Motor has started backwards a couple times
06-03-2009, 05:52 PM
#1
Race Director
Thread Starter
Motor has started backwards a couple times
It runs backwards, too, not very well, though.
Retard the static timing a few degrees maybe? Set at 10 BTDC now.
Easy enough to set 200 RPM timing to say 4 degrees BTDC or even zero, and still have it at 10 degrees static at 750 RPM idle with the EFI
It has only happened twice,and when hot.
Rather annoying as it pumps the intake and air cleaner full of exhaust,and then of course it wants to flood on restart with no oxygen in the air to burn the gas.
Doug
Retard the static timing a few degrees maybe? Set at 10 BTDC now.
Easy enough to set 200 RPM timing to say 4 degrees BTDC or even zero, and still have it at 10 degrees static at 750 RPM idle with the EFI
It has only happened twice,and when hot.
Rather annoying as it pumps the intake and air cleaner full of exhaust,and then of course it wants to flood on restart with no oxygen in the air to burn the gas.
Doug
06-03-2009, 06:11 PM
#2
Race Director
Member Since: Jun 2006
Location: Inverness FL
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St. Jude Donor '07
usually that happens because of 'kickback' from too slow a cranking speed, too much compression, too much timing; or any/all of the above... 
with the right camshaft, an engine will run in either direction
Bill
with the right camshaft, an engine will run in either direction
Bill
06-03-2009, 08:02 PM
#3
Le Mans Master
....although it wont last very long unless you turn the pistons around to offset the pins for counter rotation and usually have to change the firing order too....
06-03-2009, 08:36 PM
#6
Drifting
Running backwards
Just remember, there is NO OIL PRESSURE if the pump is spinning backwards--in fact, the pump is trying to evacuate any oil that is in all of the passageways and the filter.
RON
06-03-2009, 08:42 PM
#7
Racer
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Hummmmmm......interesting!
My GMPP 454HO will very occasionally try to do something like this
when I go to start it after its been fully warmed up and then sits for
30-60 minutes. It cranks a little slow, won't start, and then when
I let off the key, it coughs and a big puff of white smoke comes up
thru the carbs.
Sounds like maybe backing off the timing a little bit might help?
Any other thoughts?
Thanks!
Don
My GMPP 454HO will very occasionally try to do something like this
when I go to start it after its been fully warmed up and then sits for
30-60 minutes. It cranks a little slow, won't start, and then when
I let off the key, it coughs and a big puff of white smoke comes up
thru the carbs.
Sounds like maybe backing off the timing a little bit might help?
Any other thoughts?
Thanks!
Don
06-03-2009, 09:22 PM
#8
Le Mans Master
Hummmmmm......interesting!
My GMPP 454HO will very occasionally try to do something like this
when I go to start it after its been fully warmed up and then sits for
30-60 minutes. It cranks a little slow, won't start, and then when
I let off the key, it coughs and a big puff of white smoke comes up
thru the carbs.
Sounds like maybe backing off the timing a little bit might help?
Any other thoughts?
Thanks!
Don
My GMPP 454HO will very occasionally try to do something like this
when I go to start it after its been fully warmed up and then sits for
30-60 minutes. It cranks a little slow, won't start, and then when
I let off the key, it coughs and a big puff of white smoke comes up
thru the carbs.
Sounds like maybe backing off the timing a little bit might help?
Any other thoughts?
Thanks!
Don
06-04-2009, 01:57 AM
#9
Race Director
Thread Starter
Yeah, i know about the oil pump.
It doesn't run very long, about long enuf to fire each cylinder maybe 2-3 times before I turn the key off and start over.
Doug
It doesn't run very long, about long enuf to fire each cylinder maybe 2-3 times before I turn the key off and start over.
Doug
06-04-2009, 06:07 AM
#10
Team Owner
06-04-2009, 01:49 PM
#13
Le Mans Master
06-04-2009, 03:21 PM
#15
Drifting
I had a Mercury outboard back in the early 60's that had 2 starters. One started the 2 stroke going forward , one in reverse. This is how outboards motors ran both directions before transmissions were added.
06-04-2009, 04:41 PM
#16
Race Director
06-05-2009, 10:03 AM
#19
Le Mans Master
06-08-2009, 08:12 AM
#20
WOW, I use to tell people this and they would not believe me. This is the first time I have heard someone else talk about it. I still don't understand how it works.
I use to have a dirt bike with a 125cc Sachs engine with a 6 speed. If I was in 1st gear and went up a small incline and rolled the bike back wards while holding in the clutch then let the clutch out at the bottom of the incline while still rolling back wards the bike would go into a reverse mode. I could drive it and shift all the gears but only going in reverse. I had to stall the bike to get it to go forward again. No, I could not ride far in reverse without dumping it.
I use to have a dirt bike with a 125cc Sachs engine with a 6 speed. If I was in 1st gear and went up a small incline and rolled the bike back wards while holding in the clutch then let the clutch out at the bottom of the incline while still rolling back wards the bike would go into a reverse mode. I could drive it and shift all the gears but only going in reverse. I had to stall the bike to get it to go forward again. No, I could not ride far in reverse without dumping it.
