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I'll check this out tonight. They're new clear diaphrams, but something have nicked one maybe...
Super Jet UPDATED 3/17: SuperJet Running Away/High Revs On Start... Need Help!
- Thread starter retroicon
- Start date
I'll check this out tonight. They're new clear diaphrams, but something have nicked one maybe...
- Location
- Hokesbluff,al
where are you located? maybe someone from here could help you out. still think its gonna be something simple
- Location
- Hokesbluff,al
yep, a lot of knowledge down there. goodluck with it, i know its aggrivating as hell
BruceSki
Formerly Motoman25
- Location
- Long Island
I agree with the post i thanked. that's your next step if you have been through the rest of the advice.
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If you had to put a number on it, would you say it revs up to what you'd call 1/4 throttle? Or maybe 1/2? or 3/4?
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I can't see who thanked which posts... ???
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I agree with this, priming the heck out of it, if it's truly being caused by a lean condition... but if I'm dealing with a runaway due to an airleak, how would creating a rich condition help? If it's an airleak, and not a lean condition, wouldn't priming the lines, and dumping more fuel into the carbs just cause the runaway to have more fuel... making the runaway worse?
FlightPlanDan
Don'tTrustAfartAfter50
- Location
- Crescent Beach, FL
Maybe 1/4...maybe 1/2...but I know it's gonna happen, so I'm ready to keep priming. Usually it takes a few pumps to bring it down.
After the fuel system is full it's good for the day.
If you have an air leak you might have to pump it constantly to keep the rpm's down.
I've had air leaks b4 and could not open my screws enough to compensate for the air.
If you have an air leak, it won't run right. period.
If you can prime it down and it behaves after....it's the lean condition from a "not filled" fuel system.
IMO
My limiter kicks in at 9k.
I think stock is 6k?
Just try continuing to prime while it's running. If it won't come down, maybe air leak
if it comes down, keep priming til it almost stalls. If it runs away after that, maybe air leak.
If it runs normally after bringing it down, lean condition and you have a new starting process.
BTW: a runaway or lean condition is too much air, not too much fuel.
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FlightPlanDan
Don'tTrustAfartAfter50
- Location
- Crescent Beach, FL
The one way I know to STOP a true runaway is to choke it out (kill the motor by flooding it with fuel)
- Location
- wichita, ks
x2 on that i have had it happen a couple times and the first time it scared the hell outta me.
Mark44
Katie's Boss
- Location
- 100% one place
y
Matt is correct if you have an air leak it is a lean condition. You can also instantly kill the motor by holding a rag or your shoe tightly over the exhaust outlet.
Mark44
Matt is correct if you have an air leak it is a lean condition. You can also instantly kill the motor by holding a rag or your shoe tightly over the exhaust outlet.
Mark44
- Location
- Hokesbluff,al
i just remembered my buddies ski doing the same thing a while back and it ended up being a cracked primer fuel line.
It will not make it worse. It will make it stop.
Reason: The motor will only run well at a very specific air fuel mixture. When you have a runaway condition, it is already at that point (hence it runs so well!). When you add fuel to it, you're throwing off the mixture (because you're not adding air). This kills the condition.
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A better (and faster) way is to simply hold the stop button and pull the throttle wide open.
To add to these statements, the run away engine doesn't shut off with the stop button because the spark plugs are so hot that they are maintaining the ignition without an actual spark from the electrics. In a true run away engine, you could pull the plug wires off and it'll keep going...very fast! The extra fuel cools the plugs and the engine dies. If you hit the stop button and the engine stops, it may have been really lean but it wasn't a run away engine...yet.
I will fully admit that pulling the throttle is the last thing on your mind the first couple times it happens. The engine hits max rpms in a split second and you panic. Gotta keep it in the back of your mind though.
Mark44
Katie's Boss
- Location
- 100% one place
e
I will fully admit that pulling the throttle is the last thing on your mind the first couple times it happens. The engine hits max rpms in a split second and you panic. Gotta keep it in the back of your mind though.[/QUOTE]
So true thats why I go for the exhaust.
I will fully admit that pulling the throttle is the last thing on your mind the first couple times it happens. The engine hits max rpms in a split second and you panic. Gotta keep it in the back of your mind though.[/QUOTE]
So true thats why I go for the exhaust.
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Alright, so I didn't get a chance to check it out at all yesterday, but today my wife walks in and asks me if there's any reason the garage should smell like gasoline...
Yeah, not good.
So I go into the garage, and find about 2 gallons of fuel in the bottom of the hull. The last thing I did was blow air into the check valve, and I left the petcock in the reserve position apparently... add to that I didn't have any zip ties on any of the fuel lines because I'd been taking the carbs on, and off, and on, and off ... and apparently all that pressure in the tank sent the fuel to the petcock where it leaked into the hull.
That wasn't fun, but I think I got it all out, flushed the hull with fresh water about 10 times, and everything looks good... even the paint on the engine looks alright... but it got me thinking.
Two things...
First, it seemed like the fuel lines expanded just slightly at the petcock...they slid off VERY easily. There were no zip ties on those lines, and it looked like both the reserve, and the out lines expanded slightly. So the first thought was... could the fuel lines being slightly loose cause a lean condition because they're sucking in a little air? The fuel line is helix racing fuel line... so yes, it's fuel line.
Second thought was, and this is totally random, but I have a temporary ground wire from the battery to the flywheel cover and it's attached to one of the bolts holding that on... I know this is a LONG shot, but could the ground to that spot be throwing something off ignition wise because it's grounding to the flywheel cover, instead of the starter? (I know this is not likely at all, and probably just me grasping for straws, but I'm putting it out there anyway)
Yeah, not good.
So I go into the garage, and find about 2 gallons of fuel in the bottom of the hull. The last thing I did was blow air into the check valve, and I left the petcock in the reserve position apparently... add to that I didn't have any zip ties on any of the fuel lines because I'd been taking the carbs on, and off, and on, and off ... and apparently all that pressure in the tank sent the fuel to the petcock where it leaked into the hull.
That wasn't fun, but I think I got it all out, flushed the hull with fresh water about 10 times, and everything looks good... even the paint on the engine looks alright... but it got me thinking.
Two things...
First, it seemed like the fuel lines expanded just slightly at the petcock...they slid off VERY easily. There were no zip ties on those lines, and it looked like both the reserve, and the out lines expanded slightly. So the first thought was... could the fuel lines being slightly loose cause a lean condition because they're sucking in a little air? The fuel line is helix racing fuel line... so yes, it's fuel line.
Second thought was, and this is totally random, but I have a temporary ground wire from the battery to the flywheel cover and it's attached to one of the bolts holding that on... I know this is a LONG shot, but could the ground to that spot be throwing something off ignition wise because it's grounding to the flywheel cover, instead of the starter? (I know this is not likely at all, and probably just me grasping for straws, but I'm putting it out there anyway)