Bf100 idle issues, where else to look

[48dodge]

Starting work on my new to me BF100 (1984-85ish). Initially running lean until I cleaned the carb and jets. Now, it will start and idle fine with the choke set. But once it's warm, I have to set the idle pretty high otherwise it cuts out pretty quickly. There is about 1/8th of a turn of the idle adjustment screw that will cause it to cut out. Also, I can't get it to idle low enough to where the mixture screw makes any difference. (I'm guessing that the mixture screw is for idle). Fuel lines look OK, but I'm planning on replacing them. I don't THINK it's the fuel pump since it provides enough fuel when it's idling with the choke pulled out

What I've done so far.
New fuel and tank plus flushed the lines.
Completely cleaned out the carb and jet (soaked it, maybe something has broken loose along the line so I'm planning on doing it again if I can't find anything else)
Installed new fuel filter

Any suggestions on where I should look next?

 

[48dodge]

Re: Bf100 idle issues, where else to look

OK, think it must still be running lean since I can get it to idle well by pulling the choke out slightly when warm. Also, notice air in the fuel filter when it warms up so I'm thinking there must be an air leak in the fuel line...

 

[lexi]

Re: Bf100 idle issues, where else to look

You aint mentioned the sparkplugs. Make sure they are correct type and gapped properly. The colour of them will tell you a lot about mixture settings. Did you check float settings in carb? Don`t want engine running lean as it takes more volts to spark at plugs when too lean.

Alex

 

[48dodge]

Re: Bf100 idle issues, where else to look

Sorry, meant to put that in my list. New plugs installed and gapped properly. Just picked up a clymer manual. I'll use it to check the float level. Just checking it by eye, it seems to be working properly (quite a bit of experience rebuilding car carbs and small engine carbs, first time with a Honda outboard, though)

 

[lexi]

Re: Bf100 idle issues, where else to look

Open fuel pump any and clean and check rubber diaphram? Could be a puncture in membrane pumping air into filter and/or giving low pressure.

Alex