Problem with OS 61FX
03-22-2010, 12:25 AM
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Problem with OS 61FX
Hello Bax:
I have a 61FX that has run great up to last weekend, when it started acting up.
I run the following set-up:
Fuel is 80% methanol and 20% Castor oil mix.
Tuned pipe with 12x8 APC prop which turns at aprox. 12000 rpm
Last weekend it started as normal, idled perfectly but the high end was not stable. The engine acts like its really rich (when pinching the fuel line the rpms immediately go up).
I have to start closing the high speed needle until its less than 1 turn open, in order to reach the usual rpm range. By having the needle in this position the engine will overheat. If I return to the normal setting of between 1,5 and 2 turns the engine only delivers about 9000 rpms and if the engine is left to idle for some time (10-20 seconds) it will die when you throttle up.
I have tried a new glow plug, different fuel, checked the fuel tank for leaks, changed fuel lines but with no luck. I did not make any changes prior to having the problem.
I would really appreciate if you can help me find the source of the problem.
Thanks in advance,
Al
I have a 61FX that has run great up to last weekend, when it started acting up.
I run the following set-up:
Fuel is 80% methanol and 20% Castor oil mix.
Tuned pipe with 12x8 APC prop which turns at aprox. 12000 rpm
Last weekend it started as normal, idled perfectly but the high end was not stable. The engine acts like its really rich (when pinching the fuel line the rpms immediately go up).
I have to start closing the high speed needle until its less than 1 turn open, in order to reach the usual rpm range. By having the needle in this position the engine will overheat. If I return to the normal setting of between 1,5 and 2 turns the engine only delivers about 9000 rpms and if the engine is left to idle for some time (10-20 seconds) it will die when you throttle up.
I have tried a new glow plug, different fuel, checked the fuel tank for leaks, changed fuel lines but with no luck. I did not make any changes prior to having the problem.
I would really appreciate if you can help me find the source of the problem.
Thanks in advance,
Al
03-22-2010, 01:10 AM
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RE: Problem with OS 61FX
Amigo: creo que está usando mucho aceite, yo utilizo una mezcla 6 partes de alcohol metanol por una parte de aceite ricino o sea para simplificar 3 litros de metanol 500 cc de aceite esto reduce a 15% de aceite,tengo mas de veinte años usando ésta mezcla y nunca me han fallado los motores
03-22-2010, 09:14 AM
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RE: Problem with OS 61FX
You will have to re-check your engine. It is possible that it's had an overheat at some time that has caused a problem in the fit between the piston and cylinder liner. Possible dirt ingestion could also cause an erosion of the fit. If the fit is not correct, then the compression will be less than it should be, which will require you to lean the engine to get it to run properly. That's the clue...you had to lean it to keep it running.
03-22-2010, 11:27 PM
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RE: Problem with OS 61FX
Hi Bax:
I disassembled the engine and found the inner parts in good condition. Compression feels quite good, I could not feel any difference (of course this was done with a cold engine).
If the problem is in the piston-cylinder fit, should there be noticeable wear on this parts?
Any other things I should check?
Thanks again for your help,
Al
I disassembled the engine and found the inner parts in good condition. Compression feels quite good, I could not feel any difference (of course this was done with a cold engine).
If the problem is in the piston-cylinder fit, should there be noticeable wear on this parts?
Any other things I should check?
Thanks again for your help,
Al
