pulling the plug element in a 21

[RodneyPierce]

Mike, Im assuming that they are asking bowl volume in trying to "gauge" compression. Too much compression, and it will mangle the plug. Obviously, too lean (like we have found out way to many times) and it will eat the element.

I find that when an engine is scavenging like it should, it will pull the element from the plug, but will not break it. Pulled and bunched up towards the exhaust side (like andy stated above) is about perfect TO ME.

 

[Andy Brown]

Andy... in theory, (or whatever).... does pulling the coil achieve gettting the flame front closer to the "bubble" and would it advance the timing ever so slightly?... inherently, i've pulled, and not... and seemed to find it shortens plug life by far?..... Granted i'd not want to be a glowplug in our higher compression engines today. I'm a religious plug watcher, and they do tell the story of whats happening in there, from pulled and good scavenging to black hole stupid mike on the needle..... Steve and Andy both... WHY, was the first question from you guys on what the bowl volume was?... Whats the relationship there?.... inquiring minds.... thanks Mike

Yes it will advance the timing, but by richening the needle you will retard the ignition back, but this time you will burn that "extra" nitro you just put into the cylinder...and therfore make more power.

YES! if you get a good needle with a stock plug and then put in a pulled plug it may burn it out because you are now burning the fuel even better and over heating the chamber. So, you need to richen the needle BEFORE you install a pulled plug.

The pulled plug shortens the flame travel in all directions, because the flame is starting in the center of the chamber and the flame front is not impeded by local metal. The relatively cool metal will actually SLOW the flame front....something you don't want. You want the flame to start in the MIDDLE of the ROOM so to speak, NOT against the wall! This is what the TORRIODAL head design is trying to achive.

Glow plugs do not need a torid head, because we can move the element to the point we want it. Spark plugs need the toriod in order to get the spark gap to the center of the chamber and away front adjacent metal as much as possible. My experience is that the plug actually lasts longer when you pre pull it.

WARNING!!! WARNING!!! WARNING!!! Sometimes the engine will POP and turn over and even sometimes fully start running when you connect the lighter to the glow plug when the plug element is pulled. SO BEWARE! MAKE SURE the PROP is CLEAR BEFORE connecting the Glow Plug lighter.

 

[namba969]

Yup, definetly beware of that pop when running pulled plugs especially when the motor stills hot! I've never acually had one fire back up, but the pop has startled me a few times. The racer that taught me to pull my plugs, used to take his 20 outboard after a run and put the glow igniter on it, whack the flywheel with his hand and fire it back up! He always talked about doing it and I remember calling B.S. on him, well he proved me wrong. Anyways, pulled plugs are the way to go and after I pull a coil or so out I hook up the glow igniter and heat it back up to help make the element last longer.

Andrew Grenier

 

[dwilfong]

My eng start with just the igniter about 30% of the time.

Freaked out John Otto pitting for me at a test run in Brandon with my 1.01 SGX.

Heck once it started backward.

Hold your finger real tight over the plug hole while cranking it over and stop cranking.

sets the piston just right after you get the hang of it. Put the plug in hit it with the igniter and it will fire right up.

Saves battery power. ^_^

David

 

[J_Moore]

Thanks Andy for all that info on this topic. One last thing is when your pulling the plug, do you pull on the first coil or the second or etc to get it where you want it or go deep and pull the whole element out? Just wondering. Thanks in advance

Jeff

 

[mark voorhies]

Thanks guys .i do not know the head volume or clearance .I have tried the HP's terry and it seemed to run colder but i will give it another try later when i am testing.

What i mean by mangled is the element is pulled out and kinda bunched up not always broken and not sucked up in the cavity or missing.

It has been my experience with bad bearing that it will suck the element right out of the plug.This is not the case and all my fittings and couplers and exh gasket seem fine.

I think i am pretty close just had to ask.I also was shown the pull the element trick buy an experienced but young boater...

Yep, sign of a well tuned motor, pipe , prop combo on the element.

Also, the HP's are a cold plug for .67 and up.

A bad bearing will just throw chips from the bad bearings up to the head to break the element off,

usually up inside the plug.

 

[RobertWurster]

can some one please post a pic of a pulled plug to see what it looks like done right ?

 

[Andy Brown]

Thanks Andy for all that info on this topic. One last thing is when your pulling the plug, do you pull on the first coil or the second or etc to get it where you want it or go deep and pull the whole element out? Just wondering. Thanks in advance

Jeff

I pull two coils. If I'm in a hurry, I'll hook the first coil and pull it out until the second coil also comes out of the hole. If not, then I'll hook the second and pull it out further, so it looks like two loops hanging down side by side. Not one above the other. But really it's not critical exactly now it is done. Get two loops out however you can and you got more power. 3-5 mph in some set-ups, plus the throttle response and torque is better. Also for the guys that like to run an idle needle..Richen that too. For those that don't you will notice that the engine will idle better on the beach.

 

[FloridaScaleBoater]

Thanks Andy for all that info on this topic. One last thing is when your pulling the plug, do you pull on the first coil or the second or etc to get it where you want it or go deep and pull the whole element out? Just wondering. Thanks in advance

Jeff

I pull two coils. If I'm in a hurry, I'll hook the first coil and pull it out until the second coil also comes out of the hole. If not, then I'll hook the second and pull it out further, so it looks like two loops hanging down side by side. Not one above the other. But really it's not critical exactly now it is done. Get two loops out however you can and you got more power. 3-5 mph in some set-ups, plus the throttle response and torque is better. Also for the guys that like to run an idle needle..Richen that too. For those that don't you will notice that the engine will idle better on the beach.

"plus the throttle response and torque is better"

Years ago, when I first set up my Thomas SS45,, I could not get it to come back to full throttle after milling slow,,

Jerry Crowther cam over, showed me this same "speed secret" and I have been doing it ever since.

So, if you have a boat that doesn't like to come back after a mill,,, give this a try,,, works great!!!

 

[RobertWurster]

Well i tried this trick to day and wow it worked great.My engine starts way eazyer and idled whitch it never liked to do.I richened it up a bit and she ran a lot smother .Thanx for this tip .I had herd of it years a go but for got all about it.I wont run with out doing this ever agin.I used a little pic i had and it works great.Use a magnifing glass and it helps to see the coils .

 

[Andy Brown]

Well i tried this trick to day and wow it worked great.My engine starts way eazyer and idled whitch it never liked to do.I richened it up a bit and she ran a lot smother .Thanx for this tip .I had herd of it years a go but for got all about it.I wont run with out doing this ever agin.I used a little pic i had and it works great.Use a magnifing glass and it helps to see the coils .

Great to hear about your success Robert!

 

[RobertWurster]

Thanck you Andy and every one else for explaning how to do it for us.It did make a big differance.

 

[Tim Kish]

What would you guys say the most common thing is that pulls the element out of the glow plug and usually mangels it.I head that when you have your pipe set correctly it will pull the element slightly and if it is too lean it will pull it.

The engine is a 7 port from glenn and the pipe is a woods cooper set at 7.5" and the plugs are KB 1L and 50 % nitro in a JAE 21

When i lean on it to get the cackel out of it it runs pretty well but when i check the plug the element is mangeled.

Thanks

Terry

If you are testing in the early spring you need to restrict the water to the engine so it can build enough heat to burn the fuel , you may be leaning on the needle to much in an effort to get the engine to run like your use to and taking the plug out , I have always felt that a pulled plug is a sign that everything is working together.

Tim K

 

[RobertWurster]

Ya tim is right it is still cold here in Or and with the snow run off the water is real cold .i went to a pond and fountain store and got a clamp that is ajustable to limit the water alot.with out it as soon as the cold water hit the head button the motor would die down and stall.LOL it took me a bit of head scratn to figure that one out.

 

[tmunn]

Thank guys and Tim you are correct i do not get that 1-2-3 ok it's hot test like in the summer...lol..our water is only about 40*F so it's cold and the air was cool too.I will restrict the water next time out to bring up the temp and richen up.I never spent much time on it last outing as i had other boats but after some mods to it she runs real nice .

I have other plugs like the HP's and mccoy 9's and odonnel blues.I just need to mess with them more to find the best combo.I find the 1L although not all that tough work the best for starting, milling and best performance until they blow...lol...

 

[Glenn Quarles]

Thank guys and Tim you are correct i do not get that 1-2-3 ok it's hot test like in the summer...lol..our water is only about 40*F so it's cold and the air was cool too.I will restrict the water next time out to bring up the temp and richen up.I never spent much time on it last outing as i had other boats but after some mods to it she runs real nice .

I have other plugs like the HP's and mccoy 9's and odonnel blues.I just need to mess with them more to find the best combo.I find the 1L although not all that tough work the best for starting, milling and best performance until they blow...lol...

Terry, with water and air that cold I would remove the water cooling completely!

Glenn

 

[camaroboy383]

i agree.........

 

[J_Moore]

Thanks Andy for clearing that up.

Jeff

 

[anthony_marquart]

I tested this a bit yesterday.. I was looking at my old plugs that are still good. And I found that many of them has the coil bunched up at the outer edge, and to one side, of the plug. I pulled the coil out on one and ran a few tanks. Ran well,... pulled to plug to look and found that while running it had pulled that plug out even further!!! next run,.. the coil was gone!,.. no damage that I can see to the motor,.. but it was a well used plug. First time in a long time that I had my boat out.. the NR 5port with a lower volume head, I think .17cc (Rodney?) and the Spipe at 7 7/8, and 65% Otto Fuel, is a very nice combination. No problem getting on and off the pipe,.. nice speed,.. big Fun!

 

[tmunn]

ok Glenn, i will try the water unhooked next time out.