Logo
FULL SITE MENU

Older BF75 carb problems...

sandkicker

sandkicker

Outstanding Contributor
Ok... I got tired of fiddling (several bouts with seafoam) with the engine and sent it to my mechanic, where is sat for several weeks (OK, its peak "season") and was returned with a $100 repair bill. I got it back and it ran Ok for a few mins and then stopped. Mechanic won't even look at it until November... It appears to be a float level/valve problem, as when I pump the bulb until its hard and then open the carb drain, a small amount of gas flows out and then stops but the bulb is still hard and won't pump further. Removing the fuel line from the carb allows gas to be pumped thru the system up to the point where the hose attaches to the carb. I replaced the fuel line and then pumped it up and then took the carb off and left the fuel line on and removed the bowl. Very little gas in the bowl. I then pumped the bulb and some gas squirted out and then stopped with bulb remaining hard (bowl removed, carb in normal orientatin!!!).
Since I was charged for a new float needle, I am assuming that the float level/drop settings are wrong. I know this info is in the OEM Honda shop manual, however, I moved recently and can't find my copy of the manual.

Anyone know what the level/drop measurements are supposed to be for this engine?
Its a 150 series, 7.5 HP...

TIA.....
 
I am not sure what the 150 series is.

There are two vintages of BF75. The older vintage has the carburator that looks like it is sitting on its side with the intake at the top. If you have that one, the height is 7 mm. I do not know of any drop measurement.

Also, I think it has a linkage from the fuel connector that activates a fuel cutoff on the carburator. Make sure that is working correctly.

If you have the vintage that the carb sits normally (float bowl on bottom) then the float height is 9.85 - 10.15 mm. I do not know of any drop measurement.

It sounds like you are on the right track.

Mike
 
Thanks for the quick response... I have the second one, i.e., the one with the bowl on the bottom and no cut off link. As I recall, that measurement it taken with the carb tilted and that distance is from the carb housing to the far end of the float when the float tang just touches the spring loaded pin on the valve? Or do I have this confused with another carb I've worked on over the years... Its been a few years since I even had to look in the Honda manual.
 
You remember right. Generally, if the float is parallel to the base of the carb when you turn it upside down, it is real close.

Mike
 
Well... that fixed it. Starts and runs just like a new motor now. The float height was waaaay of. So far off that I thought I was measuring it incorrectly. Your quick check, i.e., float horizontal was the sanity test I needed to make sure I was measuring it correctly. Float height as found was 16.5mm !
Now set to 10.0... all is well. Again thank you for your quick reply and the sanity check measurement.
 
Glad the fix was easy. I hope you don't have your mechanic rebuild a motor if he does not know what the float height should be.

Mike
 
hondadude said:
I am not sure what the 150 series is.

There are two vintages of BF75. The older vintage has the carburator that looks like it is sitting on its side with the intake at the top. If you have that one, the height is 7 mm. I do not know of any drop measurement.

Also, I think it has a linkage from the fuel connector that activates a fuel cutoff on the carburator. Make sure that is working correctly.

If you have the vintage that the carb sits normally (float bowl on bottom) then the float height is 9.85 - 10.15 mm. I do not know of any drop measurement.

It sounds like you are on the right track.

Mike
Click to expand...
What do you measure from on the 7 mm vertical carbs.
 
hondadude said:
I am not sure what the 150 series is.

There are two vintages of BF75. The older vintage has the carburator that looks like it is sitting on its side with the intake at the top. If you have that one, the height is 7 mm. I do not know of any drop measurement.

Also, I think it has a linkage from the fuel connector that activates a fuel cutoff on the carburator. Make sure that is working correctly.

If you have the vintage that the carb sits normally (float bowl on bottom) then the float height is 9.85 - 10.15 mm. I do not know of any drop measurement.

It sounds like you are on the right track.

Mike
Click to expand...
What do you measure from and to on the 7 mm vertical carb?
 
Back
Top