85 Aero, Consistent starting problem. Need some help!

[Buzzingbee89]

Hello everybody,
I've got a 85 Aero 50 that i've had a problem with for a while. After sitting overnight, it won't start. I have gas and spark. I've rebuilt the carb twice. A friend of mine swears its the petcock, but don't think it is. Any ideas? Thanks.

Ryan

[wikked_spree57]

probably need a new bystarter. that's the cold start enrichment system so it will start easy when cold. sounds like it's stuck shut. pull it out and see if it is in the extended position when cold. If so, there's your problem.

hope this helps!

Lack of a filter in the air box causes this sometimes also.

[Buzzingbee89]

Thanks for the feedback. Now I have a place to start.

[Wheelman-111]

Greetings:

When I disassembled Flash I's carb the first time, the brass plunger from the Bystarter broke off the assembly and was firmly cemented in its bore. You'd think it would get stuck in the "Default" cold-start retracted position, though. If yours runs fine once you get it started, the bystarter may not be your issue.

A leaky float needle and overflow down into the intake might be another explanation. Flooded with gas, it'll take a while to fire. Confirm by smelling raw gasoline when you remove the spark plug after cranking a few turns. Wet muffler outlet would be further evidence that this is happening.

On the other hand, if the float needle is sticking closed, it'll sputter initially but not quite start. However I couldn't easily explain how this self-corrects with starting fluid or protracted cranking, unless the fuel flow eventually works it loose. Not a good fit to your symptoms.

After a really long rest between starts, one other issue that arises is that the fuel in the bowl evaporates down to sub-running levels. The engine has to pull vacuum to the petcock for a long time before the carb refills. However this takes several days, usually.

Two carb cleanings is sub-par for most Aero-newbies. Ensure the emulsion tube, the bystarter mini-jet, and the Legendary Pin-* O' Light have been established as clear.

[maddog]

the bladder in the petcock will dry rot, an easy way to test it is to suck on the vacuum line, if it sticks to your tongue then it still works!

[Buzzingbee89]

I've continued to mess with it the past couple of days. Here's what I found.
The jet needle was on the wrong groove, or so I thought. It tells you what groove it should be in the manual, but, it doesn't say if it's four grooves from the top or the bottom.

I put the vacuum tube from the petcock and sucked on it and gas went into the line. Not sure if that means its good or not.

Now when I get it to run. around 15 mph it sputters and then dies, like its not getting gas, but there's plenty in the line. The carb has a fairly new float and needle too.

New thing I found that might get you guys going is this. Some one took the exhaust and gutted it. Not sure if this may be my problem or not.

Thanks again for the feedback!

[Wheelman-111]

Greetings:

The muffler probably isn't causing this issue. I'd carefully examine the float needle assembly and be sure the little inlet hole is clear of sludge. Perhaps install a Cone O' Stone inline filter. Check the tank petcock screen for gunk too.

[Buzzingbee89]

I took the carb apart and sure enough the jet needle inlet and the petcock were clogged really bad. I put the strainer back in the gas tank and cleaned the carb and petcock. It runs good now, my battery is deader then M J though.

If I put a cone filter on it, would I have to rejet the carb and what not?

[maddog]

stay away from a pod filter, the metal fan shroud makes this engine run hot, go to a #8 or 9 ngk plug.

[Buzzingbee89]

Now here's where I get confused. I run snowmobiles in the winter time. And everytime I put a hotter sparkplug in it, i burn a hole in the piston. Would I run into the same problem if I put a #8 or #9 NGK on my little 50cc?

[Bear45-70]

To answer your questions in order;

When adding a fuel line filter you do NOT have to re-jet.

No, you will not burn a hole in your piston by running a hotter plug. Honda gives these hotter plug

The reason you are burning a hole in your snowmobile piston with the hotter plug is that you are way to close to TOO lean with your regular plug. Go up one size minimum on your main jet and run the hotter plug. You might try raising your needle too.

[Buzzingbee89]

Ok just checking. Here's another question that you all may have heard. For the jet needle, it says to place the clip on the fourth groove on it. Is it four grooves from the TOP or the BOTTOM?

[Wheelman-111]

Greetings:

Dunno where you read that, but all the Stock Honda carbs I've examined had only 3 grooves. You may know this already, so forgive me if so:

The clip grooves determine how far in or out the needle penetrates the main jet at a given throttle setting. Setting the clip to the lowest (closest to the pointy tip...) raises the needle and richens the mixture. Putting the clip closer to the uppermost groove (away from the tip...) lowers the needle and leans the part-throttle mixture.

I'd suggest you check your spark plug when the symptoms occur. If it's excessively wet and oily, suggesting it's bogging on a rich mixture condition, perhaps lowering the needle - putting the clip higher away from the tip - will help. If the insulator is pale and dry, richen the needle.

All this presumes the carb, including the many "Gotcha" passageways and the emulsion tube under the Main Jet, are clean.