Logo
FULL SITE MENU

2003 honda 50 hp bf50 carb problem

A

artie717

New member
does any one know how many turns the fuel screws need to be set at i had to grind off the tab to adjust them,after i cleaned the carbs the motor idles fine and runs perfect out of the water but under a load it will not make the transition onto the main jet it just dies off.i took the carbs back apart to look at all of the tubes and the main jets float level all fine also ck the dash pot it pumps fuel to all of the carbs when accelerating,i was just thinking that maybe it is pulling air through the pilot screws ? i did ck all of the basics like t-belt and compression both o.k
 
Re: 03 honda bf50 carb problem

I'm not the big expert on these but I see you don't mention synchronizing the carbs. I believe that these engines are pretty sensitive to having them synched correctly.
 
Re: 03 honda bf50 carb problem

yes they where done with mercury gauges it did seem like the center carb was harder to get in the range
 
it seems to have a very rough idle at 1 turn i have them out 2.5 with the carbs syncronized,i just got done doing it i took them apart again just to make sure i did not miss anything it has a perfect idle just like before just would not make the transition to the main, circuit i could choke it or cover the air box and it would almost ack normal could the vacumm vale that shoots the air to the emusion tubes be miss adjusted?or would that just cause a flat spot i am going to put it in the water in the a.m.i did have a hard time getting the center car to sync i am a bike tech and not used to 3 cylynders it has good compression and i can shut it off with the pilot screw,new plugs also
 
it might be a 04 i will ck it will not run at 1 turn out,2.5 seems perfect i took it out on the water today and same problem idles smooth will move the boat fine untill you try to accelerate .i pulled the fuel lines to make sure it was getting enough fuel it was fine it seems like all cylinders not just one carb i also adusted the dash pot with no change it feels just like the main jet is plugged or to small.i can tape off half of the carb throat with duct tape and it will almost run normal.i am going to take them apart again and look them over again they are very simple carbs to do i must be missing something.i would think maybee one of the tubes has a crack but it is all cylinders not just one,i was able to sync the carbs and i can shut off each clylinder with the fuel screws so i thing the primary part is fine.i don't have a manuel on this.i think i could put a bigger main jet in and fix it but it ran fine before, are there different air box to carb gaskets i did change it and there are 2 air bleed holes in the carb mabee the gasket covers one ?i think that my original gaskets where individual ones and the replacement was one large gasket they told me that this was a updated gasket?
 
When you balanced the carbs, did you pinch off the three hoses http://www.boats.net/parts/search/H...3400001 TO BAZS-3499999/CARBURETOR/parts.html #24.

Two go between the carburators and one goes from the top carburator to somewhere I do not remember. If you do not pinch them off, you can not balance the carbs properly.

You will probably have to increase the idle a little to keep it running when you do pinch them off. Once balanced, then reduce the idle to where it should be.

As for the muffler plate gasket...it is all one piece. http://www.boats.net/parts/search/H...1 TO BAZS-3499999/CARBURETOR ASSY./parts.html part #16

This has never been changed, as far as I remember. It is one piece, as you can see. It may be possible to put it on wrong, but only if you ignore the two positioning pegs on the muffler plate (part #30). I would relook at that.

Also, make sure that the base gaskets are oriented properly so they are not blocking the opening to the intake manifold. Recheck the orientation of the intake manifold gasket. Although, I think that one is pretty obvious if it is on wrong.

Mike

If it ran fine before, do not change any of the jets unless they are damaged. It will just be compensating for something else and could hurt your motor over time.

Mike
 
no i did not pinch off the hoses they are the ones that go to the dash pot?thats why i had a hard time getting the to sync it took a long time to get them even and they where at a low rate i thought,but i was able to get the even.do you think that could cause the problem i am having?it idled perfect ran smooth you could not even tell it was running in the water. i am going to look at it again on monday i need a day of rest,thanks for all of the info i will let you know how i make out!
 
i just looked at the link you sent of the tubes my carbs don't hae them i think the motor is a 03 i will ck the vin asap i have the accelarator dash pot
 
A frame serial number will give us the info we need to know for sure.

Generally, if you are having trouble syncronizing the carbs, the slow jet emusion tube (the skinney tube up through the carb), may have a small crack in it or it is not thoroughly cleaned.

By the way, all the 50's have a dash pot (it is for acceleration and deaccelertion).

Also, if you have to turn the idle mixture screws out significantly further than the book calls for, there may be other passages plugged up yet.

Let's see what motor you have before we go down too many roads.

I think you said you do not have a manual. I strongly recommend getting one from Helm. If you want to concentrate on carburators, Helm has a great Honda carb manual that gets into nausiating detail and colored pictures of fuel flow, trouble shooting, cleaning, etc. Its number is TM044. Helminc.com http://www.helminc.com/helm/result....tegory=9&Keyword=&Module=&selected_media=&sku=

It is about $40. But well worth it.

Mike
 
Last edited:
thanks i will pull them apart and try to look at the tubes for the primary.i will look at the vin in the a.m,hate to buy a manual they seem to simple i have done hundreds of bike carbs i am just missing somthing can the emulsion tube go in backwards?
 
Maybe...I never tried.

Make sure the skinney idle tube has a little lube on the o ring so that it goes seats all the way. The rounded end of the larger tube goes in last. Both tubes will be flush with each other before you put the screw plug in the end.

Mike
 
http://www.marineengine.com/boat-fo...ng-2003-BF-50-Help-please&p=325060#post325060

Hey Artie,

would you look at this thead and see if my full open throttle in gear but not started is about what yours is? If not could you take a photo of yours and send me a pic and take a pic of where the throttle cables are so I can see how they are adjusted beside the engine there? I might be able to adjust mine off your picture.

Thanks for any help you might provide,

Chris
 
just looked at the vin number is bazs -3304347 bf50a there is a 3a on the sticker sticker on the side also.is there any o-ring or seal that gos on the lrge tube that go's up into the carb.i did not see anything on them ? i am taking them apart again.i am thinking about getting the new primary jets but i don't see any cracks,but my eyes are goin south also!!!i can get them for around 14.95 i am just no sure thats goin to do it i can spray cleaner through them and see it come out the other side,i can also hold them up to the light and see through them.i would think that mabee there was another problem like a failsafe or somthing but i can tape off the carbs and it almost seems o.k! i just looked at the primary tubes again i think i might see a crack in the center carbs tube way down at the bottom i am going to replace them all i can get them tommorow would this couse the problem i am having?that was the car i had a problem getting it to sync,would one primary tube afect all cylinders off idle?
 
Last edited:
There is no seal on the larger emulsion tube. Only on the skinney one. If you can shoot and see through the little one and there are no cracks, they should be ok unless you damaged them getting them out. If your idle is good, they are probably ok.

Mike
 
i think there is a crack in the one on the center carb i will look with a magnifing glass ,i was thinking that mabee if it was pulling to much fuel when i sync the carbs they are off! but could that cause the issue i have ? theres not any else that i see.i will know tomorrow.
 
Do not know if that is causing your overall running problem.

It is a 2003 (by your serial number)

You may want to recheck the timing marks. Normally, if timing is off by one notch, the idle gets messed up too.

Also, you said that you checked compression...was it around 199 psi?

You said that you can tape off part of the intake and it will run almost good. (Is that good english?)
One trick, that you may have already done....remove the choke linkage that runs from carb to carb (after you start the motor). Then operate the choke on each carb individually. If the motor picks up on one or two of them, that is where you focus your investigation...

Mike
 
190 190 195 on comp.i am going to put the pilot jets in tomorrow a.m i will try to choke them off one at a time to see if i can narrow it down i did ck the belt it looked fine i lined up the t pointer with #one @tdc i did not see a mark on the flywheel side do you have to pull the flywheel to see the mark?also is there any kind of timing retard or a failsafe mode that could maybe cause this
 
When you have the cam pulley T aligned with the T pointer on the top of the power head, there is a T with a line next to it engraved on the outer edge of the flywheel. It should be be aligned with the I on the engine hanger boss. It is on the port end of the hanger bracket.

The spark advance is electronically controlled by the ECM in conjunction with the speed of the engine.

I am out of town and may be occupied in the evenings, so my next reply may be a little delayed.

Mike
 
i just finished puttng in the pilot tubes (jets)was able to sync the carbs perfect and it ran perfect !! it still seemed alittle rough at idle in gear in the water but i thing it is becuase its a 3 cylinder .i can not beleave that the tiny crack in one tube made the engine not accel it was the center carb that had the crack i missed it twice i really need to get glasses!!it looked like a scratch. i really appreciate all of the help!!
 
Back
Top