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Did All Scooters have a Choke

Posted: Sat Apr 01, 2017 10:55 am
by DavidB
My 1983 Honda Flush (similar to an Elite) came as a basket case to me and is hard to start. It came without a choke or choke plate. It does have an enrichening device that leans it out as it warms up.

Do you users have chokes on your engines and should I make one?

Note on photograph. It shows a cage I built for wraping a foam element over as an air filter, and grass clippers for welding of a crack on the handle. But between the carburetor and filter "cage" I wondered if I should fabricate a choke device. The foam element is made by taking 1/2" thick foam, slitting it down the middle and sliding it over the frame like a sock on a foot.

I've edited this after reading some comments below. I don't think there is restriction with the handmade air cleaner. Can't sense it when breathing through it. I've seen air filters as used on chain saws and entire box assembly has the same volume as what I built. Thanks for comments though.

There is a nice flow of fuel through the fuel line. Regarding the double action oil pump that came with it, it was missing the cartridge in the pump assembly so I removed, removed the drive rod, plugged it off and mix oil directly with gas.

Re: Did All Scooters have a Choke

Posted: Sat Apr 01, 2017 11:42 am
by Meatball
Your fabricated air filter device could be the culprit for hard starts. "Open" type filters with little-to-no flow restriction result in lower vacuum pressure which would decrease fuel flow from the petcock on start-ups. Once finally running, the RPM's are increased and vacuum issues are eliminated but then the "open" filter creates a LEAN condition which is difficult (or impossible) to remedy with the non-adjustable pilot circuit of the stock carburetor. Stock filter box with a fresh filter is always optimum for stock motors.


Additional enrichment is not the remedy for whatever ailments your bike is having since the stock bystarter (when functioning properly) is all the enrichment a stock motor needs.

As far as grass clippers go... :crazy:

Re: Did All Scooters have a Choke

Posted: Sat Apr 01, 2017 12:12 pm
by motormike
Throw the chicken-wire away and adapt an actual 50cc scooter airbox to fit and your trouble starting will be gone.
Replace those fuel lines, or expect mysterious debris plugging every orifice in the carburetor.

Re: Did All Scooters have a Choke

Posted: Sat Apr 01, 2017 5:22 pm
by noiseguy
That black plastic thing in the back is the "enrichment circuit" for cold start. There is no choke per se.

Agree with all other comments. Get a real airbox.

Re: Did All Scooters have a Choke

Posted: Sun Apr 02, 2017 11:36 am
by benji
Agreed. You need an oem air box and you'll be golden. What motor code is it? Af05? Af16?

Re: Did All Scooters have a Choke

Posted: Sun Oct 08, 2017 7:34 pm
by DavidB
If you mean first 4 digits of the serial number which helped identify it as a Honda Flush, it is AB19.

Re: Did All Scooters have a Choke

Posted: Sun Oct 08, 2017 11:12 pm
by motormike
DavidB wrote: I don't think there is restriction with the handmade air cleaner. Can't sense it when breathing through it.
Maybe you have misunderstood....the air filter on these small scooters
is designed to have RESTRICTION so that the engine vacuum will PULL GAS from the bowl at SPECIFIC RATE.
When your REMOVE ANY of the RESTRICTION by altering or eliminating the air filter, you have CHANGED the engines ability to PULL GAS from the bowl, so now, you are pulling WAY TOO MUCH AIR> Hope this is clear NOW... :urban:

Re: Did All Scooters have a Choke

Posted: Mon Oct 09, 2017 2:57 am
by eclark5483
For an FYI, when you pull back the throttle, you are not letting in more fuel, you are letting in more air. The filter system plays a huge role in how the mixture reacts with vacuum in the venturi. A common misconception is that letting in more air at the filter side will improve performance, when actually, what you are doing, is affecting vacuum pressure.

Re: Did All Scooters have a Choke

Posted: Mon Oct 09, 2017 11:05 pm
by motormike
"Did All Scooters Have A Choke?"- was your question. ( I added the punctuation ;) )

To answer, virtually NO scooter EVER had a choke plate or butterfly.
The enrichment circuit, bystarter, combined with the meticulous design
of the air filtration system eliminated the use of choke plates... :urban:

Re: Did All Scooters have a Choke

Posted: Sun Aug 30, 2020 11:27 pm
by DavidB
What clark5483 said about not opening the throttle during cranking I've proved to be true. Keep it closed so the "automatic bystarter" can enrichen the air/fuel mixture. Just takes a few seconds for it to start up. My Honda Flush has a dropping resistor in series with the automatic bystarter. The AC voltage that varies with RPM to the automatic bystarter is 5 VAC and to the resistor, 5 VAC. Theoretically the bystarter shuts off the enrichment after 2 minutes of run time.

Thanks for the comments that scooters didn't have chokes. I have minimal experience with 2 cycle engines, much less, scooters. The weed eater and chain saw I have do have chokes.