Hello I have a hammerhead 250cc go kart. And last time I used it after about 30 minutes of driving at 75 degrees outside in the evening only about 3 of those minutes where at high rpms. I heard some popping stuff high rpms so I stopped and it backfired loud so I drove 100 feet to my shop and it did it 2 more times. So I let it rest I think it might have overheated but unsure the cooling fans where on the whole time (I have them on a toggle switch). The ride after that it didn't seem like it was reving as high as it did before and it still had some minor popping so I put it away and that is where it has sat for about 2 1/2 weeks. It always starts right up. I am wondering what is wrong could it Be my top end or something different. Because I was told before on this form that high rpms shouldn't hurt my engine. And why should it over heat when I have the fans on full blast all the time and the coolant looks nice and green not brown or corroded. Oh and by the ways it has a little over two thousand hours on it ps.i am pretty sure it overheated. Thanks for any help.
Hammerhead overheating and backfireing
- Thread starter Isaac123
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Well first check your spark plug
if it's computer-white (beige) you are running too lean and need to adjust your carb, that alone can cause serious overheating after just a short period of time..
and with overheating I'm talking spark plug, not engine yet
if it's tan you should be good with the carb setting and could move on looking for other issues..
Now the hammerhead has an e-start, right?
recharge your battery, let it sit for 24h, then measure the voltage;
if it's less than 12.8V replace the battery with a fresh one.
Yes, that does sound stupid to the max, I myself cannot wrap my head around it tbh..
but my sis's motorbike was haveing some nasty backfiring when she asked me to check on it.
and the ONLY thing wrong with it I could find was a bad battery...
recharged, drove->backfire...
cleaned carb, spark plugs, tank, fuel filter, terminals of the ignition coils ... drove->backfired still
installed a new battery and it purred like a kitten...
AMAZED.. reinstalled old battery to double check.. drove and she backfired on me again (running WAAAY too hot)
No, it doesn't make any sense to me I must admit, the only thing I could think of is the alternator having to do some serious heavy lifting (maybe a shortened out cell in the battery or something) and thus heat up itself... but frankly IDK...
So if no fuel/mix/sparkplug issue is detectable.. it might be worth to check the battery in case you suffer from the same absurdness
'sid
if it's computer-white (beige) you are running too lean and need to adjust your carb, that alone can cause serious overheating after just a short period of time..
and with overheating I'm talking spark plug, not engine yet
if it's tan you should be good with the carb setting and could move on looking for other issues..
Now the hammerhead has an e-start, right?
recharge your battery, let it sit for 24h, then measure the voltage;
if it's less than 12.8V replace the battery with a fresh one.
Yes, that does sound stupid to the max, I myself cannot wrap my head around it tbh..
but my sis's motorbike was haveing some nasty backfiring when she asked me to check on it.
and the ONLY thing wrong with it I could find was a bad battery...
recharged, drove->backfire...
cleaned carb, spark plugs, tank, fuel filter, terminals of the ignition coils ... drove->backfired still
installed a new battery and it purred like a kitten...
AMAZED.. reinstalled old battery to double check.. drove and she backfired on me again (running WAAAY too hot)
No, it doesn't make any sense to me I must admit, the only thing I could think of is the alternator having to do some serious heavy lifting (maybe a shortened out cell in the battery or something) and thus heat up itself... but frankly IDK...
So if no fuel/mix/sparkplug issue is detectable.. it might be worth to check the battery in case you suffer from the same absurdness
'sid
Karttekk
Well-known member
Sounds like an ignition issue to me. It very well could be the battery. I think what's going on is an ignition system component or the battery is failing. The backfiring is caused by unburned fuel from the combustion chamber is hitting the hot exhaust and igniting there. Have the battery tested and if it proves good start looking at a magneto or coil going away when the engine heats up and not providing enough spark to completely burn the mixture in the combustion chamber on the power stroke.
"When an engine runs too rich, there is too much fuel to create an explosive, fast-burning flame. When that happens, the fuel burns slower, and isn’t complete before the exhaust part of the engine cycle. When the exhaust valve opens on that cylinder, the extra air allows the unburned fuel to explosively burn and the popping noise of a backfire is heard." (Taken from a "Your Mechanic" article.)
"When an engine runs too rich, there is too much fuel to create an explosive, fast-burning flame. When that happens, the fuel burns slower, and isn’t complete before the exhaust part of the engine cycle. When the exhaust valve opens on that cylinder, the extra air allows the unburned fuel to explosively burn and the popping noise of a backfire is heard." (Taken from a "Your Mechanic" article.)
Whitetrashrocker
Inmate #952016
I'll back up the strange battery story.
Had a friend with a quad that he couldn't get started and run. Charge battery and it would start and run for a minute if you held the starter button. Let go of the button and it would die.
He out a new battery and it all went away.
Had a friend with a quad that he couldn't get started and run. Charge battery and it would start and run for a minute if you held the starter button. Let go of the button and it would die.
He out a new battery and it all went away.
Sure enough unburnt fuel ignites at the hot exhaust..
but that can be because of two reasons:
1) rich fuel and thus a high ratio of unburnt fuel on a just below ordinary hot exhaust..
2) fuel residue on a lean engine
choke pumps a ignitionworthy amount of fuel into the exhaust while it itself is still cool'ish
lean mix heats up the exhaust past the ignition point and the residue pops off
(one single gunshot like on carb cleaner started engines at times..)
Sure enough.. constant backfiring is more likely rich fuelmix than lean one..
but since applied choke richens up the fuel anyways... it could be just residue
[having the choke on for too long or such]
but frankly.. since you should clean or at least check the spark plug anyways in case of backfiring,
it's a no brainer to judge fuel mix by the spark plug color to be sure to turn the knob in the right direction, not?
'sid
but that can be because of two reasons:
1) rich fuel and thus a high ratio of unburnt fuel on a just below ordinary hot exhaust..
2) fuel residue on a lean engine
choke pumps a ignitionworthy amount of fuel into the exhaust while it itself is still cool'ish
lean mix heats up the exhaust past the ignition point and the residue pops off
(one single gunshot like on carb cleaner started engines at times..)
Sure enough.. constant backfiring is more likely rich fuelmix than lean one..
but since applied choke richens up the fuel anyways... it could be just residue
[having the choke on for too long or such]
but frankly.. since you should clean or at least check the spark plug anyways in case of backfiring,
it's a no brainer to judge fuel mix by the spark plug color to be sure to turn the knob in the right direction, not?
'sid
Karttekk
Well-known member
I mentioned ignition components because they usually act up or show symptoms like that when hot. The battery may hold just enough charge to keep the kart running until it runs out of juice and it may do that as the motor heats up. Guess cheap, a battery is the cheapest and easiest place to start as is a spark plug.
65ShelbyClone
Active member
There are a lot of possibilities, even more with no troubleshooting results.
Before spending money, do simple things like check the spark, compression, battery voltage, and pull the float bowl to see if there's debris in the carburetor. It could be as simple as a partially blocked jet or your always-on fans draining the battery. We don't know yet.
What engine does it have? I found something about a Honda CH250 copy, but didn't look any further. Really that's information that should be provided up front.
Are you sure it's two thousand hours? The engine would probably be well worn out at 2000 hours.
So it boiled over?
Before spending money, do simple things like check the spark, compression, battery voltage, and pull the float bowl to see if there's debris in the carburetor. It could be as simple as a partially blocked jet or your always-on fans draining the battery. We don't know yet.
What engine does it have? I found something about a Honda CH250 copy, but didn't look any further. Really that's information that should be provided up front.
Are you sure it's two thousand hours? The engine would probably be well worn out at 2000 hours.
So it boiled over?
No it did not boil over but the symptoms I had were that of an overheated engine. And according to the screen it has two thousand miles on it. So if the engine was worn out how would I be able to tell without a compression tester because I don't like spending money on tools I will only use one or twice.
---------- Post added at 02:53 PM ---------- Previous post was at 02:52 PM ----------
Oh and it has a CF MOTO 250cc engine if you want too see it they have it on hammerheads website.
---------- Post added at 02:53 PM ---------- Previous post was at 02:52 PM ----------
Oh and it has a CF MOTO 250cc engine if you want too see it they have it on hammerheads website.
Karttekk
Well-known member
Coil? Does it have a CDI? Run it with an inline spark tester in the plug wire, see if you're losing spark when it heats up. Radiator cap? Pressure test the cooling system. Back flush the cooling system. Any way to rig up an actual temp gauge and watch it?
Karttekk
Well-known member
You would have to remove the pump and check if the impeller blades are worn or of the impeller is slipping on the shaft. Not sure of any other way. With automobiles you can watch for coolant flow with the rad cap off once the thermostat opens, not sure how a kart system works.
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