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Old 09-25-2012, 06:24 PM   #121
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Same problems both engines. I set the speeds needles on optimum where I've ran it at for months and now it won't even crank on this car at the settings. Lsn flush and hsn 1/4 in from three turns out. Its ran great that way for months and months that's what keeps leading me toward something else causing the issue. On the linkage, in the build instructions it shows the throttle servo horn at almost 45 degree angle but the.linkage seems to hit the top radio plate on full throttle. I didn't orient mine that way. I have the servo horn at a 90 degree angle to the servo. Could this be causing a problem even though the throttle returns to idle position when I let off?
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Old 09-25-2012, 06:41 PM   #122
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Take the body off, turn the radio and receiver on. Fixate your eyes on the carb and go from full throttle to full brake. If everything looks right from there focus your energy on full brake to the neutral position. If you are running full blast hitting the brakes and then letting off and the idle raises you have a linkage problem. It takes a bit of playing with but the most important thing is making sure your carb is completely closed when it is supposed to be. Set your servo arm like the manual says and play with the spring tensions on the linkages to keep the throttle where it is supposed to be. These linkages are a bit tricky compared to some more basic designs and take some dialing in.
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Old 09-25-2012, 06:50 PM   #123
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If ts with both motors try the linkage then it can only be what happened to me. Plugged tank filter (it was brand new). This happened the first time I was going to test the car. So don't count this out.
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Old 09-25-2012, 08:54 PM   #124
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If ts with both motors try the linkage then it can only be what happened to me. Plugged tank filter (it was brand new). This happened the first time I was going to test the car. So don't count this out.
What symptoms led you to the tank issue? How could I test this to see if thats the problem?
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Old 09-25-2012, 08:58 PM   #125
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Take the body off, turn the radio and receiver on. Fixate your eyes on the carb and go from full throttle to full brake. If everything looks right from there focus your energy on full brake to the neutral position. If you are running full blast hitting the brakes and then letting off and the idle raises you have a linkage problem. It takes a bit of playing with but the most important thing is making sure your carb is completely closed when it is supposed to be. Set your servo arm like the manual says and play with the spring tensions on the linkages to keep the throttle where it is supposed to be. These linkages are a bit tricky compared to some more basic designs and take some dialing in.
I've been over the linkages 1000 times and they are fine. From full throttle back to idle position, no problem, from brake to servo neutral, no problem, and from full throttle all the way to full brake and back to neutral are good. I increased the throttle return spring pressure and you can see it push the carb slide inward on full brake so there's deffinately adequate pressure there.
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Old 09-25-2012, 09:04 PM   #126
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When I tried the servo horn per the manual position, it just did not look right. When you go full throttle the linkage hits the top of the radio tray and puts it in a bind so I stood it straight up 90 degrees perpendicular to the top of the radio plate. I do have a question though, the ball end mounted to the throttle servo horn that the throttle and brake travel through, how tight should this be in the horn? I have it set up so it spins freely on the horn. Is this correct?
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Old 09-25-2012, 09:42 PM   #127
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Also, does the larger brake disk go on the front or rear? I see a lot of photos with the fuel tank pressure line running around the engine. Do i need to route mine the same way? How long should it be?
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Old 09-26-2012, 11:55 AM   #128
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What symptoms led you to the tank issue? How could I test this to see if thats the problem?
The motor was lean (couldn't find any setup) no matter what I did to it. I tried every thing changed fuel lines verified the linkages. To test it I placed the car on the starter and gave it a go with the fuel line of the motor. Later I blew the pressure line to see if I had pressure or the tank lid was not sealing properly. After everything checked out I blew on the return line and it was hard to blow out of the tank so I determined that the tank filter was clogged. I took it out cleaned and the all the problems went away. the motor then tuned nicely and I race my main of 1 hour without any more problems.
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Old 09-26-2012, 12:59 PM   #129
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Also, does the larger brake disk go on the front or rear? I see a lot of photos with the fuel tank pressure line running around the engine. Do i need to route mine the same way? How long should it be?
If you have a binding problem, then yer discs are back to front. I made the same mistake first time around............

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Old 09-26-2012, 09:07 PM   #130
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If you have a binding problem, then yer discs are back to front. I made the same mistake first time around............

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Nothing's binding, I run the smaller disk on the rear side and the bigger disk towards the front.
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Old 09-26-2012, 09:13 PM   #131
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The motor was lean (couldn't find any setup) no matter what I did to it. I tried every thing changed fuel lines verified the linkages. To test it I placed the car on the starter and gave it a go with the fuel line of the motor. Later I blew the pressure line to see if I had pressure or the tank lid was not sealing properly. After everything checked out I blew on the return line and it was hard to blow out of the tank so I determined that the tank filter was clogged. I took it out cleaned and the all the problems went away. the motor then tuned nicely and I race my main of 1 hour without any more problems.
Ok I tested the tank and i could hear the lid seep air very little, so little that i dont think it will cause any problem. I blew through the pressure line and got a nice stream of fuel pretty easily. Both lines flow good. I wish I had another tank just to try out..
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Old 09-27-2012, 12:39 AM   #132
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Does anyone know why there are no hp specs for the Roma?
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Old 09-27-2012, 01:08 AM   #133
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Also, does the larger brake disk go on the front or rear? I see a lot of photos with the fuel tank pressure line running around the engine. Do i need to route mine the same way? How long should it be?
i have my pressure line short , from the tank to the cooling chamber and to the pipe, i have no,problems at all!

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Nothing's binding, I run the smaller disk on the rear side and the bigger disk towards the front.
You right the smaller disc goes in the rear and the bigger one in the front!

I dont know but i didnt have no issue with my cobra at all. Maybe i have good luck
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Old 09-27-2012, 01:20 AM   #134
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i have my pressure line short , from the tank to the cooling chamber and to the pipe, i have no,problems at all!



You right the smaller disc goes in the rear and the bigger one in the front!

I dont know but i didnt have no issue with my cobra at all. Maybe i have good luck
Yea that's good. I don't wish this nightmare on anybody. It's driving me crazy I don't know what to do.. I've had the same problem from day one. No matter what I try it just does not work, and swap to a different engine and still have the same problem. It's killing me! Running 41021/9886 pipe combo.
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Old 09-27-2012, 05:03 AM   #135
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Yea that's good. I don't wish this nightmare on anybody. It's driving me crazy I don't know what to do.. I've had the same problem from day one. No matter what I try it just does not work, and swap to a different engine and still have the same problem. It's killing me! Running 41021/9886 pipe combo.
Where do you live? Maybe someone can help you in person.
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