1986 Honda Aero 50 starts but dies after 5 sec

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josherl
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1986 Honda Aero 50 starts but dies after 5 sec

Post by josherl »

Hello all, I have inherited a 1986 Honda Aero 50 that was sitting for a long time and would not even turn over when I got it. Since than, I have been able to start by spaying starting fluid in the intake but it will only run for a few seconds. A little history on the issues. Oil was leaking into the crank causing the piston to not move when cranked and that has been cleaned out. Now it tries to start but won't so i changed the spark plug, carb, battery, fuel lines, and I cleaned out the fuel tank. Checked piston compression, good there. Checked petcock to see if operational, good there. I read a thread that said the exhaust could be the problem so I took that off and same issue. Another thread said, these won't stay running unless if the air filter and box were on so I put that back on with a new filter and same issue. I am stuck and don't know where to look. It's almost like something is telling the motor to turn off. Any ideas? Thanks in advance!
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vintagegarage
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Re: 1986 Honda Aero 50 starts but dies after 5 sec

Post by vintagegarage »

Stop using starter fluid and use a squirt can with a gasoline and a small amount of oil in it. Before you try to start it again, open the drain screw at the bottom of the carb and see how much gasoline runs out. If the carb float bowl is empty, it should obviously be full. If it was full before you opened the drain screw, there was enough gasoline in the carb to run for perhaps 20 seconds or more. Instead of removing the air box to spray gasoline into the intake, leave the airbox in place, unscrew the cap (what the throttle cable runs through) at the top of the carb, lift the cap slightly without removing the slide, and squirt your gas/oil mix directly in the slide chamber. Then screw the cap back on. Hit the starter, and the engine should start and run very well for a few seconds. If it does, and then stops, your carb either has no fuel in the float bowl, or the main jet or idle jet is plugged. Please report back what you find, and also take a minute to update your profile with the name of the state you live in.
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Wheelman-111
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Re: 1986 Honda Aero 50 starts but dies after 5 sec

Post by Wheelman-111 »

Greetings:

If it sat long enough to fill the crankcase, I believe I spreak pretty much for all the Denizens of this Esteemed Forum when I say REMOVE that random Asian clone and CLEAN THE STOCK CARB.
You did a lot of work with that long list of things, and removing and dismantling the Honda stock carb might seem to be a daunting task for the first time. However these little PA beasts are about as simple as they get. The tricky part is getting that Idle circuit cleaned out. Another issue you may encounter is breaking off the bystarter plunger attempting to remove it. Patience a can or 2 of carb cleaner, some stainless wire bristles and a gallon of Berryman's will almost certainly prevail as it is obvious that your engine has compression and spark. See Wiki for dozens of step-by steps or find some on YouTube. Good luck!
Wheelman-111
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"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
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josherl
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Re: 1986 Honda Aero 50 starts but dies after 5 sec

Post by josherl »

@vintagegarage @wheelman-111 the scooter has an automatic oil regulator that feeds two stroke oil directly into the carb that mixes with the fuel. No need to premix here. Stock carb is gone so I have no option to go back. Took off carb to do some tests and checked the main jet for debris (even though it's new) and it was clear. Put jet back on with throttle needle in place and discovered that carb cleaner would not pass through because the needle was too far in. Started tinkering with throttle screw to open up the needle and took off the air box to use my hand as a manual choke. I was able to start her up and keep her running but only if I left the throttle wide open. Next, I opened the idle screw by all the way and now it stays running without opening the throttle all the way. She still has an issue with cold starting but I took her for a first ride this weekend with no problems.
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