1984 Honda Aero

[slolife311]

I recently purchased a 1984 Honda Aero that wasn't starting. We can get it to start with starter fluid with the throttle held open, but the fuel is obviously not getting into the engine. A friend thinks that the petcock may be the problem, but the 1984 petcock has been discontinued. He thinks it could also be the carburetor. Any suggestions on what to look for or how to fix it? Thanks!

[bfowler]

First off I have read many times on these forums to not use starter fluid in these 2 stroke engines, its not good for them. Try to open the drain screw on the carb and you should see fuel come out. Once all the fuel empties, suck on the vacuum line until the carb is full of gas. Youll know its full of gas when you see gas start to come out of the hose again. Close the drain screw and suck on the vacuum line for a little while till the carb is full of gas, about a minute. Then try to start it. Might help to put a little bit of premix down the spark plug hole as well.

[breaze]

Because 2-strokes engines receive their lubrication from the fuel (in the case of mixed gas and oil) or oil injector pumps which add oil to the fuel before going into the crankcase, you should only use mixed fuel to prime them. Starter fluid actually removes whatever lubrication is in there already and is very bad for 2-stroke engines.

Testing your petcock is easy - remove the vacuum and fuel line from the carb/intake (download service manual if you are not sure which is which - http://www.hondaspree.net/phpBB3/viewforum.php?f=11). Fuel should not flow thru the fuel line unless you apply vacuum by sucking on the vacuum line.

If you can rule out the petcock, then the carb is next. Look in Wikispreedia for directions on cleaning the carb - there are a couple of articles that will help http://hondaspree.net/wiki/index.php5?t ... al_Section. Pay special attention to the idle jet and the float valve seat ( I highly recommend the toothpaste polishing).

Remember that engines require spark, air, and fuel to run. Have you checked your airbox? Is the element in good shape, cleaned and oiled? Have you put in a new spark plug?

BTW, do you have a 50, 80, or 125?

[slolife311]

I have a 1984 Aero 50, and I definitely won't try to start it with starter fluid again. And I think the petcock is okay, we tried to clean it out and I know that fuel doesn't flow through the petcock on its own. I will check and see if it does go through when a vacuum is applied. Thanks for all the help!

[maddog]

Take the fuel line off the carb next take off the vaacuum line off the intake and suck on it if fuel flows then the jets in the carb are plugged, ethenal in the fuel does this, also the bladder inside the fuel valve will dry rot.

[slolife311]

so here is the update. after checking the petcock (which works) we took the carb apart and cleaned it, the main jet was clogged but that was about it, i used this link http://hondaspree.net/wiki/index.php5?t ... ts_-_Spree to reset the carb and these were my results: it idles ok but when i rev the engine it seems to run way to rich and kill the engine (normally i would think its running too lean and running out of fuel)... then after more cleaning it now runs better (enough to push me around al under 10 mph) but it still boggs out undr a load at higher speeds for anything more than about 5 seconds.... so then i tried putting my hand over the air intake as it was running to manually make it run more lean (this worked, and is how i came to the conclusion that it is running rich) but its not right, also the air screw seems to like to be in the all the way in position.... this is driving me nuts!!!!

[hondafan]

A couple of things, your main Jet is only one of many parts that need cleaning in a dirty carb. To do a carb job right you need to take it apart and clean everything. Gaskets should also be replaced. Once it is back together, you need to adjust the carb when the engine is running. The repair manual explains how to do it. The other thing with the 84 Aero is that it has a heat operated bystarter. These need to be hooked up properly to the carb and will act as an automatic choke. The bystarter sometimes malfunctions and will make the engine run poorly. It can cause the symptoms you are explaining. If you are getting steady fuel from your petcock And the fuel is fresh and clean and your carb is cleaned properly, the bystarter may be the culprit.

[swflcarl]

Hello brother.... take a look at your main jet needle position. I have found that scoot with blocked pilot circuit... sometimes have their needle jack up to the rich side.

These aeros too can have broken bystarters... which could leave this circuit open... causing a rich condition after start up.

1 main needle pisition
2 is pilot circuit open /clear
3 is bystarter working properly

Let us know what you find.

[breaze]

If you have the heat activated by-starter, you will not be able to adjust the carburetor unless it is functioning properly. In general you can replace the lines with clear hose and get a good feel for whether or not it is working right - when cold, you should see fuel flowing thru the fuel lines and when it warms up, nothing should be flowing.

Fortunately, it is quite easy to remove the by-starter from the equation in order to set the carb properly once the engine is warmed up. Here is a thermal choke from an Urban Express (should look similar):



Once the engine is warmed up, simply cap off the blue fuel lines (usually 1/4") at the carb and intake. The clear lines are air lines (usually 3/16") and the air is supplied by the little black air filter (actually has a small filter element inside that should be checked if you can get the thing open).

The thermal bi-metallic valve is on the right - it receives air from the element, fuel from the carb, and outputs fuel/air mix to the intake when cold. Once warmed up, the valve should close completely.

If you suspect that the choke is not functioning properly, Bear posted a mod which will turn it into a manual choke - you just need a 1/4" fuel cut-off valve and can run it like this:

[Wheelman-111]

Greetings:

That was VERY helpful, Breaze. Thank you! Mouse or Noisy, please consider Wikifying this work-around.

[slolife311]

okay, thanks guys, just reminding though that i am a complete noob with crabs that have anything electronic hooked up to them, also breaze, appreciate the time and photos, but it looks like i have a different carb, mine only has one hose coming into it, other than that is just has the float bowel drain, so i am not sure if i can do what you were recommending. after reading everybody's posts it seems like its an issue with the bystarter which i am gathering is some sort of electronic choke? if thats the case how do i isolate that? and how do i find out what the main jet position should be? also i am fairly confident that i did clean the carb well (not just the main jet, but all the little holes and other jets) thanks everybody so munch by the way!! your saving my life here!!

[breaze]

Oops, might have been helpful but not to Slolife - the 84 NB50 had the electronic choke.

[hondafan]

If you have an 84 Aero 80 you should have multiple hoses connected to the carb. It sounds like a modification was done or you have hoses missing. The 1984 Honda Aero 80 had a heat operated bystarter not an electric one. Take a picture and post it so we can see what your dealing with.

[slolife311]

It's a 1984 Aero 50. Should it still have two hoses?

[hondafan]

Sorry about that I thought I wasn't sure if it was an 80 or 50. The 50 has an electric bystarter.