she dogs, then flies! intermittent loss of power

[kenyrider]

1995 honda helix. cannot pin down this loss of power. I get on highway and it struggles to get to 62, then BLAMMO! as if a pea was stuck in the fuel line and suddenly pops out, it fixes whats wrong and suddenly lurches to 72 mph no problem!

last summer the carbuerator insulator boot was cracked and replaced it. ive also replaced the spark plug and ignition coil (seemed to help smooth accel but still doing this). im baffled. i took out the fuel filter sponge and cleaned.. not clogged. exhaust seems fine, no leaks. air filter isnt clogged.

some factors.. in the morning going to work when its still cold (im in colorado but the bike had no problems with altitude for last ten years, never changed jets) it seems to run better. BUT after work when its warm, you can almost feel compression on the engine and the MAIN telltale sign its going to do it, is that it farts and sputters and backfires when you let off the accelerator.

AGAIN, most times if you force it, aka get on the highway and just keep going while it sounds like maybe its sucking for air (thats a guess i dont really have a basis to describe that), but just keep going a mile or two, it suddenly fixes its problem and screams down the road like always (this is of course frustrating with pissed off cars behind you). this bike is all OG and only has 20k on it, most of it from me. i got it in 2008 with 9k on it and never had any problems. I do not see any leaks in any lines, cant get it to surge spraying ether around the carb..etc..

youd think if jets were clogged or something it would do it all the time! either its broke or not! ive kept up with oil changes and all religiously. getting super frustrated. Id forgotten this thing could go over 70. well yesterday when it finally broke free it hit 72 in seconds.. i think i once had it up to 78 if im remembering correctly.
when it has its problem it pretty much cant get over 62 especially in a headwind.

i dont detect any rust or water in the gas tank or lines.

ANY guesses??

Thanks in advance!

[zozman]

...last summer the carbuerator insulator boot was cracked and replaced it....

I suggest you install the 2007 Honda Helix carburetor flange support bracket and related kit as described in another post on the forum. It will stop the carburetor shake that damages intakes.

In regard to your scooter performance, or lack thereof. You obviously have a fuel delivery problem. Either its at the carburetor level or the fuel pump level. Rarely do you get sporatic issues with a faulty fuel pump.

The Honda Helix service manual describes the fuel flow test to conduct to determine if adequate fuel is being delivered by the fuel pump to the carburetor.

The run cold stall warm is indicitive of a faulty autobystarter.

By the time you completely rebuild your 1995 carburetor by adding a new autobystarter, air valve, new jets, float valve and gasket kit, and hope you rebuilt it according to specs, you might have just bought a new Honda Helix carburetor. In fact, You can buy a cheap chinese carburetor for $43. It might give you some improvement but throttle response will suffer. I recommend you NOT buy a cheap chinese clone carburetor but get the OEM Honda one. The PN 16100-KFR-842.

zoz

[kenyrider]

Hmmm.. yeah i dont think it could be the fuel pump as this has been going on the better part of a year now and it seems like it wouldve just died by now if that were the problem, not work, then not work well x 100.

The auto bystarter may be where i look next, if that needle isnt doing what its supposed to it could explain things. Oddly enough it actually seems to do this problem less after work when its been a cool summer 100 degress, but then when i stop the engine for ten minutes to pick up my kid after driving it for 20, now it will sputter or outright stall when i start it back up.

I also need to take the carb off and look for debris and make sure its all clean. ive now tried seafoam and it looked like it was helping but then nope, back to it. hard to figure out what to throw money at when the scooter isnt worth all that much but its not even to 20k yet, in spite of its age.

this is another theory here and may be in my head but it almost seems at times like i hit a big enough bump and it fixes itself. only thing i could guess there is it IS the bystarter and possibly tats dropping the needle down or up or whatever it does, but its too inconsistent to prove. ive still been riding it every single day and it hasnt killed me but id have thought any gunk in there wouldve burned off this hot summer riding it 15 miles or so each day to and from work. I hate to take it to a shop cuz theyll be all into harleys and blow all sorts of my money figuring out where to start with this thing, or at least thats what i feel.

i did clean and blow air through the filter so its not that thats clogged.

[birdmannn101]

last summer the carbuerator insulator boot was cracked and replaced it. i took out the fuel filter sponge and cleaned.. not clogged. air filter isnt clogged.

some factors. is that it farts and sputters and backfires when you let off the accelerator.

i got it in 2008 with 9k on it and never had any problems.

Sounds like rust in the tank and/or fuel filter but you say there is NO rust. That would be my first guess.

I have replaced the insulator boot with a Chinese one, only to find out that the hole where the vacuum line attaches was still plugged up with some rubber. Never had this problem with an OEM one.

I don't know what you mean by cleaning a fuel filter SPONGE. I always REPLACE the fuel filter and air filter since it doesn't take much to mess up your day with bits of debree. Farts and sputters is a good sign of air leaking at the muffler and/or insulator boot. A small crack in the insulator boot could ruin your day.

[Av8er]

Which insulator are you referring too?

[birdmannn101]

Which insulator are you referring too?

The rubber gasket between the carb and the engine.

[kenyrider]

FIXED!!!!

New auto bystarter (don’t think the pin was sealing the jet after engine warned, causing too Rich a mixture), and new muffler gasket. No backfiring.
Long struggle here!! Thanks indeed for the advice. It mattered.

[jayb79]

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.

[kenyrider]

Hmmmm. That is very interesting. My trouble with the theory though is my bike doesn’t act like it’s not pumping enough fuel, but too MUCH!
Literally when the thing is happening it chews through my gas like twice as fast!
You can even tell it’s gonna do it by the sound. When it’s happening the engine sounds like pbtththh and when it’s not doing it it’s all Roaaaawwwrrr. Literally sounds more open and not smothered. This ring a bell for you?
When mine is doing it i can feel compression on the engine. You think at first it’s a headwind but it feels almost like someone is tapping the back brake pedal and it won’t go over 62. Literally at times it will warm up and suddenly LURCH. In other words it’s like something pops free and it lurches into the way it’s supposed to run. The bike suddenly goes as fast as it’s supposed to and jumps right up to 70-72, and like i said the sound even changes. Once it’s opened up like that the rest of the ride wether it’s five more minutes or an hour it’s fast again. Then i can turn it off for ten minutes and start back up and it stalls or sputters when yiu take off and does the dogging thing all over again. Usually when it’s sucking, if you force it and ride for like a half hour it will eventually lurch and fix itself.

Does this sound familiar? Again when it’s “doing it” i can literally watch the gas gauge go down twice as fast.

[jayb79]

I don't recall it using more fuel but the symptoms sound very familiar. I would pull the plug when it dies and see if it is wet or dry. If its dry them its the pump if its wet then maybe a bad coil. I first thought my coil was bad, then worked my way through literally everything electrical including the pickup coil inside the engine. I was not smart enough to pull the plug until very late in the diagnosis. Another thing you could do is open the bowl drain when it dies and check for fuel flow.

[zozman]

... My trouble with the theory though is my bike doesn’t act like it’s not pumping enough fuel, but too MUCH! Literally when the thing is happening it chews through my gas like twice as fast!...
Again when it’s “doing it” i can literally watch the gas gauge go down twice as fast.

If the fuel pump was flooding the bowl, you'd have overflow gas on the ground.

As I mentioned in a previous post in June, eliminate your fuel delivery problem by either rebuilding the carburetor or replacing the carburetor. Most likely the jets are clogged and/or the float valve is worn. You can check to see if the float valve is bad by checking the crankcase oil for gas.

Then, if that is not the issue, you have eliminated one possible culprit and can go on to the next possible culprit.

zoz

[scootcat]

So I have been having problem with carbs on lawn mowers and chain saws and home depot suggest mechanic in a bottle, with good luck, will this work with Honda carb.

[Av8er]

NO!! Most of that crap is snake oil. Do yourself a favor and rebuild / clean the carbs.

[zozman]

So I have been having problem with carbs on lawn mowers and chain saws and home depot suggest mechanic in a bottle, with good luck, will this work with Honda carb.

NO!! Most of that crap is snake oil. Do yourself a favor and rebuild / clean the carbs.

Let's see if I can shed some light on this. For all my lawn and garden equipment as well as all my Honda scooters in storage for the winter, I use AVGAS 100LL fuel from the airport mixed with PRI-G or Stabil mixed with Sea Foam. AVGAS has a shelf life of 10 years. In 20 years, I replaced one Stihl carburetor. I have never had to replace a Honda Helix carburetor after I rebuilt it then began using this fuel. I use pump gas in my Helix during the summer, but that's OK as it is replenished regularly. Pump gas is notoriously bad after five days old. You have to keep fresh gas running through your scooter regularly and buy from a gas station that moves a lot of fuel. If you let fuel sit in the gas tank for more than a couple of weeks, you're running contaminated gas which contributes to varnish coating the inside of the carb and clogging the jets. Then you wonder with decreased performance, "what's wrong with my scooter?"


zoz

[scootcat]

thank you so much.