Flooding on startup

[48Flatty]

My 52 FL floods very easy, making it difficult to start often. It was very apparent at the recent PA road run, where a couple of guys told me they always start their panheads at full throttle because of flooding at startup. I have tried that with minimal success. I have built, owned and ridden this bike for over 40 years and in the past have started it, basically, very similar to my big twin flathead. When cold, two or three prime kicks with throttle closed and full choke, then choke off, retard spark, 1/4 throttle and kick. When warm, just 1/4 throttle and kick. It has always been harder to start then my flathead and much easier to flood. However, I live at about 5000 feet, so thought maybe starting issues at the road run were somewhat related to altitude difference.
Before I left for the road run I completed a tune-up; adjusted solid lifters, set points, cleaned plugs and checked timing. When I returned I pulled the float bowl and set float level, and noted that it was a little low before I checked it. I went for a test ride yesterday. I flooded it when cold with 3 prime kicks and had to kick the crap out of it with full throttle to get it started. On the ride when warmed up, I shut it down 3 times; first time kicked it full throttle and it flooded so had to kick it a bunch with full throttle to clean it out and start it, second time tried 1/4 throttle and flooded again resulting in a bunch of kicking with full throttle to clean it out, last time tried full throttle and it fired right up. When I got home, shut it down and let it sit for 5 minutes and attempted full throttle start; once again flooded it immediately. When I checked the plugs, the front one was maybe a little light and the rear about right.
I should note that when running the bike performs very well.
Any thoughts about the tendency to flood at start up on this bike?

[T. Cotten]

...Any thoughts about the tendency to flood at start up on this bike?

One scenario among many, 48Flatty,

Is that your petcock has allowed the bowl to over-fill while sitting.

There are others...

....Cotten

[48Flatty]

I do not understand how the tank shut-off mechanism (petcock) could over-fill the float bowl, if the needle, connected to the float, seats properly in the needle seat. I checked the needle and seat when adjusting the float level, and that works properly.

[T. Cotten]

I do not understand how the tank shut-off mechanism (petcock) could over-fill the float bowl, if the needle, connected to the float, seats properly in the needle seat. I checked the needle and seat when adjusting the float level, and that works properly.

The needle is never absolute, 48!

Especially overnight. That's why there is a petcock.

I suggest dressing the petcock tip on a lathe with the toolpost set at 45°, which gives a 90° angle. With the rod still in the chuck, wrench the seat upon it firmly a few times to burnish it, and then give it the suck test.

This usually gives it another generation of service.

....Cotten

[stevewiesel]

48Flatty Are you running a Linkert M74B? I have similar issues with my 1960 FLH and live at 5,000 ft too. Did you finally figure out what the secret sauce is to get it not to flood? Mine runs amazing when I get it started. But it seems to flood at least once every time I ride it. I then tip it over to the right side and some gas drools out and then it will start right up and run like a champ. Maybe a leaky petcock?

[T. Cotten]

48Flatty Are you running a Linkert M74B? I have similar issues with my 1960 FLH and live at 5,000 ft too. Did you finally figure out what the secret sauce is to get it not to flood? Mine runs amazing when I get it started. But it seems to flood at least once every time I ride it. I then tip it over to the right side and some gas drools out and then it will start right up and run like a champ. Maybe a leaky petcock?

Its been three years, Steve!

My psychic third eye tells me your float has excessive side-play that causes it to rub and hang up upon the bowlstem, or occasionally the bowl, or possibly even both.

But I could be wrong.

The only way to make certain a float is not hanging up is to have the complete carb with indexed bowl in your hands, so you can invert it to suck upon the fuel inlet.

.....Cotten

[Iacovos]

Been there 48Flatty
This is how it worked for me (bike starting from first / second kick) M74B Carb on an FLH
Gas On
Choke Closed 3 (from 4) clicks
1/2 open throttle
2 prime kicks
Choke all the way up (open)
advance retarded and very slightly advanced
1/4 open throttle
kick to start

[48Flatty]

I believe what you are describing, lacovos, is the cold start procedure I use on my FL with an M74B. Your start procedure is basically the same as my procedure, except throttle is completely closed during prime kicks in my procedure. I had someone else tell me to open the throttle fully during prime kicks. Opening the throttle during prime kicks makes no sense to me. Isn't the purpose of the priming procedure to draw fuel into the intake manifold? With the throttle open aren't you venting some that fuel you need for the cold start? Maybe someone can explain that to me.

I am happy to report, I took the panhead to a road run in MN last September. Very cool temperatures and it started within 2 kicks every time, all 3 days. Generally speaking my flooding issues seem to happen more often with warm ambient temps (say above 80F), and while trying to start the bike when the engine is still hot or warm. One thing I have done with some success is when shutting the bike off after running it and parking it in hot temperatures, is to open the throttle fully while it sits and I enjoy an ice cold adult beverage. Thus allowing the carb to vent excess vapors caused by the heat?

I believe another issue I have is that I don't kick it with the same authority I once did. I've been starting/riding this bike for 50 years and don't remember as many starting problems when I could kick it harder. I think sometimes it would go first kick warm if I could give it more "oomph". Once the warmed up engine fails to start within a couple kicks, I think it tends to flood because I have pulled excess fuel into the manifold and combustion chambers with my half-assed kicks. It might be time for an electric starter?

[T. Cotten]

...Opening the throttle during prime kicks makes no sense to me. Isn't the purpose of the priming procedure to draw fuel into the intake manifold?

The fuel fires in the combustion chambers, you hope, 48!

Manifold fires should be avoided.

With the throttle closed, you restrict the charge of air and fuel, inducing a 'feathered choke' that would be overly rich on a tuned machine, and advantage only when cold.

With the throttle open aren't you venting some that fuel you need for the cold start? Maybe someone can explain that to me.

Venting to where, 48?

Generally speaking my flooding issues seem to happen more often with warm ambient temps (say above 80F), and while trying to start the bike when the engine is still hot or warm. One thing I have done with some success is when shutting the bike off after running it and parking it in hot temperatures, is to open the throttle fully while it sits and I enjoy an ice cold adult beverage. Thus allowing the carb to vent excess vapors caused by the heat?

If by 'flooding' you mean raw fuel, I would again refer back to post #2; If the petcock again proves absolute, the float circuit is suspect; Please inspect, as noted before, for not only buoyancy and setting issues, but for any chance of hanging up as described in #6.

If your float doesn't float, your fuel mileage probably suffers as well

JAR09.jpg

....Cotten