BF75 wonbt idle

"Ok here is the story so far..

"Ok here is the story so far... Last year motor ran like a top. One or two pulls it started, a min or so on choke, idled and ran in gear like a champ. This year. Started after winter on third pull...ran OK for 5 min shut it down. Two weeks later would not start.

I started checking and found no fuel to carb. EVentually traced it to lots of gunk in carb plugged filter. Liner of aftermarket fuel hose was solvent in ethanol ( an old post of mine). Cleaned carb out, found out it was overheating, changed T'stat and gaskets ( another post) changed out all the internal hoses. It would start but could not get it to idle. Took carb apart again, soaked in alcohol, blew out all passages and jets ( after taking them all out) reset float level ( I think the book is wrong @ 10mm). Checked fuel pump, reset ignition timing, checked spark advance mechanism (CDI ignition serial #150xxxxx) and its OK. New plugs, properly gapped. Fresh gas. Engine is harder to start than usual ( 5 or 6 pulls!). Throttle set per shop manual. Idle mixture screw 2 turns out. Idle stop screw, 2 turns out from full closed. It will start and race with choke pulled out, cen get it sort of idle playing with choke. After it warms up, if you try to slow engine down, it goes from very very fast idle (probably 2000 rpm...sorry, no tach) to stopped dead. Plugs (new) are black.
It appears to me as if the idle circuit is totally non functional even though I poured alcohol thru it and blew it out several times.
Really tried to figure this one out myself, but heve run out of ideas."

"Also, to eliminate float leve

"Also, to eliminate float level as a problem, I disconnected the tank, started and ran it...same problem."

sounds like u need to reuild t

sounds like u need to reuild the carbs again
do not soak the carbs!

"On your 10mm float level, set

"On your 10mm float level, set it without compressing the little spring button on needle valve.

Black spark plugs indicate excess gas, float level could be too high. Honda Shop manual calls for 9.85-10.15mm or 0.388-0.400 inch."

""Just"... Was afraid

""Just"... Was afraid you were going to say that ... Silly question, why not soak carbs?

Found the description of the idle circuit in the back of the Honda shop manual. Its a fairly tortous path, even with the blocking screw removed. Any hints on cleaning it out? Already used compressed air...etc..etc...

"Pilotart"..float level presently at 15mm. At 10, the float needle would not drop, If you blew (by mouth) in the fuel port, no air got thru the fuel line. At 15 mm the float exerts a slight bit of downward pressure on the wire "hoop" and pulls the needle valve open. Would replace the float/needle but neither Honda dealer near me, has one in stock and I've had not so good luck getting parts that are supposed to be "just a few days". The engine is just used to get my 22 ft sailboat in and out of the marina. Rarely run the motor much above half throttle. A new float/needle will have to wait untillater in the season... I can and do sail until election day ,so I've got more boating season to go."

marine carbs have a special co

marine carbs have a special coating
you can do the quick ones but the overnighters or long times is not good

Thanks... Should be able to ge

Thanks... Should be able to get over to the boat tomorrow....One More Time !.... funny... that's the boat's name!

let us know
im going to b bus

let us know
im going to b busy these next 4 days

"Update...

Last night I too

"Update...

Last night I took the carb apart again. Did all the dip and blow out thing. Then I realized that there was one more passage/jet. There is a screw in the carb body near the idle mixture adjustment screw that covers a passage with a VERY small jet. I had blown this out several times before. According to the shop manual this is part of the idle circuit. I took a single strand of a 22 AWG copper wire (7x30)( i.e. one of the seven, 30 gauge strands that made up the wire) and after several failed attempts involving a magnifying glass, flash light and tweezers was finally able to get the wire to pass thru the jet. It did not initially go all that smoothly, but after several passes it did. I flooded it with alcohol and blew it out from the top (while working over a paper towel) and the tiniest bit of crap blew out thru the main jet passage this time. I used 22 AWG copper wire, not steel as the copper is softer than the brass jet and would not damage it. Next step, install carb and hope..."

good job!

good job!

"OK... went down to boat, re-i

"OK... went down to boat, re-installed the carb. Same problem! Got really upset and frustrated.

So, I got a piece of 30ga wire and ran it thru the idle metering jet(again)... except this time I left the carb on the engine with engine tilted up and turned to starboard (NOT FOR THE FUMBLE FINGERED!!).
Then I took a very close look at the screw that seals the idle circuit passage and its seat in the carb base. Not that dirty, but it could be cleaner...
Cleaned the screw threads, and the underside of the screw head and cleaned its' mating seat on the carb body. There is no gasket for this screw and I figured that a vacuum leak at this point would be a disaster.

Then for good measure... I took the red tube off of the "canned air" that I bought at Staples. Stuck the end of it in a can of carb cleaner and then put my finger on the top end of the tube. For those of you who still remember high school chemistry, this is called "pipetting". I stuck the other end of the red tube back on the air can and put the red tube down in the jet port as low and tight to the jet at the bottom as I could... two squirts of air...

Put the whole thing back together....SUCCESS!!!

Starts and Idles like a champ.

I have NO idea what it was that I did today that fixed it...its fixed!

Lesson(s) learned:
Nothing is too small to ignore.
It can't be too clean.
Canned air ROCKS!
Honda Shop Manual, while a bit "sparse" in spots is well worth the money (unless you like paying the shop $150/hr for their time!).
This site and the folks on it are a fantastic resource... Thanks again to all... especially "Just in time""

well sounds like the was trash

well sounds like the was trash in the carb still

i use the canned air and carb cleaner evry carb job