BF 15 Carb Problem

"Have a late model BF15D , it

"Have a late model BF15D , it would not idle after the enrichment valve closed so we removed the carb. and cleaned out the circuit to the idle screw(it was blocked in the small tube that runs vertically)also checked the main jet, cleaned the inside of the bowl,checked the float valve:all looked good.Reinstalled, started engine, runs ok during enrichment, idles OK after enrichment ends is having very hard time reving up, will eventually run at wide open throttle. Noticed the accel pump? plunger never moves, is it suppose to?
Have done the online thing to access diagrams. Any Ideas?"

"RE: "Noticed the accel pu

"RE: "Noticed the accel pump? plunger never moves, is it suppose to?"

Yes, as you move the throttle."

"Thanks now the tough part. Wh

"Thanks now the tough part. When you take the carb apart, you are looking at the silver looking end of the accel pump plunger held in by a retaining screw. When you remove the retaining screw will the spring(hopefully) push the plunger out so you can clean it. If it is stuck hard any good advice to remove it?"

"Hi Russel,
Unless it is real

"Hi Russel,
Unless it is really stuck bad, you can tap the open part of the bowl on something fairly soft like a piece of 2X4, it should pop out. Sometimes I spray the thing with PB-Blaster and let it sit in the sun and that helps with the really stuck ones. When you get it out, you will see that the bore and the piston are scratched up pretty good. Just use some very fine (400) sand paper and clean them up. It doesn't matter if you create more clearance as they aren't very efficient accel pumps to begin with. What is more important is that the circuit is clear.

Also, locate the passage that that piston feeds to in the main carb body and, using the plastic "straw" that comes with a can of WD-40, make sure the accelerator tube in the muffler/front end of the carb throat is clear.

Here's how:

Use a pocket screwdriver and prop the throttle plate wide open by sticking it between the throttle lever and the carb body in the return spring area. When you spray the WD into the passage, a stream should shoot out of that brass tube through the carb and travel about 3 to 4 feet. If it doesn't, you need to "back flush" that tube by carefully placing the "straw" over the orifice in the tube and spraying. You can just see it thru the intake manifold end of the carb throat with the throttle plate propped wide open. Do a "back and forth" squirt flush until you are confident that the passage is clear. Watch out to not get sqiurted in the eyes as a plugged passage will build some pressure and that stream will get you if the passage is clear.

That accelerator circuit is sort an "Achilles heel" on those carburetors and the engine absolutely won't run right if that passage is plugged.

I know you said you cleaned the idle passage through the jet set but, while you have the thing apart, take out the brass plug that holds the jet set in place. Carefully remove the set and inspect the "O" ring at the top. They deteriorate and cause problems. While you have it out, take that WD straw again and stick it up into the passage that the jet feeds and spray in there, again with the throttle plate propped wide open, and check that the WD comes out of the idle and main passages in the upper part of the intake side of the carb throat. If all those holes are clear, then you should have a clean and flushed carb. Good luck."

"Thanks for the info, will be

"Thanks for the info, will be back at the dock this weekend for another episode of clean that carb.
Cruised some of the other topics GREAT Forum!"