Tune problems, need opinions
05-24-2010, 07:57 PM
#1
Tune problems, need opinions
Ok i consider myself a decent tuner, i dont have flame out, My engines last usually 10+ gallons, but this engine has me at a loss.
Its always been picky on tune. Well last saturday i went to tune the engine because it hasnt been ran in a couple weeks and its warmed up. I took it around the track a few laps brought it in and tried tuning it, unless i kept it rich my idle was high, if i lowered the idle it would die, ive tried everything possible, even took it back to little out from flush and tuned again, tried an OD 97T instead of the nova c6tgc. nothing. So last night, i tore the engine apart, bearings feel great, piston was dark but it wiped off. I flushed the needles out, actually flushed the whole engine out with fuel. Inspected all the orings, all good, oiled everything while putting back together. Today i put in in my buggy, at first acted great, started running it at 1/2 a tank, almost ran out of fuel, put more fuel in, got to half a tank and my problems started again. Only thing i can think of is the front bearing is bad, i dont see excess fuel tho. This engine has good compression, not Huge but normal for an engine with 5-6 gallons on it.btw ive tried a new tank, all new lines, new exhaust gasket, new springs, and a new gallon of fuel as well. any tips or opinions would be appreciated
Its always been picky on tune. Well last saturday i went to tune the engine because it hasnt been ran in a couple weeks and its warmed up. I took it around the track a few laps brought it in and tried tuning it, unless i kept it rich my idle was high, if i lowered the idle it would die, ive tried everything possible, even took it back to little out from flush and tuned again, tried an OD 97T instead of the nova c6tgc. nothing. So last night, i tore the engine apart, bearings feel great, piston was dark but it wiped off. I flushed the needles out, actually flushed the whole engine out with fuel. Inspected all the orings, all good, oiled everything while putting back together. Today i put in in my buggy, at first acted great, started running it at 1/2 a tank, almost ran out of fuel, put more fuel in, got to half a tank and my problems started again. Only thing i can think of is the front bearing is bad, i dont see excess fuel tho. This engine has good compression, not Huge but normal for an engine with 5-6 gallons on it.btw ive tried a new tank, all new lines, new exhaust gasket, new springs, and a new gallon of fuel as well. any tips or opinions would be appreciated
05-24-2010, 08:07 PM
#4
Ok i consider myself a decent tuner, i dont have flame out, My engines last usually 10+ gallons, but this engine has me at a loss.
Its always been picky on tune. Well last saturday i went to tune the engine because it hasnt been ran in a couple weeks and its warmed up. I took it around the track a few laps brought it in and tried tuning it, unless i kept it rich my idle was high, if i lowered the idle it would die, ive tried everything possible, even took it back to little out from flush and tuned again, tried an OD 97T instead of the nova c6tgc. nothing. So last night, i tore the engine apart, bearings feel great, piston was dark but it wiped off. I flushed the needles out, actually flushed the whole engine out with fuel. Inspected all the orings, all good, oiled everything while putting back together. Today i put in in my buggy, at first acted great, started running it at 1/2 a tank, almost ran out of fuel, put more fuel in, got to half a tank and my problems started again. Only thing i can think of is the front bearing is bad, i dont see excess fuel tho. This engine has good compression, not Huge but normal for an engine with 5-6 gallons on it.btw ive tried a new tank, all new lines, new exhaust gasket, new springs, and a new gallon of fuel as well. any tips or opinions would be appreciated
Its always been picky on tune. Well last saturday i went to tune the engine because it hasnt been ran in a couple weeks and its warmed up. I took it around the track a few laps brought it in and tried tuning it, unless i kept it rich my idle was high, if i lowered the idle it would die, ive tried everything possible, even took it back to little out from flush and tuned again, tried an OD 97T instead of the nova c6tgc. nothing. So last night, i tore the engine apart, bearings feel great, piston was dark but it wiped off. I flushed the needles out, actually flushed the whole engine out with fuel. Inspected all the orings, all good, oiled everything while putting back together. Today i put in in my buggy, at first acted great, started running it at 1/2 a tank, almost ran out of fuel, put more fuel in, got to half a tank and my problems started again. Only thing i can think of is the front bearing is bad, i dont see excess fuel tho. This engine has good compression, not Huge but normal for an engine with 5-6 gallons on it.btw ive tried a new tank, all new lines, new exhaust gasket, new springs, and a new gallon of fuel as well. any tips or opinions would be appreciated
05-24-2010, 08:17 PM
#6
Just a thought, have you pulled the motor and checked the block for cracks?
05-24-2010, 08:25 PM
#8
are you on the original bearings? Do you have a unusual amount of oil around the front bearing?
that would be my guess on your airleak. I actually had a problem with the pressure nipple on my pipe getting clogged. Took forever to figure that one out.
that would be my guess on your airleak. I actually had a problem with the pressure nipple on my pipe getting clogged. Took forever to figure that one out.
05-24-2010, 08:38 PM
#11
Are you sure the slide is closing all the way? Is your throtle trim set right? Sounds to me like it is running with a high idle and a richer setting which means to me, for what ever reason, when you lean it out on the low and lower the idle it is closing more then you would like it too.
I know it sounds elementary but you never know. If that is not it, i would start at the clutch and work back. I get a cup full of real soapy water, get a brush and wipe it on any part of the engine i am checking a leak at. Then i blow into a piece of fuel tubing that is connected to the carburator. Who knows, might be a carb boot or pinch bolt. You know alot of front bearings leak "a little", but if it is really blowing bubbles that is probably your leak.
I know it sounds elementary but you never know. If that is not it, i would start at the clutch and work back. I get a cup full of real soapy water, get a brush and wipe it on any part of the engine i am checking a leak at. Then i blow into a piece of fuel tubing that is connected to the carburator. Who knows, might be a carb boot or pinch bolt. You know alot of front bearings leak "a little", but if it is really blowing bubbles that is probably your leak.
05-24-2010, 08:42 PM
#12
Are you sure the slide is closing all the way? Is your throtle trim set right? Sounds to me like it is running with a high idle and a richer setting which means to me, for what ever reason, when you lean it out on the low and lower the idle it is closing more then you would like it too.
I know it sounds elementary but you never know. If that is not it, i would start at the clutch and work back. I get a cup full of real soapy water, get a brush and wipe it on any part of the engine i am checking a leak at. Then i blow into a piece of fuel tubing that is connected to the carburator. Who knows, might be a carb boot or pinch bolt. You know alot of front bearings leak "a little", but if it is really blowing bubbles that is probably your leak.
I know it sounds elementary but you never know. If that is not it, i would start at the clutch and work back. I get a cup full of real soapy water, get a brush and wipe it on any part of the engine i am checking a leak at. Then i blow into a piece of fuel tubing that is connected to the carburator. Who knows, might be a carb boot or pinch bolt. You know alot of front bearings leak "a little", but if it is really blowing bubbles that is probably your leak.
05-26-2010, 06:49 AM
#13
Tech Adept
You can find this video here: http://www.youtube.com/watch?v=6xwDy-I0Z4I
He mentions that some gasket material might not be strong enough. Get gasket material that can withstand over 350°F for sealing with just in case.
EDIT: Notice that Squirrel also mentions Team Associated's green slime. It's used for sealing the HSN and LSN.
05-26-2010, 10:21 AM
#14
Tech Adept
This sounds identical to the issues I was having with my DBX. 2 changes that I made at the same time helped significantly. First was a new o-ring on the gas cap. Second was a new glow plug. I am curious to hear if your new bearings help.
05-26-2010, 10:41 AM
#15
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You do mention you checked everything... and I realize this is an obvious one to check... but...
How much play does your conrod have? That sounds JUST like the symptoms of a sloppy conrod.
Also the obvious airleak questions that everyone has covered...
How much play does your conrod have? That sounds JUST like the symptoms of a sloppy conrod.
Also the obvious airleak questions that everyone has covered...