Weird Possible Carb Problem
02-10-2010 | 08:37 PM
#26
Senior Member
RE: Weird Possible Carb Problem
ORIGINAL: gunny11
I had a simmilar problem and I found this out when steve51 came over to try my ignition module...... found out it was a brand new plug that was bad. (CM-6) actually a couple of these were bad brand new.
Gunny
I had a simmilar problem and I found this out when steve51 came over to try my ignition module...... found out it was a brand new plug that was bad. (CM-6) actually a couple of these were bad brand new.
Gunny
BCCHI
02-15-2010 | 01:11 AM
#27
RE: Weird Possible Carb Problem
My engine has the hub spun on the shaft and the plug is now firing at nearly bottom dead center! Believe me, it doesn't look spun, It's solid and tracks straight, just not where it's supposed to be.
Pull the plug out, insert it in the High tension lead (outside the motor) insert a Q tip or wood dowel into spark plug hole and rotate crank to find Top dead center . Then look at the position of your magnet. It should be 28-30 degrees passed hall sensor pick up. If not, apply ignition power and rotate the crank until it sparks. Take note of the position of the piston with the q tip. I'll bet your nowhere near where it should be.
Another engine will come, and it'll happen again unless something is changed.
Good luck
R
Pull the plug out, insert it in the High tension lead (outside the motor) insert a Q tip or wood dowel into spark plug hole and rotate crank to find Top dead center . Then look at the position of your magnet. It should be 28-30 degrees passed hall sensor pick up. If not, apply ignition power and rotate the crank until it sparks. Take note of the position of the piston with the q tip. I'll bet your nowhere near where it should be.
Another engine will come, and it'll happen again unless something is changed.
Good luck
R
02-15-2010 | 01:34 AM
#28
Thread Starter
My Feedback: (25)
RE: Weird Possible Carb Problem
WOW! I just remembered something. the last flight of the day the engine was running I had a deadstick landing. the plane was a ways out so couldn't tell a lot, but the engine poped and threw the prop hub! After what you just told me I now suspect the hub must have sheared the pin in flight and that is what killed the engine instantly - amazing! thanks I still have the engine here waiting for the replacement - I'm going to check it tomorrow.
boy, I couldn't wait. Went out and checked - when my piston is at top dead center the magnet pickup is 180 degrees out!
02-15-2010 | 01:38 AM
#29
RE: Weird Possible Carb Problem
ORIGINAL: splais
WOW! I just remembered something. the last flight of the day the engine was running I had a deadstick landing. the plane was a ways out so couldn't tell a lot, but the engine poped and threw the prop hub! After what you just told me I now suspect the hub must have sheared the pin in flight and that is what killed the engine instantly - amazing! thanks I still have the engine here waiting for the replacement - I'm going to check it tomorrow.
boy, I couldn't wait. Went out and checked - when my piston is at top dead center the magnet pickup is 180 degrees out!
WOW! I just remembered something. the last flight of the day the engine was running I had a deadstick landing. the plane was a ways out so couldn't tell a lot, but the engine poped and threw the prop hub! After what you just told me I now suspect the hub must have sheared the pin in flight and that is what killed the engine instantly - amazing! thanks I still have the engine here waiting for the replacement - I'm going to check it tomorrow.
boy, I couldn't wait. Went out and checked - when my piston is at top dead center the magnet pickup is 180 degrees out!
02-15-2010 | 02:13 AM
#30
Senior Member
My Feedback: (4)
RE: Weird Possible Carb Problem
Surprise, surprise...
Been telling people for about 20 years now the key doesn't do anything but tell the engine assembler where to put the hub on the crank...
Keys are soft, if the the hub is loose the key will shear...
Haven't use a key for about 20 years...If the hub taper matches the crank taper and the hub is TIGHT it will never move...Loctite helps, but TIGHTNESS is the secret...
some Chinese engines used cast aluminum hubs with a big wide keyway..The hub cracked because the combination of the wide keyway and tightening was too much for a casting...6061 aluminum works just fine with NO keyway, you just gotta know how to time and engine at assembly...
By the way, thanks for the heads up...When #411 gets here the hub will be the first thing checked..
Been telling people for about 20 years now the key doesn't do anything but tell the engine assembler where to put the hub on the crank...
Keys are soft, if the the hub is loose the key will shear...
Haven't use a key for about 20 years...If the hub taper matches the crank taper and the hub is TIGHT it will never move...Loctite helps, but TIGHTNESS is the secret...
some Chinese engines used cast aluminum hubs with a big wide keyway..The hub cracked because the combination of the wide keyway and tightening was too much for a casting...6061 aluminum works just fine with NO keyway, you just gotta know how to time and engine at assembly...
By the way, thanks for the heads up...When #411 gets here the hub will be the first thing checked..
02-15-2010 | 02:34 AM
#31
RE: Weird Possible Carb Problem
ORIGINAL: Antique
Surprise, surprise...
Been telling people for about 20 years now the key doesn't do anything but tell the engine assembler where to put the hub on the crank...
Keys are soft, if the the hub is loose the key will shear...
Haven't use a key for about 20 years...If the hub taper matches the crank taper and the hub is TIGHT it will never move...Loctite helps, but TIGHTNESS is the secret...
some Chinese engines used cast aluminum hubs with a big wide keyway..The hub cracked because the combination of the wide keyway and tightening was too much for a casting...6061 aluminum works just fine with NO keyway, you just gotta know how to time and engine at assembly...
By the way, thanks for the heads up...When #411 gets here the hub will be the first thing checked..
Surprise, surprise...
Been telling people for about 20 years now the key doesn't do anything but tell the engine assembler where to put the hub on the crank...
Keys are soft, if the the hub is loose the key will shear...
Haven't use a key for about 20 years...If the hub taper matches the crank taper and the hub is TIGHT it will never move...Loctite helps, but TIGHTNESS is the secret...
some Chinese engines used cast aluminum hubs with a big wide keyway..The hub cracked because the combination of the wide keyway and tightening was too much for a casting...6061 aluminum works just fine with NO keyway, you just gotta know how to time and engine at assembly...
By the way, thanks for the heads up...When #411 gets here the hub will be the first thing checked..
I posted in the other thread that I didn't know exactly how this hub is attached. I assumed it had a key but I can't see one for sure. Either way, the spark confirms it's relative position.
I'm really itching to know if it's just pressed/glued or even an interferance fit. if that's the case, a little heat and a little reclock we could be up and running!
How will you check #411? 366 is ROCK solid just completely rotated.
02-15-2010 | 10:43 AM
#33
Senior Member
My Feedback: (4)
RE: Weird Possible Carb Problem
As with EVERY engine I buy, it will be completley dis assembled to check it out, then put back together and tested...With about 6 different size props..No relying on someone's optomistic numbers.....Not worried about any warranty...
The hub will be put back on the crank with some Loctite on the taper or straight shaft, whichever it has...The retaining nut will be as tight as it can get it with my 10 inch socket handle...The crank will be held from turning by a 10mm stopper in the spark plug hole, as sold by brand Z for their engines...Part # 4810-96220, Piston stopper...Brand Z torque for the stud is 80-120 kg.cm, whatever that is...With Loctite...
The engine will be bolted upright on a mill table..The hub will be lightly surfaced using a solid carbide 1/2 inch end mill, to ensure exact 90 degree to the crank sufrace...Not that I don't trust Todd, I'm sure it willl be perfect as delivered...I just do it to ALL my engines...Just in case..
The hub will be put back on the crank with some Loctite on the taper or straight shaft, whichever it has...The retaining nut will be as tight as it can get it with my 10 inch socket handle...The crank will be held from turning by a 10mm stopper in the spark plug hole, as sold by brand Z for their engines...Part # 4810-96220, Piston stopper...Brand Z torque for the stud is 80-120 kg.cm, whatever that is...With Loctite...
The engine will be bolted upright on a mill table..The hub will be lightly surfaced using a solid carbide 1/2 inch end mill, to ensure exact 90 degree to the crank sufrace...Not that I don't trust Todd, I'm sure it willl be perfect as delivered...I just do it to ALL my engines...Just in case..
02-15-2010 | 12:17 PM
#34
RE: Weird Possible Carb Problem
ORIGINAL: Antique
As with EVERY engine I buy, it will be completley dis assembled to check it out, then put back together and tested...With about 6 different size props..No relying on someone's optomistic numbers.....Not worried about any warranty...
The hub will be put back on the crank with some Loctite on the taper or straight shaft, whichever it has...The retaining nut will be as tight as it can get it with my 10 inch socket handle...The crank will be held from turning by a 10mm stopper in the spark plug hole, as sold by brand Z for their engines...Part # 4810-96220, Piston stopper...Brand Z torque for the stud is 80-120 kg.cm, whatever that is...With Loctite...
The engine will be bolted upright on a mill table..The hub will be lightly surfaced using a solid carbide 1/2 inch end mill, to ensure exact 90 degree to the crank sufrace...Not that I don't trust Todd, I'm sure it willl be perfect as delivered...I just do it to ALL my engines...Just in case..
As with EVERY engine I buy, it will be completley dis assembled to check it out, then put back together and tested...With about 6 different size props..No relying on someone's optomistic numbers.....Not worried about any warranty...
The hub will be put back on the crank with some Loctite on the taper or straight shaft, whichever it has...The retaining nut will be as tight as it can get it with my 10 inch socket handle...The crank will be held from turning by a 10mm stopper in the spark plug hole, as sold by brand Z for their engines...Part # 4810-96220, Piston stopper...Brand Z torque for the stud is 80-120 kg.cm, whatever that is...With Loctite...
The engine will be bolted upright on a mill table..The hub will be lightly surfaced using a solid carbide 1/2 inch end mill, to ensure exact 90 degree to the crank sufrace...Not that I don't trust Todd, I'm sure it willl be perfect as delivered...I just do it to ALL my engines...Just in case..
Just guessing from his name
