Sym Mio50 cold, no engine power problem with the Electric choke (Solenoid)

Andrisig

New Member
Mio50 starts but has no power when the engine is still cold. After 10 minutes the engine works fine. I think the electric choke ( Solenoid) doesn't work correctly.

How to know if the Solenoid is working as specified?
What should the length be of the solenoids needle in cold state?

The Solenoid has a needle that is shorter when cold and longer when hot. To check this I have connected the battery directly to the battery poles (12volt). The housing becomes hot (It is supposed to do so). The gained length of the needle is around three millimeters. So it seems to work, but if I measure the length in the cold state the needle already blocks the petrol flow used to make the fuel air mixture more rich. (Cold engines need more petrol in relation to the mixed air). Therefore my question: What should the length of the needle be in cold state? What will the needle length of the solenoid be after lets say 10 minutes connected to the 12 volt power supply (After 10 minutes the engine should be hot). What should the difference in length be?


I've read when measuring the resistance of the part between the positive and negative poles this sould be 10 ohms. I measure almost zero resistance... What is it suppost to be?
 
Last edited:
Advertisement - register to remove this

Hello the difference in length of the choke needle should be around 5 mm.
A most commen problem of the Sym mio is that the valves in the cilinder head are a little bit to tight. With the problem you mension is it verry often the intake valve which has to less clearance. the clearence should be 0.08 mm for the intake and 0.10 for the exhaust.
You could also check the idle yet if this is blocked he wil get less fuel aswell. and the mixture screw has to be 2,5 turns out.
The electrick choke will not brake down that fast and if its broke he will be on the choke (so a richer fuel mixture)
Good luck.
Jos Koelewijn
JRS Scooters and Myscootershop
 

Andrisig

New Member
Minimum lenght of this electric choke? Don't think the valves need to been adjusted

Hello the difference in length of the choke needle should be around 5 mm.
A most commen problem of the Sym mio is that the valves in the cilinder head are a little bit to tight. With the problem you mension is it verry often the intake valve which has to less clearance. the clearence should be 0.08 mm for the intake and 0.10 for the exhaust.
You could also check the idle yet if this is blocked he wil get less fuel aswell. and the mixture screw has to be 2,5 turns out.
The electrick choke will not brake down that fast and if its broke he will be on the choke (so a richer fuel mixture)
Good luck.
Jos Koelewijn
JRS Scooters and Myscootershop
The valve specifications according to the manual are:
Intake 0.05 +/- 0.02 Exhaust 0.10 +/- 0.02
What you suggest is to open up the intake valve to 0.08 That's a difference of +0.03 That's a lot, more then the specification maximum of (0.05+0.02=) 0.07. So I don't think that's the way to go.

The engine also runs fine on idle (stationary) Just it has no power for some minutes after a cold start. More so in winter, (takes longer to heat up). After heating up the engine the it runs fine. Changing the valves will have impact on both the cold as the warm engine. Therefor I think the trouble does not concern the valves.

Also the mixture seems to be set correct. Stationary the engine runs really sweet.

What do you mean with The electric choke will not brake down that fast? Heating up the choke will extent the needle, not shorten it. Or do you mean by breaking down? The choke must be broken (kaput)? That's what I'm trying to find out. You also mention if the choke is broke it will be on the choke? Can't understand that one, sorry :henko:

Thanks for mentioning the difference between needle length. According to you this must be 5mm between cold and warm state.

Most imported for me to know::rolleyes: What's the minimum needle length of this electric choke. Do you know?+ralf+
 
Last edited:
I don't know the minimum length.
But the electrick choke is a wash(?) element and when it heats up the needle will become longer so in cold(yust started) conditions it is always shorter. When an electrick choke is broken normaly it will not go off the choke anymore.( so it will be richer always.)
The problem wich you mension is common with a Sym mio. normaly it will help if you would yust put a little bit bigger main jet in or adjust the mixture screw and put it on 2% C.O ( i know this isn't the right solution but anyway it helps!)
In winter time below 5."c whe have to do this verry often in the shop. I think it has to do something with the length of the aloy inlet manifold. where the fuel will become drops instead of a gas mixture. anyway even the dutch importeur doesn't know what to do with this.... So yust put it a little richer Main jet about 86 instead of 80. Good luck
 
Last edited by a moderator:

Andrisig

New Member
Replacing the sprinkler using a bigger size

I will try to replace the sprinkler (main jet) Thanks for chairing your expertise, I surly don't know anything about the sprinkler sizes. I will try a 86 *D


If this is a common and well known problem {! Then the importer should do some more testing instead of walk out on the consumers and let them figure this out. :(
 
Advertisement - register to remove this
Similar threads





Top