere inside the aircleaner space.
Haven't done this myself but I've read here that you can smooth down the needles and polish them and likewise for the seats. Apparently the aftermarket needles are a bit rougher and that can cause them to stick when trying to seat.
04-24-24, 02:49 PM
