[bradleyban]

Originally Posted by bristolbullit

If you have access to an ignition try that first as it controls spark if it feels like changing the advance it might just do that . As long as the pickup has been set properly . If you have broke a prop definitely look at keyway . Keep it simple one thing at a time

Advance timing won't cause it to run backwards to retarded timing makes them run backwards

[bristolbullit]

Sorry you missed what I was thinking ( lost in translation ) I meant that the ignition is in control of the advance and can scatter the spark where it feels like when malfunctioning . I'm still thinking something mechanical . I wish it would stop raining so we could just fly !

[kip51035]

Sorry "Brad B" , You are wrong! Advanced timing means it is sparking before it gets to top dead center and if you do not spin the prop fast enough it will run backwards. Retarded timing is when it fires after top dead center, which some engines do to make them easier to start. After it starts they use various means to advance the timing. At full RPM some engines are sparking at 30 deg. before top dead center. You have to set your timing with the specks of the ignition module. It might not be the stock module. Just set the pickup lined up like the instructions say at the proper degrees from top dead center and the rest should take care of itself. Improper mixture will sometimes cause an engine to back fire and run backwards. You can check the timing marks by inserting a screwdriver through the spark plug hole and rest it on top of the piston and rotate the engine until it is the farthest out of the hole, then check the top dead center mark. There should be a timing mark Just before the engine gets to top dead center in the direction of normal rotation. Check the magnet and pick up for rust and metal filings.

[bradleyban]

Originally Posted by kip51035

Sorry "Brad B" , You are wrong! Advanced timing means it is sparking before it gets to top dead center and if you do not spin the prop fast enough it will run backwards. Retarded timing is when it fires after top dead center, which some engines do to make them easier to start. After it starts they use various means to advance the timing. At full RPM some engines are sparking at 30 deg. before top dead center. You have to set your timing with the specks of the ignition module. It might not be the stock module. Just set the pickup lined up like the instructions say at the proper degrees from top dead center and the rest should take care of itself. Improper mixture will sometimes cause an engine to back fire and run backwards. You can check the timing marks by inserting a screwdriver through the spark plug hole and rest it on top of the piston and rotate the engine until it is the farthest out of the hole, then check the top dead center mark. There should be a timing mark Just before the engine gets to top dead center in the direction of normal rotation. Check the magnet and pick up for rust and metal filings.

If you timing is too far advance it will cause a backfire and will not sustain a running motor (in reverse) If your timing is closer to TDC 0deg is can run in either direction, Not good but can. Either way the pick up sensor cannot be moved far enough to make it run in these conditions. Either the ignitons is pooched or the keyway under the hub is sheered

[morrisman74]

Hey guys. Just to keep you up to date with my problem. It turns out that desert aircraft was right. I was spinning the prop not all the way threw the motion. Also i was spinning the prop half way down the blade,not at the end of it. I hope this works in the long run. For now everythings good. Thanks again for all your feedback. I will keep you posted.

[bhughes]

My os gt 33 would run backwards right out of the box if I didn't follow through with my swing. It helped if the throttle was up a couple clicks to prevent it

[HAL9KPCM]

Glad you got it figured out!

As for the timing issue, I have to disagree with retarded timing. Retarded timing means that it is firing after top dead center, there is no way that firing after TDC is going to suck the piston back up and reverse direction. Running too far retarded will just have a severe lack of power. The only way retarded timing will force a reverse run would be to retard it so far that you go beyond BDC that you are actually now advanced and this is a very unlikely scenario. I have to agree with Cliff, when it fires before TDC (too far advanced) yes, it will kick it backwards with a backfire and can provide the reverse momentum to continue the cycle and run backwards, although, now it is running with retarded timing.

In the case of not following through with your starting procedure, this makes sense as well. Ignition is advanced and if it is firing before you pull it all the way though TDC, it will again, kick backwards, and if it has enough kick, continue to run backwards.

[bradleyban]

Guys retarded timing it the opposite of normal timing to run forward. look it up. Not making this stuff up

[HAL9KPCM]

Built 3 hot rods, one that ran a 7 second quarter mile, I'm pretty sure I know what advanced timing is... advance fires before TDC, retarded after.

[HAL9KPCM]

Here.. I looked it up: http://en.wikipedia.org/wiki/Ignition_timing

"Timing advance" refers to the number of degrees before top dead center (BTDC) that the spark will ignite the air-fuel mixture in the combustion chamber during the compression stroke. Retarded timing can be defined as changing the timing so that fuel ignition happens later than the manufacturer's specified time. For example, if the timing specified by the manufacturer was set at 12 degrees BTDC initially and adjusted to 11 degrees BTDC, it would be referred to as retarded. In a classic ignition system with breaker points, the basic timing can be set statically using a test light or dynamically using the timing marks and a timing light.

In the example, the spec is 12' before TDC, if you put it to 11, it is firing later than spec, thus it is retarded. If you put it to 13, it is firing before spec, as such, advanced. In my own example, I'm using TDC as spec for example purposes only, you go after TDC, it's retarded, before TDC, it's advanced.