Restoring an old engine
06-29-2003 | 05:49 PM
#1
Restoring an old engine
Hi all,
I am after some advice on an old motor of mine.
I left the hobby several years ago and had an old Chinese made (Mutunug) 61 2 stroke motor laying around. This motor had only been used for 5 or 6 flights.
A few weeks ago, I pulled out of the box and found it was partly seized. I left it soaking in glow fuel for a couple of days and then completely disassembled it and put it back together. There was no evidence of rust or corrosion and now it spins freely.
The problems I am now having are several.
The motor leaks fuel by the shaft (at front)
When I try to start the motor, it floods and the prop nut comes loose. No matter how tight I tighten the prop nut, it always works loose. (I am using a plastic spinner and an electric starter).
I don't have the manual anymore and am unable to locate one.
Where should I start with the needle settings?
How can I stop the flooding?
How do I seal the front of the motor?
Any help would be greatly appreciated
APalsson
I am after some advice on an old motor of mine.
I left the hobby several years ago and had an old Chinese made (Mutunug) 61 2 stroke motor laying around. This motor had only been used for 5 or 6 flights.
A few weeks ago, I pulled out of the box and found it was partly seized. I left it soaking in glow fuel for a couple of days and then completely disassembled it and put it back together. There was no evidence of rust or corrosion and now it spins freely.
The problems I am now having are several.
The motor leaks fuel by the shaft (at front)
When I try to start the motor, it floods and the prop nut comes loose. No matter how tight I tighten the prop nut, it always works loose. (I am using a plastic spinner and an electric starter).
I don't have the manual anymore and am unable to locate one.
Where should I start with the needle settings?
How can I stop the flooding?
How do I seal the front of the motor?
Any help would be greatly appreciated
APalsson
06-30-2003 | 01:53 AM
#2
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From: Adelaide, South Australia
Restoring an old engine
It sounds to me like the fuel tank is mounted a bit high and it's syphoning fuel into the carb causing the flooding. Also the needle might be open too far and spinning it over just draws in more and more fuel. A badly flooded engine can start to get a hydraulic lock when spun with an electric starter and then the starter is acting like a spanner on the prop nut trying to undo it.
Make sure the centre of the tank is level with the centre of the carb then close the needle completely. Blow through the fuel line to make sure the needle is actually closed then take out the plug and spin the engine over with the starter to blow out any excess fuel (only spin it until you can't see any vapor coming out of the plug hole). Check that the plug is glowing properly then refit it and see if it'll fire up for a few seconds with the throttle about 1/4 open. If it doesn't start or only runs for a second or so then open the main needle about 2 to 3 turns, give it one turn of prime, or a few drops down the carb, and try again.
I've heard of this engine but don't know much about it. Is it ballraced or plain bearing? Any engine that doesn't use a fully sealed front bearing will leak a little out the front and a plain bearing MUST leak or it's not getting lubricated. For the moment, don't worry about the fuel leaking out the front because it's most likely just a combination of flooded engine and spinning over with the starter.
Make sure the centre of the tank is level with the centre of the carb then close the needle completely. Blow through the fuel line to make sure the needle is actually closed then take out the plug and spin the engine over with the starter to blow out any excess fuel (only spin it until you can't see any vapor coming out of the plug hole). Check that the plug is glowing properly then refit it and see if it'll fire up for a few seconds with the throttle about 1/4 open. If it doesn't start or only runs for a second or so then open the main needle about 2 to 3 turns, give it one turn of prime, or a few drops down the carb, and try again.
I've heard of this engine but don't know much about it. Is it ballraced or plain bearing? Any engine that doesn't use a fully sealed front bearing will leak a little out the front and a plain bearing MUST leak or it's not getting lubricated. For the moment, don't worry about the fuel leaking out the front because it's most likely just a combination of flooded engine and spinning over with the starter.
