J3-60 Piper Cub 81" 4 stroke .91 engine beginner's questions
02-17-2011, 08:11 PM
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RE: J3-60 Piper Cub 81
ORIGINAL: mike109
G'day
I have several Saitos and I find them easy to start, easy to tune and generally easy to get along with. BUT the one you have is a very powerful beast and not really one I would want to start learning with.
That said, this is how I start and tune my Saitos.
Firstly, you won't be able to get a really good idle until the engine has had at least 20 to 30 minutes running and possibly more. Also, it is best to put it in a test stand to run it in. Even just bolting it to a large piece of wood is better than having it in the plane.
STARTING.
1. Fill the tank, make sure the fuel lines are connected properly to the carby and the muffler.
2. With the throttle at least partly open (if it is closed this won't work) put your finger over the end of the muffler and while watching the fuel line turn the engine over. This will push fuel down the fuel line to the carby. Two or three turns is usually enough to prime the engine.
3. Turn the engine over two or three times (4 or 6 rotations - it is a four stroke).
4. Apply the glow starter and from now on stay away from the prop with your hands.
5. Wind the engine backwards until you feel compression. I do this with a chicken stick or I just push it with the starter.
6. Set the throttle to about 1/4 or slightly less throttle.
7. Apply the starter. 9 times out of 10 the engine will start. If it does not repeat steps from #2.
RUNNING IN.
Your engine has AAC construction. It has an Aluminium piston running in an Aluminium cylinder which is hard Chromed. The piston has an iron ring. The piston ring needs to fit the cylinder better than it does when it comes out of the factory and also the big end and small end bushes have to be polished to work and last well. So initially the engine should have short very rich runs and you may have to leave the glow started connected to keep it running.
I use the Dave Hobbs method of engine running in. 10 minutes really rich at about 4000 RPM, 10 minutes rich at about 6000RPM. At this point you can start to adjust the low speed needle but you should not try for a perfect idle yet. 10 minutes at 8000RPM slightly rich. You can then do a near full power run for another 10 minutes but at this point I usually fly the plane set rich.
When you are tuning the needles, turn them in (clockwise) a small amount and listen for a change in revs. If it goes up you are on the right track. If it does not change, you have gone as far as you should. It is as lean (least amount of fuel to air) that it should be. You should then richen it slightly so you hear the revs drop slightly. To tune the low speed needle, adjust the high speed needle to its absolute peak for revs then adjust the low speed needle very gradually for best revs. Then repeat the high speed, and then the low speed until you get the best revs at each end. You have to adjust the low speed with the throttle set as close to idle as you can get for its current setting. Once they are both set then open (richen) the high speed to drop the revs slightly. This allows for the fact that the fuel pressure drops slightly as the tank empties and will prevent dead sticks. Saitos will happily run quite rich at both ends and it is best to leave them rich for at least the first hour of their life.
Hope his helps a bit and is not too confusing. It is something that has take me years to learn and you will take a while to be come good at it. In the meantime, remember that rich is safe. Lean is engine death. It really is that simple.
Mike in Oz
TUNING.
1. With an unknow engine, I start with the needle valve (high speed needle or HSN) about three or four turns open. Saitos are not critical about this. Leave the low speed needle (LSN) where it was from the factory initially. It will be very rich usually and this helps with running the engine in.
G'day
I have several Saitos and I find them easy to start, easy to tune and generally easy to get along with. BUT the one you have is a very powerful beast and not really one I would want to start learning with.
That said, this is how I start and tune my Saitos.
Firstly, you won't be able to get a really good idle until the engine has had at least 20 to 30 minutes running and possibly more. Also, it is best to put it in a test stand to run it in. Even just bolting it to a large piece of wood is better than having it in the plane.
STARTING.
1. Fill the tank, make sure the fuel lines are connected properly to the carby and the muffler.
2. With the throttle at least partly open (if it is closed this won't work) put your finger over the end of the muffler and while watching the fuel line turn the engine over. This will push fuel down the fuel line to the carby. Two or three turns is usually enough to prime the engine.
3. Turn the engine over two or three times (4 or 6 rotations - it is a four stroke).
4. Apply the glow starter and from now on stay away from the prop with your hands.
5. Wind the engine backwards until you feel compression. I do this with a chicken stick or I just push it with the starter.
6. Set the throttle to about 1/4 or slightly less throttle.
7. Apply the starter. 9 times out of 10 the engine will start. If it does not repeat steps from #2.
RUNNING IN.
Your engine has AAC construction. It has an Aluminium piston running in an Aluminium cylinder which is hard Chromed. The piston has an iron ring. The piston ring needs to fit the cylinder better than it does when it comes out of the factory and also the big end and small end bushes have to be polished to work and last well. So initially the engine should have short very rich runs and you may have to leave the glow started connected to keep it running.
I use the Dave Hobbs method of engine running in. 10 minutes really rich at about 4000 RPM, 10 minutes rich at about 6000RPM. At this point you can start to adjust the low speed needle but you should not try for a perfect idle yet. 10 minutes at 8000RPM slightly rich. You can then do a near full power run for another 10 minutes but at this point I usually fly the plane set rich.
When you are tuning the needles, turn them in (clockwise) a small amount and listen for a change in revs. If it goes up you are on the right track. If it does not change, you have gone as far as you should. It is as lean (least amount of fuel to air) that it should be. You should then richen it slightly so you hear the revs drop slightly. To tune the low speed needle, adjust the high speed needle to its absolute peak for revs then adjust the low speed needle very gradually for best revs. Then repeat the high speed, and then the low speed until you get the best revs at each end. You have to adjust the low speed with the throttle set as close to idle as you can get for its current setting. Once they are both set then open (richen) the high speed to drop the revs slightly. This allows for the fact that the fuel pressure drops slightly as the tank empties and will prevent dead sticks. Saitos will happily run quite rich at both ends and it is best to leave them rich for at least the first hour of their life.
Hope his helps a bit and is not too confusing. It is something that has take me years to learn and you will take a while to be come good at it. In the meantime, remember that rich is safe. Lean is engine death. It really is that simple.
Mike in Oz
TUNING.
1. With an unknow engine, I start with the needle valve (high speed needle or HSN) about three or four turns open. Saitos are not critical about this. Leave the low speed needle (LSN) where it was from the factory initially. It will be very rich usually and this helps with running the engine in.
First of all. I want to thank you so much and I want to tell you that I really appreciate your time to help me. I almost lost hope in getting any help but now I am so glad that there are still good people out there who love to help like your self.
I will follow your instructions in the morning and will let you know the results.
Thank you very much again and I wish you a good night
02-18-2011, 05:45 AM
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RE: J3-60 Piper Cub 81
Is your muffler pressure line getting crimped? If it runs when raised, it might have been getting crimped in the lower position. That would cause a vacuum in the tank giving a short run and starve out. Try removing the pressure line and opening the needle a little more to let the carb suction work better.. That engine will run quite happily without muffler pressure. Done it many times. If it runs then, you can free up the line and reattach it.
02-18-2011, 08:01 PM
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RE: J3-60 Piper Cub 81
I took the engine off the plane this morning and placed it back on the mount. I will do the rest of the work in the morning and will post the results.
02-19-2011, 08:13 PM
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RE: J3-60 Piper Cub 81
Ok, I followed the instructions and everything went fine. I started the engine and kept it running for three full tanks and adjusted it in the mean time. After that I re-mounted it on the plane and the same thing happened, it didn't want to start. I did a lot of reaserch online and found that almost everyone who had the same issue was due to mounting the engine inverted. I also called a local hobby shop and they said that the reason is thatthe engineis inverted and advised me to mount it side ways. Also almostall the online links came with the same advise so I took off the engine and mounted it side ways. But by the time I was done it was 7PM. I've spent 7 hours working on this engine so I decided to shut down for the night and continue in the morning.
I will keep you posted.
I will keep you posted.
02-19-2011, 09:31 PM
#55
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RE: J3-60 Piper Cub 81
So you at least know you have a good engine now. That's a start. Some inverted engines need onboard glow to run right. Before doing anything else, you might try running it inverted with your glow driver attached. If that fixes it, you'll know your lines are good. Then it'll be a simple decision to either change your mounting to make it run without onboard glow, or add an onboard setup to keep it the same.
02-20-2011, 12:00 PM
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RE: J3-60 Piper Cub 81
I think I know why it didn't want to start earlier. I think I have a bad glow driver. When I connect it right after charge it starts but when the engine stops, I connect it again but it doesn't start and there is no sound of combustion like the first time.
I will buy a new glow driver and will try again but I am sure it is the driver.
I will keep the engine mounted side ways. I feel this position is much easier than the inverted one.
I will keep you posted and will post a video soon.
I will buy a new glow driver and will try again but I am sure it is the driver.
I will keep the engine mounted side ways. I feel this position is much easier than the inverted one.
I will keep you posted and will post a video soon.
02-20-2011, 04:50 PM
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RE: J3-60 Piper Cub 81
Is it normal for the plane to be covered in fuel after each run? mostly under and on the side of the muffler.
The glow plug driver is not bad. It is me. I found out that I am not priming enough but at the same time it seems too hard for the feul to flow from the tank to the carb. So I had to turn the prop many time quickly to force the fuel to move and stay in the carb. Is that correct or am I doing some weird things hear?!!
I dont know any more. I think I will have to spend too much time and money to learn.
Is it possible to buy a bigger nitrocontainer? maybe 5 gallons or so?
Anyway, I installed the cowl and here is a video http://www.youtube.com/watch?v=tfTIdUX7lCU
02-20-2011, 08:03 PM
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RE: J3-60 Piper Cub 81
Hang in there, be patient. This is part of the hobby. If it was easy, everybody could do it. [8D]
Let's start by saying you should secure the plane before running the engine. You need to tie the tail down. There are various tiedown devices available. Some guys use the biggest screwdriver they own and stick it in the ground, leaning at a slight angle away from the tail. Then get some rope or heavy twine (clothesline from the hardware or home supply store is best) and secure the tail to the screwdriver. Leave a little slack in the rope, but make sure the knots are very secure! The rope should be looped around the base of the screwdriver, go under the tail, up and over the fuse just ahead of the stab and return under the stab to the screwdriver. It's always good to have a helper hold the airplane while you run it, have them stand to the side away from the exhaust.
Look back at the replies, there was mention of the carb centerline versus the fuel tank centerline. It's important that they be within 1/2 inch of each other. Too high is better than too low, but lined up is best. Too high and the engine will run rich, and may drain fuel when parked. Too low, the engine will run lean and will have frequent stops (deadsticks). By carb centerline, we mean the needle valve center. You may have to move the fuel tank, but it's worth the effort to get it right.
As for a good glow driver, I get a D-cell holder from the car section at the local hobby store (LHS). It holds an alkaline battery like a Duracell. Keep your present glow driver and keep it charged, but the alkaline is a great backup. It's a little hotter, 1.5 volts versus the Nicad glow driver's 1.25 volts. Will last all season.
One reason the engine starts harder in the plane is because the fuel tank is lower while the tailwheel is on the ground. Put something under the tailwheel, even a cardboard box under the tail area to raise it slightly. The fuel can be a bit messy, that's why the electric guys call them 'slimers'. Again, it's just part of the hobby. Paper towels are cheap. Get in the habit of wiping the worst off after every flight, and do a thorough cleaning at the end of the day. I mix a little alcohol (4-6 oz./gal.) in windex to help cut the oil. Don't let the fuel stay on the plane, it can creep under the covering.
Keep at it! Do you have a club or LHS nearby?
Let's start by saying you should secure the plane before running the engine. You need to tie the tail down. There are various tiedown devices available. Some guys use the biggest screwdriver they own and stick it in the ground, leaning at a slight angle away from the tail. Then get some rope or heavy twine (clothesline from the hardware or home supply store is best) and secure the tail to the screwdriver. Leave a little slack in the rope, but make sure the knots are very secure! The rope should be looped around the base of the screwdriver, go under the tail, up and over the fuse just ahead of the stab and return under the stab to the screwdriver. It's always good to have a helper hold the airplane while you run it, have them stand to the side away from the exhaust.
Look back at the replies, there was mention of the carb centerline versus the fuel tank centerline. It's important that they be within 1/2 inch of each other. Too high is better than too low, but lined up is best. Too high and the engine will run rich, and may drain fuel when parked. Too low, the engine will run lean and will have frequent stops (deadsticks). By carb centerline, we mean the needle valve center. You may have to move the fuel tank, but it's worth the effort to get it right.
As for a good glow driver, I get a D-cell holder from the car section at the local hobby store (LHS). It holds an alkaline battery like a Duracell. Keep your present glow driver and keep it charged, but the alkaline is a great backup. It's a little hotter, 1.5 volts versus the Nicad glow driver's 1.25 volts. Will last all season.
One reason the engine starts harder in the plane is because the fuel tank is lower while the tailwheel is on the ground. Put something under the tailwheel, even a cardboard box under the tail area to raise it slightly. The fuel can be a bit messy, that's why the electric guys call them 'slimers'. Again, it's just part of the hobby. Paper towels are cheap. Get in the habit of wiping the worst off after every flight, and do a thorough cleaning at the end of the day. I mix a little alcohol (4-6 oz./gal.) in windex to help cut the oil. Don't let the fuel stay on the plane, it can creep under the covering.
Keep at it! Do you have a club or LHS nearby?
02-20-2011, 08:08 PM
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RE: J3-60 Piper Cub 81
A micro fiber towel from the auto parts store is much better than paper towels for cleaning glow residue. It actually lifts it off instead of smearing it around.
02-20-2011, 09:20 PM
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RE: J3-60 Piper Cub 81
Thank you allso much forthe help.
I actually attached a rope to the concrete block thatI've used for the external mount so the plane is very secured when running. About the centerline of the tank with the carb, it is about center except that the tank CL is a bit lower. I will raise the tail next time before I start however I want to understand how is that not going to effect the engine while in flight since the plane is going to be moving in all directions?
I have a bag of microfiber towels that I will use to clean theplane after running.
Thank you all for the helpful advises. Please be patient with me.I will not give up till I learn it allvery well.
I actually attached a rope to the concrete block thatI've used for the external mount so the plane is very secured when running. About the centerline of the tank with the carb, it is about center except that the tank CL is a bit lower. I will raise the tail next time before I start however I want to understand how is that not going to effect the engine while in flight since the plane is going to be moving in all directions?
I have a bag of microfiber towels that I will use to clean theplane after running.
Thank you all for the helpful advises. Please be patient with me.I will not give up till I learn it allvery well.
02-20-2011, 09:34 PM
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RE: J3-60 Piper Cub 81
I never hand flip a nitro engine. If you crack the throttle and put an electric starter on it, it pulls the fuel up to the carb in a couple of sec and starts. Get an aluminum spinner and a cheap starter and you'll be in tall cotton. I use a old car battery and put a trickle charger on it once a month or so.
02-21-2011, 06:00 AM
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RE: J3-60 Piper Cub 81
The best oil remover I have found is called Krud Kutter. I get it in Lowe's paint dept. I have also seen it at Walmart. The oil just floats off the surface and runs down. Amazing stuff! Doesn't hurt the covering. Paper towels will work, but they are abrasive. Over time the covering can get dull with tiny scratches. 100% cotton fabric works well. Old T-shirts, etc.
02-21-2011, 09:03 AM
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RE: J3-60 Piper Cub 81
I will raise the tail next time before I start however I want to understand how is that not going to effect the engine while in flight since the plane is going to be moving in all directions?
Do have an instructor and a buddy box for the first few flights. They turn into a pile of sticks in seconds!
02-21-2011, 01:03 PM
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RE: J3-60 Piper Cub 81
Do yourself a huge favor and get a tachometer such as this one from Hobbico. 4-stroke engines are very difficult to tune by ear so a tach is the best way to insure you aren't setting your high-speed needle too lean. On my Saito .80 I adjust it for peak RPM then back off (open) the needle until the RPM drops by 200-300. Doing this makes sure that the engine doesn't lean out (draw too little fuel) in the air or when the fuel level in the tank is low. Lean runs are not healthy for any engine, but are especially bad for 4-strokes.
Another thing you want to do is use after-run oil. Basically at the end of your flying session make sure you run the engine dry at full throttle so that no fuel remains in it. Then you add the after-run oil (search the "Glow Engines" forum here on RCU) to the engine and turn it through to make sure it's distributed. Doing so will keep your engine in top shape for years.
Oh, and don't worry about the engine being a bit over-powered for your Cub. Nice thing about throttles, they can always be pulled back. I used to fly a Goldberg Cub with my Saito .80 around at 1/3 throttle for very scale performance, but still had the rest of the power for making it do very UN-cubby things!
Another thing you want to do is use after-run oil. Basically at the end of your flying session make sure you run the engine dry at full throttle so that no fuel remains in it. Then you add the after-run oil (search the "Glow Engines" forum here on RCU) to the engine and turn it through to make sure it's distributed. Doing so will keep your engine in top shape for years.
Oh, and don't worry about the engine being a bit over-powered for your Cub. Nice thing about throttles, they can always be pulled back. I used to fly a Goldberg Cub with my Saito .80 around at 1/3 throttle for very scale performance, but still had the rest of the power for making it do very UN-cubby things!
02-21-2011, 01:13 PM
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RE: J3-60 Piper Cub 81
Oh ya, if you hear a low pitch moan from your plane in the air, slow down and pull up. You will only get sound a couple of times before something falls off the back of your plane!
02-21-2011, 05:09 PM
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RE: J3-60 Piper Cub 81
Thanks to all
Here is today's work. I have spent a lot of time trying to figure out how to move this tank higher to match the CL . Finally I came up with this idea. I have an old wing from a smaller cup so I cut a section of this wing and shaped it with a dremel to fit in the hole behind the engine and from the inside I attached a peice of balsa wood to support the section. Finally I attached a small pad to the section so I can secure the tank on it and all went as planned.
I ran the engine today without any problems and the fuel consumption was perfect. The engine runs without the glow starter and it doesn't hesitate at all.
Here are two videos for todays work. Please send me any comments or suggestions.
Here is today's work. I have spent a lot of time trying to figure out how to move this tank higher to match the CL . Finally I came up with this idea. I have an old wing from a smaller cup so I cut a section of this wing and shaped it with a dremel to fit in the hole behind the engine and from the inside I attached a peice of balsa wood to support the section. Finally I attached a small pad to the section so I can secure the tank on it and all went as planned.
I ran the engine today without any problems and the fuel consumption was perfect. The engine runs without the glow starter and it doesn't hesitate at all.
Here are two videos for todays work. Please send me any comments or suggestions.
02-21-2011, 07:56 PM
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RE: J3-60 Piper Cub 81
I bought the Tachometer today.this one from Hobbico It was $24.99 from a LHS. Will try it tomorrow.
02-22-2011, 03:45 PM
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RE: J3-60 Piper Cub 81
Thats exactly what I am doing 
Today I have adjusted the engine RPM with the Tach and kept the needle at 8700 since the high peak was 9000. Everything is working fine. I put the wings on and all is complete now.
In the end of the video I show the tip of the prop with a tiny crack . It is so tiny.Do you guys think this is bad?
Here is the video http://www.youtube.com/watch?v=fTTb19XlStc
Today I have adjusted the engine RPM with the Tach and kept the needle at 8700 since the high peak was 9000. Everything is working fine. I put the wings on and all is complete now.
In the end of the video I show the tip of the prop with a tiny crack . It is so tiny.Do you guys think this is bad?
Here is the video http://www.youtube.com/watch?v=fTTb19XlStc
02-22-2011, 04:59 PM
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RE: J3-60 Piper Cub 81
G'day
With respect to that crack in the prop - I would not run the engine with it like that. If the fragment decided to part company with the prop you or some one else could end up with it embedded in them. It is very small, and at the tip so you could sand the prop to remove it and do the same on the other side or better, get a new prop.
I think the biggest problem you are going to have with that model is simply that the 91 is really grossly too much for it. It will fly but I have a similar sized cub which I have flown with engines ranging from an OS Surpass 40 (enough and very scale), an Enya 46 4c (similar to the OS 40 but slightly more powerful), an OS 52 Surpass (perfect), an ASP 61 four stroke (perfect plus a bit) and an OS Surpass 70 (too powerful and too heavy). My cub is, I suspect, quite a bit heavier than yours as it was built from a kit and covered in Solatex cloth covering.
I would be very gentle with the throttle on take off. I suspect it will easily take off on about 1/4 throttle and too much may have it torquing its self into the ground. That is quite a serious engine your have there. You will also probably find that the large prop will create quite a deal of thrust even when the engine is idling and this will make the model want to float and not land when you want it to. You will have to have the idle nice and low and stable to get around this or else use a lower pitch prop. Also, a Master Airscrew, while not a great prop, may be your helper here by being less efficient AND being tougher. With all that engine it will be more than enough. And the white paint on the tips is an added safety feature. APC props a great but they completely disappear when they are running which can be a hazard.
I also hope the wing joiner is good and strong. With all that power, you do risk ripping the wings off. I keep reading of Kadet Senior ARFs with 90 four strokes coming apart in the air. I fly mine with an Enya 53 though I did briefly put an ASP 90 four stroke in it and I quickly took it out as it was obvious that it would be easy to overstress the airframe with all that engine.
Go gently, and you should be OK. And enjoy.
Now if you want something for that engine for which it would be a better match, how about a Great Planes Big Stick 60 or a Sig Four Star 60?
With respect to that crack in the prop - I would not run the engine with it like that. If the fragment decided to part company with the prop you or some one else could end up with it embedded in them. It is very small, and at the tip so you could sand the prop to remove it and do the same on the other side or better, get a new prop.
I think the biggest problem you are going to have with that model is simply that the 91 is really grossly too much for it. It will fly but I have a similar sized cub which I have flown with engines ranging from an OS Surpass 40 (enough and very scale), an Enya 46 4c (similar to the OS 40 but slightly more powerful), an OS 52 Surpass (perfect), an ASP 61 four stroke (perfect plus a bit) and an OS Surpass 70 (too powerful and too heavy). My cub is, I suspect, quite a bit heavier than yours as it was built from a kit and covered in Solatex cloth covering.
I would be very gentle with the throttle on take off. I suspect it will easily take off on about 1/4 throttle and too much may have it torquing its self into the ground. That is quite a serious engine your have there. You will also probably find that the large prop will create quite a deal of thrust even when the engine is idling and this will make the model want to float and not land when you want it to. You will have to have the idle nice and low and stable to get around this or else use a lower pitch prop. Also, a Master Airscrew, while not a great prop, may be your helper here by being less efficient AND being tougher. With all that engine it will be more than enough. And the white paint on the tips is an added safety feature. APC props a great but they completely disappear when they are running which can be a hazard.
I also hope the wing joiner is good and strong. With all that power, you do risk ripping the wings off. I keep reading of Kadet Senior ARFs with 90 four strokes coming apart in the air. I fly mine with an Enya 53 though I did briefly put an ASP 90 four stroke in it and I quickly took it out as it was obvious that it would be easy to overstress the airframe with all that engine.
Go gently, and you should be OK. And enjoy.
Now if you want something for that engine for which it would be a better match, how about a Great Planes Big Stick 60 or a Sig Four Star 60?
02-22-2011, 07:11 PM
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RE: J3-60 Piper Cub 81
I agree with you. I think this engine is too powerful for this frame. I keep watching the tail shaking too much when running. I don't know what is going to happen but I will join a new club soon and I have a name of an instructor who I will ask to check it out before I fly. worst case if it crash, then I will buy a bigger one or even switch to a different plane. I just like the cub and never had any other models.
If it crash, do you think the engine will survive?
If it crash, do you think the engine will survive?
02-22-2011, 08:38 PM
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RE: J3-60 Piper Cub 81
Mike109 is quite accurate. The prop should be changed out. The MA he recommends is very good. As far as the wing holding up, I think the wing will hold up fine but the rear mount itself will probably fail first. I wrecked my first CG Cub fuse, was moving and had to pitch the wing. Tried to break it over my knee a few times, gave myself a bruise! I had to put it between a door and the frame to break it, even then it was all I could do to break it, and I'm a big guy. Very strong wing!
Just take it easy flying it, ease in the throttle slowly on takeoff and keep the power low in descents. Is it on the recommended Center of Gravity? If it is, just fly it for now and shop for a good used .60 four-stroke. Mine had an OS 61 FS, and wasn't really overpowered.
Just take it easy flying it, ease in the throttle slowly on takeoff and keep the power low in descents. Is it on the recommended Center of Gravity? If it is, just fly it for now and shop for a good used .60 four-stroke. Mine had an OS 61 FS, and wasn't really overpowered.
02-22-2011, 09:51 PM
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RE: J3-60 Piper Cub 81
OkI have twoquestions.
1- I am going to buy Master Airscrew 15X4 K do you think this is a good one?
2- I think the engine is tuned however when its on idle sometimes it seems like its going to shut off and when I give a little throttle it goes back normal. what do you suggest for me to do in order to keep a nice idle without worrying about shutting down?
Thanks a lot
1- I am going to buy Master Airscrew 15X4 K do you think this is a good one?
2- I think the engine is tuned however when its on idle sometimes it seems like its going to shut off and when I give a little throttle it goes back normal. what do you suggest for me to do in order to keep a nice idle without worrying about shutting down?
Thanks a lot