Bad coil?

M

mclaughlinmotorspots

Member
I have 5 gen animal and it will run good for about 5 laps on our practice track then starts to miss and act like it's running out of fuel, if you park for about 15 minutes and go out it does same thing, have went through carb multiple times, it has the blue coil, I think we have it narrowed down to the could but wanting to check here before ordering a new one in case I am missing something else
 
It "could" be the coil, but since you are using the PVL coil, I seriously doubt it. I've not seen one fail yet anyhow.
My first thought would be an inadequate vent in the fuel tank. Also check fuel filter, fuel lines, & fuel pump.

Does the engine have compression when hot? (ie head gasket or valve seat failure)


-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
28 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
I had an animal last season that did the same thing.. It would fire up on the stand, it would run fine for 3 or 4 laps and then fall flat on its face like it was running out of fuel like you described. Went thru the carb, changed the fuel pump, changed the plug and fuel line and stil did it. Replaced the coil and BAM problem solved!
 
There are many things that can cause this problem.
To determine if it is running out of fuel simply drain the carb through the drain hose into a beaker and see how much fuel comes out. It should be somewhere around 25 cc's.
If it doesn't have fuel in the bowl i would check the things that Brian said but i would also check that the vent from the valve cover is not restricted. Make sure the hose and the catch can are clear and can breath to the atmosphere freely. The catch can must be well vented.
Check the fitting in the valve cover and also the valve cover itself very thoroughly.
Also check that you don't have too hot of a spark plug in the engine. If using a Champion plug anything over a 9 heat range is too hot and will cause the engine detonate and shut off after a short time under load. You can cross reference the heat range for other spark plug brands. The engine will usually restart immediately and run for another couple of laps and shut down again.
Too much timing will do the same thing.
The kill switch wire has been know to get pinched under the air shield that wraps around the cylinder and cause sporadic engine shut downs. Remove the air shied and check the wire for signs of this. Zip tie the wire to the front coil post to prevent it from happening again.
If none of these things are the problem check the flywheel timing key. I would use a straight key or at the most a #2 key.
If all else fails replace the coil.
If someone has used a hammer to whack on the crankshaft to get the flywheel off they may have weakened the magnet and it may run very erratically. Compare the magnetism of two flywheels by how much weight they will pick up.
Always use a puller to remove the flywheel!
 
its supposed to be nice here tomorrow so I may give a few things a try, after hearing your suggestions I may be leaning towards fuel system or catch can related. the last time engine was raced it was on a different kart than it is now so there may be a problem with the tank vent or catch can on this kart, will update on what I find
 
I had same problem earlier this year and it was the coil....replaced coil and problem solved. I'd never heard of the pvl coil going bad before that
 
I forgot to explain why the valve cover, the breather tube, the hose and the catch can must be able to breathe.
It's because an Animal fuel pump is pulsed off the crankcase. If the breather system can't vent the crankcase pressure to0 the atmosphere the diaphragm in the fuel pump can't move up and down.
 
We had this problem this year and found the catch can was stopped up and not venting... pulled the vent overflow tube, problem solved.
 
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