Hard Starting in Excessive Heat


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Blue-Sun

Elite Member
I was running some errands yesterday after work, Arizona was having an excessive heat warning. I know we were supposed to hit 115 or so, but I don't know how hot is actually was.

I did notice my FZ6R was starting hard. The temperature gauge reading didn't go over 215, but I noticed after each destination; it was getting harder and harder to get re-started.

This morning in the cooler air it fired right up, as normal.

Any ideas as to what would make this happen??
 
M

ME_with_a_B

New Member
My bike would hardly start one day after work a few weeks ago. It was almost as if the battery was drained or something... after several attempts to start it (kept dying the instant it would turn over) it finally stayed running.

My garage gets really super-hot inside during the hot days. I thought maybe this had something to do with it -- but it hasn't happened since, so I have no idea what caused the problem.
 
R

ry-mac75

New Member
Not that I'm any sort of technical superstar or anything -but I do believe that extreme temperatures do effect the cell structure of batteries.
 
9

99vengeur

Administrator
Staff member
If you were doing a lot of slow stop-and-go traffic riding, when the fans kick on they will drain the battery. And since we really don't start charging the battery until the engine is above 4k rpm, it's likely that the heat and fans running was a drain on the battery.
 
B

Blue-Sun

Elite Member
99vengeur said:
If you were doing a lot of slow stop-and-go traffic riding, when the fans kick on they will drain the battery. And since we really don't start charging the battery until the engine is above 4k rpm, it's likely that the heat and fans running was a drain on the battery.
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Yes, I was on my third quick little stop. I would hope that the battery would be able to handle that type of load, but you are probably correct. As the bike was a leftover '09 at the dealer, there is no telling how long the battery sat on the shelf before being installed.

Around here most car batteries only last about 18 months. I've only had the bike for about 2.5 months and have about 850 miles on it; the thought of kicking out $$$ for a battery, so soon, leaves a bad taste in my mouth.

Thanks for everyone's input.
 
S

Superfly

New Member
Did you mean that the bike turned over many times at the normal cranking speed before it started? Thats the definition of "hard" starting. And if thats what you were experiencing you might have vapour lock in your fuel lines. Or you might have a leaky injector. You can try to crack the throttle a little and that might help as you crank it over.

If you meant that you were getting a slow crank of the engine then that would be a battery issue. Poor connections at the terminals would be a good guess if the battery is new.
 
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Blue-Sun

Elite Member
Superfly said:
Did you mean that the bike turned over many times at the normal cranking speed before it started? Thats the definition of "hard" starting. And if thats what you were experiencing you might have vapour lock in your fuel lines. Or you might have a leaky injector. You can try to crack the throttle a little and that might help as you crank it over.

If you meant that you were getting a slow crank of the engine then that would be a battery issue. Poor connections at the terminals would be a good guess if the battery is new.
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It would crank over, it just didn't want to catch. I was thinking vapor lock, but didn't think that was possible on this type of fuel injection; then I starting thinking maybe it wasn't cranking over fast enough to catch because the heat was affecting the battery??

Is vapor lock possible on this type of fuel injection?? Can you expand upon that and educate me about vapor lock??
 
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J

JonKerr

Senior Member
Elite Member
Mine has actually done this a couple of times in the heat. I just give it a little gas while on the started button and it fires right up. It's always been in situations where I've stopped and started a few times in high temps.
 
S

Superfly

New Member
Blue-Sun said:
It would crank over, it just didn't want to catch. I was thinking vapor lock, but didn't think that was possible on this type of fuel injection; then I starting thinking maybe it wasn't cranking over fast enough to catch because the heat was affecting the battery??

Is vapor lock possible on this type of fuel injection?? Can you expand upon that and educate me about vapor lock??
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OK well vapour lock occurs when you heat up the fuel lines and rails. The excess heat from the engine wells up and starts to vaporize the fuel in the injector lines and sometimes causes them to not have the fuel ready for spraying during start up. I used to have to run an aux fuel pump on a plane I used to fly to purge the lines of vapour or it wouldnt start when it was hot.

That being said you probably dont have vapour lock but might be in a flooded condition and need to allow more air into the intake (cracking the throttle slightly) as the super hot intake maybe giving you an overly rich mixture. Also if your injector(s) leaks a little after shut down your engine will be in a flooded condition if you try to start it shortly after shutdown. My corvette has been doing this for years and I just hold the throttle down to the floor as I'm hot starting and it fires right up. If I dont I have to crank over for 10 secs sometimes. When the car is cold it flashes up instantly as the fuel has dried up during the long cool off period. I hope that makes sense.

I sometimes shut the bike off but then turn the ignition on again to let the fan run for a min or two to blow some of the heat out. I dont know what good it does but its something I've been doing. The engine will be over 110C sometimes as I do this and tons of heat will pour off it. It might have a helping effect for your problem...

But regardless give your throttle a 1/4 turn or so and that might help it flash up quicker;)
 
B

Blue-Sun

Elite Member
Superfly said:
OK well vapour lock occurs when you heat up the fuel lines and rails. The excess heat from the engine wells up and starts to vaporize the fuel in the injector lines and sometimes causes them to not have the fuel ready for spraying during start up. I used to have to run an aux fuel pump on a plane I used to fly to purge the lines of vapour or it wouldnt start when it was hot.

That being said you probably dont have vapour lock but might be in a flooded condition and need to allow more air into the intake (cracking the throttle slightly) as the super hot intake maybe giving you an overly rich mixture. Also if your injector(s) leaks a little after shut down your engine will be in a flooded condition if you try to start it shortly after shutdown. My corvette has been doing this for years and I just hold the throttle down to the floor as I'm hot starting and it fires right up. If I dont I have to crank over for 10 secs sometimes. When the car is cold it flashes up instantly as the fuel has dried up during the long cool off period. I hope that makes sense.

I sometimes shut the bike off but then turn the ignition on again to let the fan run for a min or two to blow some of the heat out. I dont know what good it does but its something I've been doing. The engine will be over 110C sometimes as I do this and tons of heat will pour off it. It might have a helping effect for your problem...

But regardless give your throttle a 1/4 turn or so and that might help it flash up quicker;)
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Thanks for the explanation... It is always a good day, when you learn something new.

BTW, what type of plane did you fly?? Your avatar reminds me of a Twin Otter engine.
 

S

Superfly

New Member
Thats an engine from a dash8 which is just a sort of bigger PT6 from a Twin Otter. The PA-31-350 Navajo was the Fuel-Injected nightmare that wouldnt start Hot LOL...so embarrassing
 
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