FL250 Odyysey (Bighead Help)

[Badot]

Yep, the float should seal completely, even at a few psi. Generally speaking, carbs can hold a good bit of gas more than they're supposed to before they start leaking, this is likely why you thought it was working okay when you used a standard tee rather than the check valve tee -- it was filling up, it just takes a long time to get full and start dripping. If you want to confirm this, you can either wait and keep topping up the fuel line to maintain pressure if necessary, or drain and measure the contents.

From my experience with motorcycles, OEM needles lasted much, much longer than K&L brand... I imagine the same would be true for karts from a reputable brand.

Also, not sure how those carbs are built up, but if it has a removable float seat it could be an issue with the seal between the seat and the body rather than between the needle and seat.

 

[marty1]

Thanks Badot, The new carb kit should be in this weekend. It does have a seat so both will be removed and replaced. I will rehook up the clear test line to check for leaks. I gots my fingers crossed. I'll let you know how it goes. Thanks a bunch.

 

[marty1]

Still At It Replaced float seat, o-ring and valve. Pressure tested carb inlet hose to 4 psi. It still had a slow leak - took 14 minutes to leak down to 3 psi. Removed cleaned with Q tips and metal polish. Retested with gas line hooked up to fuel inlet. After 30 minutes it went down 2 inches. Keep in mind the original seat and float valve lost 4 psi in about 3 minutes and dropped 12 inches in 30 minutes of fuel test, so much better. Unfortunately after running a few minutes overflow fuel leak reappeared. Tore carb back down multiple time to recheck floats, height, ETC!!! but no luck. Does anyone have a good source for OEM original float seats and valves for a FL250 Honda Odyssey. The original seats have 2 holes and the ones off Ebay have 4 with smaller needles? I tried to see if leak was coming from seat or needle but being so close, I had no luck. You guys have been great and I'll keep plugging away Thanks again, Marty.

 

[Badot]

Is this the right one? http://www.partsnmore.com/parts/honda/fl250/?filters[fitting]=custom

Those holes in the side would make it pretty difficult to tell if it's leaking from the needle or seat. Generally if the surface that the o-ring on the seat and carb body is against is smooth and round, the o-ring isn't loose on the seat, and it takes a little pressure to put it in (compressing the o-ring) you won't have a problem with it though.

I assume that the holes in the side of the seat are after the point the needle seals. But I am curious, any idea what the heck they're for?

 

[Poboy kartman]

Is this the right one? http://www.partsnmore.com/parts/honda/fl250/?filters[fitting]=custom

Those holes in the side would make it pretty difficult to tell if it's leaking from the needle or seat. Generally if the surface that the o-ring on the seat and carb body is against is smooth and round, the o-ring isn't loose on the seat, and it takes a little pressure to put it in (compressing the o-ring) you won't have a problem with it though.

I assume that the holes in the side of the seat are after the point the needle seals. But I am curious, any idea what the heck they're for?

To let fuel out into the carb....so it doesn't have to flow around the needle....

 

[marty1]

Yes, Poboy is correct. The gas can escape past the needle or go through the holes up past outer seat. I rebuilt the 1977 carb last night. Did a pressure test to 4 psi and it lost a 1/4 psi in about 8 minutes. It is now hooked up to the gas line test and slowly dropping like the other. The difference is the needle was taped tight for the air test and the gas line is using float pressure. Both floats float have no cracks. Badot you said 3ft of line = 1 lb. I'm using 9 so 3lb. If the float is pressing up at 1 psi and the line down at 3 psi couldn't that open the needle. I'm checking into the original float/seats. A cycle website mentioned to try copper permatex on o ring for help sealing. Worried about gooping up carb but might be worth a shot. Marty.

 

[marty1]

I just invented a new test to run. I hooked a gauge to check fuel pressure to carb. I expected 5 lbs or more but with check Tee letting out pressure it stayed around 1 1/2 to 2 tops, between 1500 to 2500 rpm. So the new Tee probably won't make a difference. The ultra copper permatex around the seat idea came from guys with leaking carbs on their bikes. Same problem as me. The fuel tank is above the carb and if they don't turn off their petcock they end up with fuel on the garage floor. I wonder if they were running rich as well. I have never used the copper permatex, I assume it may remove easier so better for carb seat? Does this sound like something I should try? Thanks again, Marty.

 

[Badot]

If the float is pressing up at 1 psi and the line down at 3 psi couldn't that open the needle.

Yep, but that would likely be a pretty fast leak.

Using a pictures from google and incredibly conservative measurements:
I can determine the volume of the hollow pieces of the float are over .87in^3 each... assuming only a 75% efficiency would net a lifting force of .035 lbs
I can determine the mechanical advantage of the float is over 1.36/.35 -> 3.89.

Unfortunately I can't find a decent source for the diameter of the seat hole... so let's say it needs to hold against 3 psi and find the required diameter

.035 lbs * 3.89 would be .136 lbs on the needle. .136lbs/3psi gives .0453 in^2. Then sqrt(.0453/3.14)*2 = .24 in diameter. So basically, if a 1/4" drill bit won't fit through the seat, you shouldn't have a problem with the pressure opening the float.

I think the math is right at least

 

[marty1]

Wow Professor Badot, Something tells me I should've spent more time studying and less time shooting spitballs Got some more parts coming. Worse case scenario I'll just cement the carb inlet shut - that'll stop the leak.

 

[bighead]

I am still alive. Getting out of Ody for now. I got listed on Portland CL now. Looking t trade though.

I always used the T and never had problems. Make sure it on the right way. Do you have original carbs? Some carbs are set up for gravity feed and fuel pumps.

I just glanced thru the thread so not really up to date. Also much better carb guys than me here. Its basic carb but designed to run with that T. Guys that bypass it or go gravity feed have problems I remember.

Good luck

 

[landuse]

I am still alive. Getting out of Ody for now. I got listed on Portland CL now. Looking t trade though.

I always used the T and never had problems. Make sure it on the right way. Do you have original carbs? Some carbs are set up for gravity feed and fuel pumps.

I just glanced thru the thread so not really up to date. Also much better carb guys than me here. Its basic carb but designed to run with that T. Guys that bypass it or go gravity feed have problems I remember.

Good luck

Hey Bighead!! Welcome back!

 

[marty1]

Thanks for the reply Bighead Love your Odyssey rebuilds. Badot has been a huge help to me but feel free to chime in. Rebuilt carb with all OEM parts and boy what a difference The soaked spark plug is gone. I redid the hose test and it still drops an inch in a half an hour. This is way better than the other tests. When running, the float bowl overflow hose still slowly drips. But after 2 seats and needles, 1 permatexed o-ring on seat/needle and now a small leak on this new one - I'm out of ideas. Warmed up motor, adjusted rpm to 1500 spec and it ran good. I've noticed after motor cools, I have to bring idle screw up a 1/4 turn to restart because rpm seems to have dropped (1250-1300). Always something. Thanks to everyone who responded to my post, your help is very much appreciated. Marty.