Ask The Experts

[zozman]

Hi Group!

Recently, a friend who has a 1997 Honda Helix asked me to help him with start ability issues with his scoot.

Issue:

The scooter starts, runs for 15-20 seconds then stalls. Its like someone turns off the scooter when it’s running.

Tried:

I rebuilt the carburetor. Gas fills the bowl and I’m able to drain gas from the carburetor bowl.

I changed the autobystarter to a new OEM Honda one.

There are no vacuum issues.

A new air filter was installed.

I replaced the fuel filter.

Strong battery cranks the scoot well.

The fuel pump is supplying ample amount of gas to the carburetor and passed the service manual test

100-octane gas is being used. Either will not keep scooter running after 15-20 seconds.

The spark plug is supplying a hot spark on test to the cylinder. The cranking test confirms this.

The CDI was the only part I was unable to change out.

What has others exhibited with similar issues? Give me some ideas here.

zoz

[charlie55]

Sure doesn't sound like a fuel issue - even a vapor-locked tank would give you more run time than that.

Curious - did you run the spark test for 15-20 seconds or more? I know that might be a little rough on the starter, but there might be an electrical fault (CDI/coil/ignition pulse generator) that only occurs after that much time has elapsed, so you'll get 15-20 seconds of spark before it goes pffft. Just spitballing, but I'm thinking maybe a bad capacitor in the CDI that's losing its ability to hold a charge after "x" number of charge/discharge cycles.

Also, are you able to restart it immediately, or do you have to wait?

[zozman]

Hi Charlie.

I ran the spark test for ten seconds. Plug is good. Spark is good.

Once the scoot shuts itself off. If I wait 30 seconds or so, it will restart then fails again.

I'm leaning toward the CDI or pulse generator.

I'm going to see if I can get a used CDI then armed with that I'll also do a pulse generator test with my meter while there. I don't have the scooter at my home. I have to drive nine miles to the scooter.

zoz

[Dan_Lockwood]

I would imagine that you have the air breather off to the carb, but if not, take it off.

When the motor starts to die, place a rag or the palm of you hand over the carb throat and see if it picks up again for a few more seconds. This will tell you fuel or spark really quick.

Or even a shot of WD-40 in the throat will bring about a few more seconds of run time if it's a fuel issue.

Good luck and let us know what you find out.

[dano60]

Definitely sounds like an electrical issue.

Check all wiring and connections, and all switches and or sensors that could kill the engine like
the kick stand , handlebar switch, and ignition. Something might be loose or insulation worn off to
cause it to short. I had a honda lawn mower do the same thing and took into the mower shop, and turned out to be the spark plug.

Good luck Zoz, and I'm sure you'll figure it out.

Dan

[scootcat]

I had similar problem, I gave up and bought eBay carb and problem solved. But I must say by starter does not work well.

[zozman]

On the original post follow-up:

I checked all the fuses and they are good.

I replaced the ICM/CDI "brain box" and the issue remains.

If the owner of the scooter wants to remove the plastic to have me check the pulse geenerator, that would be the next option.

Doesn't look like it. I see no further action in this matter.

zoz

[Dan_Lockwood]

Still sounds like a fuel delivery issue of some sort. But I've been wrong before...

[zozman]

Still sounds like a fuel delivery issue of some sort. But I've been wrong before...

I think it is your fuel pump, these pumps are plunger style pumps and it will stick intermittently causing it to stop pumping. I was fighting this same problem for a couple of years before I gave in and tried a different pump(after changing lots of other parts first) no more problems. I think the ethanol fuel causes the piston in the pump to get a rust spot on it making it stick. Since I changed my pump I always add about 1-2 ozs of 2 stroke oil when filling and have not had any trouble.

I believe the assessments by the above "experts" are correct. Although the fuel pump appeared to be pumping when tested, it may have then failed under pressure causing the scooter to stop running. The owner will know when and if he takes it in to the dealer. The fuel pumps are $147.


zoz

[Charles]

My towers that hold the carb float had wore to a larger size than the floats pin and caused problems.

[zozman]

The original OP reported to me that the issue was resolved. He had taken it to a scooter repair shop. It took several tries but the issue was found.

The O-ring was missing from the intake. The intake was replaced along with a new spark plug.

Runs well now.


zoz

[birdmannn101]

Wow! Who would have guessed that was the problem. Thanks for getting back to us on this Randy.

[zozman]

Wow! Who would have guessed that was the problem. Thanks for getting back to us on this Randy.

After looking at the parts fiche for the intake, the o-ring sits BETWEEN the intake and the head! I checked everything. I would not normally have removed the intake to see if the o-ring was there. Kudos to the wrench who found it!

I surmise that the prevoious owner had done carburetor work to the scooter since I noticed the limiter cap missing from his carburetor and maybe had removed the intake and lost the o-ring.

What is important here is that when posters have a problem and they report it here, we document what was tried to find the remedy and what didn't work in resolving the issue then post what resolved the issue as a database resource.


zoz