Honda BF 90 carb question

[Kurt.Z]

hello, I have a honda BF 90 year 2000, it started running poorly so i pulled the carbs to do a cleaning. before pulling the carbs the motor would not start unless i gave it full choke and 3/4 throttle. So i changed all fuel filters, all fuel lines from the tank pulled and cleaned the carbs. after reassembly the motor now starts with no choke but must still have 3/4 throttle to run. i was wondering if the slow jet emulsion tube had a passage way all the way through from one side to the other because i didnt see one but i did clean all side ports and through the center as far as it would allow which was not all the way from one end to the other. i love this motor but its making me feel like its time for EFI. thanks to anyone who can shed some light on this. Kurt

 

[Milgrip]

I don't know if the emulsion tube has a passage way all the way through, maybe someone else can answer that, but it is not unusual to have the carbs off more than once to get them functioning as they should.
Can you get hold of an ultrasonic cleaner?
Always best to check valve clearances and spark plugs before messing with carbs and once the carbs are clean you should balance them.

 

[Kurt.Z]

my mistake, i did change the plugs first. and then resorted to the carbs. im looking into a set a vac. gauges to set them but with the non idle issue i cant do that until i at least get it running. the carbs were full of white powder. i drained them at the end of the year but the ethanol gas seemed to still lingered and got me. thanks for the reply.

 

[BruceK]

Uploaded your carb manual to wetransfer as it is bigger than the size allowed here : 2014-08-21_141611_ml.repaw05k.marine_carburetion_manual_-_chapter_7.pdf

I'd suggest your pilot screw is not set correctly

 

[Kurt.Z]

Uploaded your carb manual to wetransfer as it is bigger than the size allowed here : 2014-08-21_141611_ml.repaw05k.marine_carburetion_manual_-_chapter_7.pdf

I'd suggest your pilot screw is not set correctly

Thanks! The only thing that I didn’t pull apart on it where the air idle mixture screws, I Will solder off the glued on caps take them out and clean them. I’ll be sure to count how many rotations that they are backed off before I take them out. Thanks I hope this works

 

[spannerman]

Ifyou had white powder then its a sure bet the emulsion tube is blocked, we see this on literally dozens of outboards after a winter in the garage, we use am ultrasonic cleaner which is brilliant for this type of problem. Otherwise its carb cleaner spray and an airline and a set of jet cleaning tools.

 

[Kurt.Z]

Ifyou had white powder then its a sure bet the emulsion tube is blocked, we see this on literally dozens of outboards after a winter in the garage, we use am ultrasonic cleaner which is brilliant for this type of problem. Otherwise its carb cleaner spray and an airline and a set of jet cleaning tools.

Ifyou had white powder then its a sure bet the emulsion tube is blocked, we see this on literally dozens of outboards after a winter in the garage, we use am ultrasonic cleaner which is brilliant for this type of problem. Otherwise its carb cleaner spray and an airline and a set of jet cleaning tools.

question? does the emulsion tube have a passage way in the center that runs the whole length of the tube or does it terminate about 3/4 of the way ? i cleared the side holes but i cant tell if there is a passage all the way through the thing and i am thinking about pulling it all back apart to see if i missed something . thanks for your help.

 

[Milgrip]

The white powder as I understand, is the result of the innards of the carburettors degrading due to fuel left to evaporate in the float chambers and water contaminated fuel probably made worse by ethanol in todays fuel. No matter how many times you clean them the white powder will return. You are fighting a loosing battle.