YY250T won't start when hot By dannytroy (Read 537 times)

[dannytroy]

Well, I upgraded the R/R, went with a "better" battery, ungraded the wiring from the battery to the starter, and I'm still having problems.  The scoot starts fine when cold, but when hot it doesn't seem to have enough power in the battery to turn the engine over.  I ordered a 220CCA lithium battery and I'm hoping that solves the problem.  The voltmeter shows it at about 12.5 volts when trying to start, but after holding down the starter button a few seconds, it drops down to 8.5v under the load.  Goes back up to 12 or so volts after I let go of the starter button.

I'm thinking:
1.  The battery just doesn't have enough cranking amps to start the engine once the compression has increased, do the the hot engine, or
2.  The starter, which BTW is very hot to touch after the engine warms up, is on it's way out.

Jumping the starter solenoid doesn't help.

The voltmeter (which replaced the am-fm radio I never used) shows good charging.  I switched to a Oregon MP R/R, and the charging voltage is very good. 

Any ideas on what the problem is?

[alleyoop]

ungraded the wiring from the battery to the starter, and I'm still having problems

Wires from the battery do not go to the starter. The positive thick wire on the battery goes to 1 terminal on the SOLENOID
Then the other Terminal ON the SOLENOID goes to the Starter.

The NEGATIVE wire on the NEG POST on the battery goes to a good ground on the frame.
Alleyoop

[dannytroy]

Yes, I replaced both of those wires. The one to the solenoid and the other to the starter. The ground wire is solid, but I didn't upgrade that one. There's plenty of cranking power when the bike is cold. It's only weak when it's hot. I'm very anxious to see how well it does with the new lithium battery. From my years flying r/c planes, going from nicad, to nimh, to lithium, I know how much better lithium technology is. Hopefully it will work as well on the scoot.

[fflintstone]

(The starter, which BTW is very hot to touch after the engine warms up, is on it's way out.)(quote)
The starter will get hotter when the battery drops in voltage--low voltage means high amps,causing heat--and since the starter has been heating ,it may well be weakened--and a weakened starter will cause the battery to heat and lose its efficiency--a cruel and vicious circle--I've been there and found that trying to avoid problems usually lead to buying new battery and starter--the best way to go in the long run--btw--my Roketa instructions suggest to not engage the starter for more than 5 seconds at a time to avoid over heating--or is it 10 seconds--anyhow,you can't keep grinding away with damaging something--good luck--hope you can avoid a big bill---fflintstone


Read more: thescooterprofessor.proboards.com/thread/3838/yy250t-start-when-hot#ixzz37AbwWTQ1

[dannytroy]

Guess I'll just wait and see how it does with the new battery, which should be here in a few days. The starter isn't too expensive, so that will be next on the list of things to replace. I'm glad that otherwise it's a great running scooter.

[dannytroy]

OK, I got the new lithium battery installed and guess what...... it does the same thing. It just can't crank the engine when hot. If it would give at least one or two revolutions of the piston, I know it would start, but it doesn't have the torque to do it. The battery is at about 13 volts, and when depressing the starter button it drops down a few volts. I'm trying a new starter next. Funny, I replaced the factory battery with an AGM battery, and now with a lithium. If the replacement starter fixes the problem, I probably could have stayed with the factory battery.

[cruiser]

It sounds like you eliminated all possibilities down to the starter. I would try running an additional ground from the battery directly to the engine which would eliminate possible problems with the ground circuit between the engine and bike frame and also the battery and bike frame. BTW you sure seem to have fast shipping with your batteries. I have been curious how the lithium batteries will work in our scoots as far as longevity and reliability.

[alleyoop]

Yes, at that point its the starter does not have enough power to get past the compression stroke. One way to test it is if you have a car and jumper wires, connect the positive from the battery to the starters terminal and then holding the NEG touch the motor and see if it spins it.
Alleyoop

[dannytroy]

Jul 13, 2014 14:08:46 GMT -6 alleyoop said:

Yes, at that point its the starter does not have enough power to get past the compression stroke. Alleyoop

That is exactly what it feels like.  I was wondering if there is something that lowers the compression to allow easier starting, that isn't working.  Anyone know if these scooters have such a system?

I'll try the jumper cables with the car battery, but I'd bet it will still be the same, which will further point to a bad starter.

I ordered a new one on eBay, and it looks like they are all generic, with no "heavy duty" type available.

It makes me mad since it runs so good after it starts.  Also, it only has a few hundred miles on it, and I shouldn't have to be going through these problems so soon.

[dannytroy]

OK, problem solved. Turned out to be the starter after all. The replacement starter starts the scoot in a second or two, with no hesitation. I returned the lithium battery I bought on Amazon, so I'm only out the $50.00 for the new starter. Nice to know I can go anywhere and not worry about it starting.

[JR]

Great job!