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BF 25 Cold Start flooding.

D

DLC8113

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I recently purchased a 2006 BF25. (BATJ 1200600). I had to clean water out of rhe carbs and chose to replace the nasty slow speed jet tube and float needles that were binding in the seats from crusty stuff. Floats are at 14mm per spec. I understand how the bystarter operates, but on cold starts, it over primes, and I have to open the throttle to get it to start. It is definitely flooded when it finally fires up. Warm starts are instant as soon as I turn the key.
I'm thinking maybe drop the floats to 13mm. Can I get some help? I see mention of a different bystarter and bowl, but can't find any details about that and why it is different, or what it's supposed to correct.
 
DLC8113 said:
I recently purchased a 2006 BF25. (BATJ 1200600). I had to clean water out of rhe carbs and chose to replace the nasty slow speed jet tube and float needles that were binding in the seats from crusty stuff. Floats are at 14mm per spec. I understand how the bystarter operates, but on cold starts, it over primes, and I have to open the throttle to get it to start. It is definitely flooded when it finally fires up. Warm starts are instant as soon as I turn the key.
I'm thinking maybe drop the floats to 13mm. Can I get some help? I see mention of a different bystarter and bowl, but can't find any details about that and why it is different, or what it's supposed to correct.
Click to expand...
 
Hi,
I'm not sure how the bystarter could flood the carb. I've worked on quite a few and haven't seen that before.
Like you, I would suspect a high fuel level in the bowl but with no other symptoms, I'm not sure.

Only a couple of other possibilities come to mind

if someone accidentally enlarged the SE pickup with a tool while cleaning. If that occurs, the only fix is a new carburetor.

I suppose that, if the vent passage for the SE circuit was plugged, then there might be the possibility of raw fuel being siphoned through the circuit and not mixing with air. Just a guess tho.

I see there are two bystarter valves listed in the cross reference but only one,
1616130-ZW2-H01
is correct for your frame number.

It looks to be the same for the float chamber that only the original number is indicated as correct fit.

I hope that you've already figured this out.

Good luck.
 
Thanks for the input. I've not seen it before either. The bystarter works and appears to fully shutoff as it warms up. Bowl, etc all look unmolested.
It might be a day or 2 before I get back on it. I hate to pull the carbs to adjust float levels. That will be a last resort. I will probably play with cracking the throttle a little after a few revolutions when cold. I should not have to do that but it might be my best approach. I'll see how it goes when I get back to it.
 
Well, if you do end up removing the carb, make sure you hit all the vent passages (low speed, main and SE) on the Inlet mount flange with some carb spray and compressed air to ensure all three are clear.

I would definitely remove the SE valve before shooting cleaner into the vent OR the pickup tube.

Good luck with it and please keep us posted on what you find.
 
I tried 2 cold starts over a couple of days. Right now, I'm not going to try changing anything. Both times, I cracked the throttle just a hair after a couple of seconds of cranking, and it fired right up.
 
It's been a while since I worked on this. I've discovered a potential issue, but can't find what I need to make sure I get the correct parts. It looks like I have the old bystarter that begins with DR, and the float bowl has a 75 on it. The bystarter passage is clear, but I feel like there might be an orifice in it somewhere beyond the pressed in ball plug. I can blow though it, but not as much as the hole sizes I see would allow me to blow. That's why I think there is an orifice in that passage. Based on the numbers I see, it looks like there is a newer style bystarter and float bowl. How can I make sure I get the right parts if I order them?
 
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