Engine hydraulic lock prevention?
09-10-2007, 12:03 PM
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Engine hydraulic lock prevention?
My plane has an OS 46fx engine in inverted configuration. I have been constantly getting hydraulic lock(HL) . An expert in my club tuned it and said to prevent HL I can do this when fueling: Close the fuel line to the carb with a pair of hemostats. Remove the pressure tube from the muffler and drain it to a cup so that when I pump, fuel doesnt get in the engine as well as the muffler . Then connect the muffler line and remove hemostat when I start.This way when I start the engine gets only the fuel/air mixture. This worked fine and I get no HLs anymore. Just wanted to share this idea. What do you engine experts think?
Also , although my engine is well tuned now. I have to tweek the needle (high end) few clicks as the day progresses(gets hotter, humidity changes etc)to prevent engine from dying out when I move the throttle up/down fast. Do you guys do this too..in a single day? Is it true that you always have to Lean it when its hotter , rich it when it gets cooler? Some say "when in doubt richen it". Pls share!
thx
--747
Also , although my engine is well tuned now. I have to tweek the needle (high end) few clicks as the day progresses(gets hotter, humidity changes etc)to prevent engine from dying out when I move the throttle up/down fast. Do you guys do this too..in a single day? Is it true that you always have to Lean it when its hotter , rich it when it gets cooler? Some say "when in doubt richen it". Pls share!
thx
--747
09-10-2007, 01:09 PM
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RE: Engine hydraulic lock prevention?
are you useing a three line fuel tank?i disconnect my fuel line like said but fill through the line to the carburator on my two line tanks.
09-10-2007, 03:38 PM
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RE: Engine hydraulic lock prevention?
Tweeking meaning , I have to change by a few clicks not a whole lot!!! Yes I have a KB idle bar plug.
09-10-2007, 03:49 PM
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RE: Engine hydraulic lock prevention?
You shouldn't need the idle bar even with an inverted engine. I run most of mine inverted with standard plugs.
Re: Hydo-lock.
As long as - Tank height is OK and you CANNOT pump fuel into the carb during fillups, you should have no problems.
Even with a 3 line system, you could be pushing fuel back into the carb/engine during filling.
Try to set things up so that this cannot happen, or at worst unplug the tubing at the engine inlet when you fill.
When you are ready to start the plane, reconnect everything and turn over the prop with the muffler exhaust covered, just until fuel hits the carb itself.
At that point connect the ignitor and crank it over.
Re: Tweaks
Yes this is normal.
As the weather and temp changes I'm adjusting engines a few clicks, at the field, at the start of each flying day.
Re: Hydo-lock.
As long as - Tank height is OK and you CANNOT pump fuel into the carb during fillups, you should have no problems.
Even with a 3 line system, you could be pushing fuel back into the carb/engine during filling.
Try to set things up so that this cannot happen, or at worst unplug the tubing at the engine inlet when you fill.
When you are ready to start the plane, reconnect everything and turn over the prop with the muffler exhaust covered, just until fuel hits the carb itself.
At that point connect the ignitor and crank it over.
Re: Tweaks
Yes this is normal.
As the weather and temp changes I'm adjusting engines a few clicks, at the field, at the start of each flying day.
09-10-2007, 04:36 PM
#7
RE: Engine hydraulic lock prevention?
ORIGINAL: 747
My plane has an OS 46fx engine in inverted configuration. I have been constantly getting hydraulic lock(HL) . An expert in my club tuned it and said to prevent HL I can do this when fueling: Close the fuel line to the carb with a pair of hemostats. Remove the pressure tube from the muffler and drain it to a cup so that when I pump, fuel doesnt get in the engine as well as the muffler . Then connect the muffler line and remove hemostat when I start.This way when I start the engine gets only the fuel/air mixture. This worked fine and I get no HLs anymore. Just wanted to share this idea. What do you engine experts think?
Also , although my engine is well tuned now. I have to tweek the needle (high end) few clicks as the day progresses(gets hotter, humidity changes etc)to prevent engine from dying out when I move the throttle up/down fast. Do you guys do this too..in a single day? Is it true that you always have to Lean it when its hotter , rich it when it gets cooler? Some say "when in doubt richen it". Pls share!
thx
--747
My plane has an OS 46fx engine in inverted configuration. I have been constantly getting hydraulic lock(HL) . An expert in my club tuned it and said to prevent HL I can do this when fueling: Close the fuel line to the carb with a pair of hemostats. Remove the pressure tube from the muffler and drain it to a cup so that when I pump, fuel doesnt get in the engine as well as the muffler . Then connect the muffler line and remove hemostat when I start.This way when I start the engine gets only the fuel/air mixture. This worked fine and I get no HLs anymore. Just wanted to share this idea. What do you engine experts think?
Also , although my engine is well tuned now. I have to tweek the needle (high end) few clicks as the day progresses(gets hotter, humidity changes etc)to prevent engine from dying out when I move the throttle up/down fast. Do you guys do this too..in a single day? Is it true that you always have to Lean it when its hotter , rich it when it gets cooler? Some say "when in doubt richen it". Pls share!
thx
--747
09-17-2007, 11:03 AM
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RE: Engine hydraulic lock prevention?
Hi experts!
I have noticed that although I get Hydraulic locks(HL) sometimes, I do have instances when the Starter would not be able to turn the prop and hits a hard resistance. Someone from my club said that if you cant turn it by hand at all then its a HL. If you can turn it by hand by applying a bit pressure, it is just that the starter didnt have enough Torque in it!
Is this true? Pls share.... if the prop is hard to turn , how do I determine if its a HL or not?
Also when using starter should I turn the prop clockwise first (facing the front of plane) until it hits resistance, then start it? Or should I do the opp. ie turn it Anti-clockwise until it hits resistance, then start it?
Should I switch on the starter and then touch the nose?
Thanks
747
I have noticed that although I get Hydraulic locks(HL) sometimes, I do have instances when the Starter would not be able to turn the prop and hits a hard resistance. Someone from my club said that if you cant turn it by hand at all then its a HL. If you can turn it by hand by applying a bit pressure, it is just that the starter didnt have enough Torque in it!
Is this true? Pls share.... if the prop is hard to turn , how do I determine if its a HL or not?
Also when using starter should I turn the prop clockwise first (facing the front of plane) until it hits resistance, then start it? Or should I do the opp. ie turn it Anti-clockwise until it hits resistance, then start it?
Should I switch on the starter and then touch the nose?
Thanks
747
09-17-2007, 11:10 AM
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RE: Engine hydraulic lock prevention?
if you do have it too full of fuel (the cause of hydro lock) and you bang on it with the starter, you run a pretty good risk of damaging the piston or rod. you should be able to turn it over by hand. if you can't, take the glow plug out, disconnect your fuel line and hit it with the electric starter for a couple good turns to blow the fuel out the glow plug hole. you should be able to put the plug back in and start it right up at that point. if you are having issues with hydrolock, i would take it real easy on priming the engine. that will only add fuel to your problem if it is getting overprimed.
09-17-2007, 11:32 AM
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RE: Engine hydraulic lock prevention?
Hi!
Seems you haven't set the idle needle correctly!
And...you should use a non idle bar plug!...like the OS 8 or Enya 3.
I hope you use 5-10% nitro and a 11x6 or 12x4 APC or RAM prop.
Seems you haven't set the idle needle correctly!
And...you should use a non idle bar plug!...like the OS 8 or Enya 3.
I hope you use 5-10% nitro and a 11x6 or 12x4 APC or RAM prop.
09-17-2007, 11:50 AM
#11
RE: Engine hydraulic lock prevention?
ORIGINAL: 747
Hi experts!
I have noticed that although I get Hydraulic locks(HL) sometimes, I do have instances when the Starter would not be able to turn the prop and hits a hard resistance. Someone from my club said that if you cant turn it by hand at all then its a HL. If you can turn it by hand by applying a bit pressure, it is just that the starter didnt have enough Torque in it!
Is this true? Pls share.... if the prop is hard to turn , how do I determine if its a HL or not?
Also when using starter should I turn the prop clockwise first (facing the front of plane) until it hits resistance, then start it? Or should I do the opp. ie turn it Anti-clockwise until it hits resistance, then start it?
Should I switch on the starter and then touch the nose?
Thanks
747
Hi experts!
I have noticed that although I get Hydraulic locks(HL) sometimes, I do have instances when the Starter would not be able to turn the prop and hits a hard resistance. Someone from my club said that if you cant turn it by hand at all then its a HL. If you can turn it by hand by applying a bit pressure, it is just that the starter didnt have enough Torque in it!
Is this true? Pls share.... if the prop is hard to turn , how do I determine if its a HL or not?
Also when using starter should I turn the prop clockwise first (facing the front of plane) until it hits resistance, then start it? Or should I do the opp. ie turn it Anti-clockwise until it hits resistance, then start it?
Should I switch on the starter and then touch the nose?
Thanks
747
09-17-2007, 03:41 PM
#12
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RE: Engine hydraulic lock prevention?
I'm not clear how you get a hydraulic lock in an inverted front intake engine. When fuel comes into the carb doesn't it just drip out onto the ground/ That has always been my experience.
09-17-2007, 04:47 PM
#13
RE: Engine hydraulic lock prevention?
ORIGINAL: Jim Thomerson
I'm not clear how you get a hydraulic lock in an inverted front intake engine. When fuel comes into the carb doesn't it just drip out onto the ground/ That has always been my experience.
I'm not clear how you get a hydraulic lock in an inverted front intake engine. When fuel comes into the carb doesn't it just drip out onto the ground/ That has always been my experience.
09-17-2007, 06:22 PM
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RE: Engine hydraulic lock prevention?
I either disconnect the carb line and fuel through that or use a fueling valve that cuts the flow of fuel to the carb when filling the tank. I also only use 2-line setups as I've never had a situation yet that required 3. I'm not knocking 3-line setups, just never neededone yet. also I'm curious as to why some people are advising against using idle-bar type plugs. Have used almost nothing but for a long time with no problems.
09-17-2007, 06:38 PM
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RE: Engine hydraulic lock prevention?
Slimline excel fuelers prevent fuel from going toward the carb even if your tank level is off, and work great. No need for 3 line tanks. Always disconnect the pressure line from the muffler when fueling to know when it's full. I run most of my engines pumped so I just have a vent and no muffler pressure. I run OS type F glow plugs in everything. My OS 120 4 stroke pump engines have to be tweeked almost every flight. But, then again it is a 40 to 50 degree difference on average between morning and noon time.
09-19-2007, 08:12 AM
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RE: Engine hydraulic lock prevention?
I use those plastic fuel line clamps a lot of the heli guys use. I have my fill line T'd off (nott ticked-off) on the carb line and pinch the hose to the carb with the plastic pincher thingy. I just unplug the muffler line and use that for overflow releif. I could have installed a 3-line system, but didn't feel like digging out the fuel tank. I use a fuel dot (the thing to plug up the fuel lines) on the fill line when flying, now that I think about it I could use another hose clamp instead.....
-Shane
-Shane
09-20-2007, 05:42 PM
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RE: Engine hydraulic lock prevention?
hey shane, how's flyin over there on okinawa? i almost got a set of orders there not long ago. i may still end up there eventually. any problems with gettin glow fuel or parts/kits etc?
10-09-2007, 05:12 PM
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RE: Engine hydraulic lock prevention?
ALTHOUGH LOTS ON HERE WILL DISAGREE WITH GLOW YOU ARE SIMPLY SETTING YOUR SELF FOR PROBLEMS INVERTED period.seldom have I seen two strokes run well inverted unless glow assist REGARDLESS of tank location.I dont care what you say.
you must be having some large temperature fluxes . usually its not neccesary to constantly be tweeking the H.S. needle daily.
you must be having some large temperature fluxes . usually its not neccesary to constantly be tweeking the H.S. needle daily.
05-31-2023, 10:01 AM
#20
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Hi Gents,
I am having trouble with my Force 46 engine, it can be running okay and then drop the revs to around 3k rpm, it idles for some time and cuts out, so then I reconnect my glow starter and attempt to start my Force 46, using my Hangar 9 electric starter, I sometimes get hydraulic lock(HL) whereby the starter can't turn the engine over because the cylinder is full of liquid fuel. I then have to remove the glow plug, close off the HS needle and then using an electric starter to turn the engine over for at least for a minute. Initially, a fountain of fuel comes blasting out of the cylinder head. I have even had it where the entire crank case is full of fuel and it's coming out of the carb when hand cranked.
Through experience, I found that turning the engine over by hand first just as a check that the engine has not HL, is a good idea.
I notice some get HL when filling the tank with fuel, I'm not experiencing this, during running, my hs needle is about 2 turns open and the idle mixture screw is correctly set.
I am having trouble with my Force 46 engine, it can be running okay and then drop the revs to around 3k rpm, it idles for some time and cuts out, so then I reconnect my glow starter and attempt to start my Force 46, using my Hangar 9 electric starter, I sometimes get hydraulic lock(HL) whereby the starter can't turn the engine over because the cylinder is full of liquid fuel. I then have to remove the glow plug, close off the HS needle and then using an electric starter to turn the engine over for at least for a minute. Initially, a fountain of fuel comes blasting out of the cylinder head. I have even had it where the entire crank case is full of fuel and it's coming out of the carb when hand cranked.
Through experience, I found that turning the engine over by hand first just as a check that the engine has not HL, is a good idea.
I notice some get HL when filling the tank with fuel, I'm not experiencing this, during running, my hs needle is about 2 turns open and the idle mixture screw is correctly set.
