Hi all , I have a yamoto 150 auto and although the battery is not the best I was able to use the electric start button to fire the engine .

Problem is that today when tried to start it the solenoid clatters , rather then clicks , like a demented machine gun and the engine does not turn over .
I have tried to short it across the terminals but it does nothing not even a spark ?? Is the solenoid ' Cream Crackered ' ??

Thanks for your time all

Jerry

 

It could be the battery, or it could be a bad connection. Here's what's going on:

Starters draw a lot of current. When current flows there is a drop voltage along the conductor path both to the starter and the ground return path back. The voltage drop is proportional to the current flowing. So consider the following scenario:

You have a bad battery or a bad connection that won't pass current. You turn on the ignition. So far everything is fine because nothing is drawing significant current. You press the starter button. The solenoid actuating coil (which only draws a few amps) kicks in and shorts the two big stud terminals on the solenoid which connects the battery directly to the starter motor. Now the battery and wiring are put to the test. The starter draws 35 amps or so. If you have a bad battery, or bad connection, the massive current causes a huge voltage drop. The voltage at the solenoid actuating coil drops too, and the solenoid opens. The massive load is removed, and the voltage recovers. The solenoid closes again (connecting the starter back up). The voltage collapses under the heavy starter load, the solenoid opens, and the cycle repeats. You end up with a clattering sound as the solenoid repeatedly opens and closes.

Use a pair of jumper cables to jump your quad battery to your car (take *extra* care to get the polarity right). Does the starter crank normally now? If so your battery is bad or discharged. Then we need to determine if you just have a bad battery, or if your charging system isn't working, or both.

If it doesn't crank normally we need to use a meter to figure out where the excess voltage drop is on the way to the starter motor (or the ground return back).

 

Thanks Lynn for that explanation it make great sense . I will try to jump start it ... But think the battery is a finer ..... Any idea what size battery it should have this one is 12v 3ah and is very small for the batterybox , think I read somewhere it should be 9ah .
Thanks again for the reply

 

*batteries a goner * stupid phone

 

So the battery is bad. OK. But you absolutely *must* check the charging system when you get a new one. If you don't, and your charging system is bad, you new battery will slowly discharge as you ride around. Batteries that sit discharged (even partially discharged) are damaged, and quickly ruined.

As far as which battery to buy - this is a judgement call. Let's go though the math:

A new fully charged 3 Amp-Hour (3 AH) can easily put out enough current to turn your starter motor. But for how long? A rough rule of thumb: Take the amp hour rating (3 in this case) divided by the starter motor current (roughly 35 amps) and that will give you the cranking time in hours (ball park estimate for comparison purposes).

(3 AH)/(35 A) = 0.086 hours

If you multiply that by 60 munutes per hour:

0.086 hours = 5.1 minutes.

A 9 AH battery would be 15.4 minutes of cranking time.

5 minutes of cranking time on a 3 AH battery is a lot. Out in the remote wilderness if your quad isn't going to start in 5 minutes of cranking, then likely it isn't going to start period. But if you're futzing around during this available cranking window - wiggling this connector or that , and choking the carb, checking the kill switches, etc - then maybe a little extra leeway in battery capacity could help. Maybe you might solve the problem. In that case a bigger battery will pay off. But it costs more, and if your charging system is unknown and you aren't up to fixing it quite yet, then that extra battery cost may be at risk of going to waste while it sits discharged.

Another consideration: When batteries age their output capacity goes down. A 2 year old 3 AH battery won't be anything like 3 AH after a lot of charge/discharge cycles. Eventually all batteries fail, and refuse to crank the starter motor. A 3 AH battery under ideal conditions will fail sooner than a 9 AH battery maintained under the same conditions. So do you want to pay up front for increased longevity? This is a question only you can answer...

And now the final consideration: Do you have any external loads on the 12 volt system that exceed the charging capacity of the quad charging system (about 55 watts, or about 4 amps output on my 8 pole 150cc quad at speed)? In other words does your quad ever run with an electrical load that is so great that it *must* be powered from the battery? Examples: Adding extra incandescent lights, adding winches (<=- especially this - they draw up to 80 amps under load), etc. If so, then you need a *big* battery to handle the short term load requirements. But whether you use a small battery of a big battery, you must make sure that (averaged over time) the average load isn't greater than your average charging system capacity. Otherwise your battery over time will be discharging on average, and getting slowly ruined in the process. A larger battery will get ruined a little slower, but at a higher replacement cost.

 

Thanks for the reply and info .
With jump leads on quad started almost immediately , so battery is definate goner , so will get a new one and see how things go .
Will get back to you if charging is a problem.

Just need to sort the carb now so it keeps runnin without me having to twitch the accelerator

Thanks again

jerry