Engine wont start? TROUBLESHOOTING GUIDE



Toby

New Member
Joined
Mar 1, 2020
Messages
3
If your Happy Time engine isnt starting then work your way through this guide to identify and fix the problem. Still no hope? then just ask...
With many thanks to BoltsMissing who compiled this great troubleshooting guide. Thanks to Lordoflightaz too for a few tips :)


Firstly start off by checking that the fuel petcock is on and you have fuel. Check the wires to the CDI. Make sure that they are connected. The cheap connectors come loose

1. Remove spark plug, check gap.
2. Check for spark with lead on plug and earth spark plug on cylinder head fin.

Lift the rear wheel, and give it one good hard pedal down as if you are
kick-starting a bike. If plug sparks at the tip, re-install the spark plug. (just bear in mind that I have had plugs that fire under no compression(Not in engine)but had no spark under compression(In engine)This can be a pain if you Don't know this.You could pull your hair out with this problem,new plugs are cheap!)

2a. If no spark, check Plug cap. I had to replace mine with a NGK Right Angle spark plug cap, (don't know the part No. though)
2b. Repalce lead anyway with Copper wire lead.
Check for spark again with new lead and plug cap
That's the electrical done from start of lead to end of plug tip.

If Spark, then go to Fuel.
If No Spark, go to Magneto and CDI.
But don't just replace the Magneto and CDI unless you do all the obove to.
That way you have a clean sweep out of sight out of kind type of thing of the electrics.

Fuel.
Remove Carby, AFTER Spark is all clear as explained above.
Remove fuel bowl, see if it was full or any fuel was in there.
If not, check fuel line and needle/seat where the fuel line plugs in.
There may be some grit.
If it had fuel in fuel bowl, re-fit carby.

Fuel is OK up to fuel bowl end.

Clutch adjustment, just go through the motions at the cable end. There should be no slack.
Can't say much about whats behind the clutch cover, never had one with problems ,yet.

By this time you probably flooded it trying to start and doing the other testings.

Then as last resort as I mentioned earlier,
Tow start,
and this will "flush out" the remaining cob-webs, and it ought to go.
Tow around the block or whatever until all reasonable doubt is undoubted if it still don't start. Be very careful though as this could be dangerous!

Failing a tow start, then start the inspection process again the next day, so take a break, it's only a Happy Time (HT) engine.
This time check for Head/Lower cylinder/Exhaust and Carby Gasket leaks etc.
Point is, dwelve deeper into the problem.
Tow again if all looks OK.

Remember if an engine has compression, fuel (air and petrol) and a spark then it must fire, it doesnt have a choice! ;)
 

Toby

New Member
Joined
Mar 1, 2020
Messages
3
Hey guys, I am having trouble starting my bike for the first time ( this is my first build). I have checked that my wiring is correct from my CDI
and that my fuel line is fine, I have turned on fuel and pumped gas into the carb. When I try to start the bike it just makes a sound as if the engine is tuning over a few times but the bike never starts. Anyone have any tips? Thank you!
 

Chainlube

Well-Known Member
Joined
Jan 5, 2020
Messages
1,387
Did you do a spark check? Pull the spark plug out and put the wire back on and rest the plug on top of the engine, might have to tape it there, and roll the bike forward and watch the end of the plug. Do see a spark?
 

Chainlube

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Joined
Jan 5, 2020
Messages
1,387
These little engines don't start instantly, you have to work it a little bit. Put the choke on, choke arm up, get to know where it is, so you can turn it off when it starts.
 

hazmat

Member
Joined
Aug 26, 2016
Messages
87
lol my engine wont start now so i took magneto and magnet off and sanded down the block for better contact took off head and took a peak had some smoke in there so im guessing my plug is bad or i spilled oil in the crankcase where there is so much in there the volume is off gonna find out later today when i put my son in the pool
 

Don_Parsons

Active Member
Joined
May 6, 2020
Messages
649
Yes,,, some times the 2-Somke oil becomes to much for the plug,,, that might be why they recommend that you carrying or have a few extra plugs in the outting kit,,, sometimes those little oily plugs give up the ghost just like that..

Proper air/ fuel mix at the right moment in time under some kinda of compression with a spark that is timed makes it happen...

All good when its all in sync...
 

FurryOnTheInside

Well-Known Member
Joined
Sep 23, 2013
Messages
3,923
Carry a few spare cheap plugs, or the spend the same amount on one very reliable plug and carry less spare stuff.
I use an iridium plug. It is meant to avoid surface corrosion where the spark hits it, and thereby keep its shiny smooth surface texture, so that less oil/carbon can adhere to it to block that spark. Any burnt oil washes off the ever shiny iridium surface when the transfers open and the fresh charge comes in.
(Hopefully. I probably jinxed it now.)
 

inspectorcritic

Well-Known Member
Joined
Dec 13, 2015
Messages
1,377
lol my engine wont start now so i took magneto and magnet off and sanded down the block for better contact took off head and took a peak had some smoke in there so im guessing my plug is bad or i spilled oil in the crankcase where there is so much in there the volume is off gonna find out later today when i put my son in the pool
Try this is sometimes the caused found out myself.
Has your clutch cable slip?
Push your bike if it's hard to turn the wheel then suck up the cable, clutch has got to be totally free in order friction drop.
Another thing I found out E3 plugs give better starting, power not too noticeble they claim something 17% increase.
Guess you have heard it before take the plug out , stick back in the boot, ground it turn rear wheel look for spark if not next suspect CDI
 
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