The engine that keeps going
08-10-2004 | 09:51 PM
#1
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The engine that keeps going
What could cause an engine not to shut off?? When I close the throttle, the carb is closed just by looking at it, but the engine still wants to run.. Only way I can get it to shut off is by putting my finger on the carb.
Any ideas?
Any ideas?
08-10-2004 | 09:56 PM
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From: Fort Mohave,
AZ
RE: The engine that keeps going
You may be sucking air around the carb.. I believe you can adjust the
amount the barrel of the carb closes that may help.. As long as the carb
is on tight and not leaking/sucking air elsewhere...
amount the barrel of the carb closes that may help.. As long as the carb
is on tight and not leaking/sucking air elsewhere...
08-10-2004 | 10:02 PM
#5
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RE: The engine that keeps going
ORIGINAL: Aeronaut
AIR LEAK!
Jim
AIR LEAK!
Jim
08-10-2004 | 10:19 PM
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From: South West Rocks N.S.W., AUSTRALIA
RE: The engine that keeps going
Hi,
As the others have said it has to be an air leak on the inlet side. Check the needle valve assembly by placing a piece of fuel tubing around the shaft of the needle vave, (you have to remove the needle then slide on the fuel tubing over the spray bar then reinsert the needle and reset). It could also be sucking air around the carby body where it fits into the housing with a possibly damaged O ring or through the screws that locate the carby. It could even be a missing screw from the back plate or an ill fitting back plate. Try changing one thing at a time and use the process of elimination.
Good Luck,
Colin
As the others have said it has to be an air leak on the inlet side. Check the needle valve assembly by placing a piece of fuel tubing around the shaft of the needle vave, (you have to remove the needle then slide on the fuel tubing over the spray bar then reinsert the needle and reset). It could also be sucking air around the carby body where it fits into the housing with a possibly damaged O ring or through the screws that locate the carby. It could even be a missing screw from the back plate or an ill fitting back plate. Try changing one thing at a time and use the process of elimination.
Good Luck,
Colin
08-10-2004 | 10:22 PM
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From: Spring Hill,
FL
RE: The engine that keeps going
Sounds like an air leak to me too. You said you can see the carb is all the way closed so this probably isn't the problem but check that the throttle stop screw doesn't stop the barrel from closing far enough to shut off the engine.
That's the little screw behind the carb that's normally on the right side as looking at the engine from the cockpit. It also holds the carburetor barrel in so it doesn't fall out.
That's the little screw behind the carb that's normally on the right side as looking at the engine from the cockpit. It also holds the carburetor barrel in so it doesn't fall out.
08-11-2004 | 08:17 AM
#9
RE: The engine that keeps going
What engine is it?? There are some brands that known to have this problem such as the GMS and Tower Hobbies engines. I have a Tiger Shark 75 that does that. If thats the case and its new you can ask for a replacement. Sometimes a replacement will be fine and sometimes it will have the same problem. All I do to shut down the 75 is go to high throttle and then back to idle quickly. The sudden extra fuel combined with not enough air to burn the fuel causes the engine to flood and kills the engine. [8D]
08-11-2004 | 01:34 PM
#11
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RE: The engine that keeps going
I've never heard of a TT .46 not shutting down. Has anyone else?
I own TT, both Pro & GP, OS AX, GMS, Evo, Magnum 2 & 4-stroke and Tower. The only 2 that won't shut down immediately are the Tower .46-it takes 30 seconds or so and a new Magnum .70 4-stroke-takes a minute to stop. The Tower is on a float plane-how's that for matching an engine to a purpose. The Mag .70 is still in a Big Stick being broken-in.
You might need to let one of your local experts look at the engine and help you tune it. TT .46s are great engines and as you can tell by the number of questions on them here on RCU, there are only rare problems. You may just have one of the 1% that slipped through quality control.
I own TT, both Pro & GP, OS AX, GMS, Evo, Magnum 2 & 4-stroke and Tower. The only 2 that won't shut down immediately are the Tower .46-it takes 30 seconds or so and a new Magnum .70 4-stroke-takes a minute to stop. The Tower is on a float plane-how's that for matching an engine to a purpose. The Mag .70 is still in a Big Stick being broken-in.
You might need to let one of your local experts look at the engine and help you tune it. TT .46s are great engines and as you can tell by the number of questions on them here on RCU, there are only rare problems. You may just have one of the 1% that slipped through quality control.
08-11-2004 | 01:43 PM
#12
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RE: The engine that keeps going
You have an air leak.
The USUAL suspects are:
O-Ring seal between the carb and the engine.
Backplate.
Both of these can easily be remedied. Remove the carb and clean the area underneath where the O-Ring is. Then apply a LITTLE silicon sealer to coat the O-Ring. Press the carb FIRMLY down and WHILE HOLDING THE CARB DOWN tighten the screw(s).
For the backplate it is basically the same thing - remove, clean, a LITTLE silicon and rebolt.
The USUAL suspects are:
O-Ring seal between the carb and the engine.
Backplate.
Both of these can easily be remedied. Remove the carb and clean the area underneath where the O-Ring is. Then apply a LITTLE silicon sealer to coat the O-Ring. Press the carb FIRMLY down and WHILE HOLDING THE CARB DOWN tighten the screw(s).
For the backplate it is basically the same thing - remove, clean, a LITTLE silicon and rebolt.
08-11-2004 | 06:33 PM
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From: Windsor,
ON, CANADA
RE: The engine that keeps going
I'm with Campy, it sounds like air leak around the carb body where it slides into the engine. Evolution engines seem to be famous for this. This little O ring at the bottom isn't a very good design. It's too thin. use the sealant trick. I always use automotive silicone sealants-- ULTRA GREY, BLUE OR COPPER. They work great. Just put a small amount around the carb and on the screw which holds the carb in place in the engine. Do the back plate too. They ususally use cheap gaskets there too.
08-11-2004 | 07:31 PM
#14
Thread Starter
Senior Member
RE: The engine that keeps going
Now, for a curious question.
If there is a leak between the carb and the body, why does it shut off when I put my finger on the carb?? If the leak was there, wouldnt it keep running because the entry point of the leak is PAST where I'm blocking the air?
If there is a leak between the carb and the body, why does it shut off when I put my finger on the carb?? If the leak was there, wouldnt it keep running because the entry point of the leak is PAST where I'm blocking the air?
08-11-2004 | 07:46 PM
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From: Washington,
IL
RE: The engine that keeps going
ORIGINAL: Ed_Moorman
I've never heard of a TT .46 not shutting down. Has anyone else?
I own TT, both Pro & GP, OS AX, GMS, Evo, Magnum 2 & 4-stroke and Tower. The only 2 that won't shut down immediately are the Tower .46-it takes 30 seconds or so and a new Magnum .70 4-stroke-takes a minute to stop. The Tower is on a float plane-how's that for matching an engine to a purpose. The Mag .70 is still in a Big Stick being broken-in.
You might need to let one of your local experts look at the engine and help you tune it. TT .46s are great engines and as you can tell by the number of questions on them here on RCU, there are only rare problems. You may just have one of the 1% that slipped through quality control.
I've never heard of a TT .46 not shutting down. Has anyone else?
I own TT, both Pro & GP, OS AX, GMS, Evo, Magnum 2 & 4-stroke and Tower. The only 2 that won't shut down immediately are the Tower .46-it takes 30 seconds or so and a new Magnum .70 4-stroke-takes a minute to stop. The Tower is on a float plane-how's that for matching an engine to a purpose. The Mag .70 is still in a Big Stick being broken-in.
You might need to let one of your local experts look at the engine and help you tune it. TT .46s are great engines and as you can tell by the number of questions on them here on RCU, there are only rare problems. You may just have one of the 1% that slipped through quality control.
