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Mini 2 Ignition Timing


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This Mini 2 engine has had a problem with excessive heat - big time! The cure - well band-aid approach has been to run it very rich. I think a V8 would be more economical. I have never been a big 2 stoke fan, the sport has brought us together, but not through choice. By my very nature , I cannot leave a problem unsolved. After trying various things, my next move was to investigate the timing. Readily available information for this engine is very poor. Added to that I had no equipment and it seemed extravagent to purchase same for just a one off. This video is my solution to this problem.

Maybe it is the wrong reduction drive for this prop causing excessive heat? They make four different sizes. How do I find the right one? Something else I know nothing about. Can anyone help on this?

If nothing else, it's a learning curve.

Kev

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Thanks for the info.

This engine has blown a hole in the piston 4 times now. I have pressure tested it, run it rich, moved the timing(retarded), tried a smaller prop but the temp still keeps climbing. It may be that it is a 'Friday Engine' , but I hate to admit defeat and would really like to crack this problem even though it has been an unenjoyable, expensive journey.

I do have another motor now, so I can still fly. This engine will have to be an ongoing, headscratching project - but I would love to solve it!

Kev

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Thanks for the info.

This engine has blown a hole in the piston 4 times now. I have pressure tested it, run it rich, moved the timing(retarded), tried a smaller prop but the temp still keeps climbing. It may be that it is a 'Friday Engine' , but I hate to admit defeat and would really like to crack this problem even though it has been an unenjoyable, expensive journey.

I do have another motor now, so I can still fly. This engine will have to be an ongoing, headscratching project - but I would love to solve it!

Kev

Hi Kev

have you checked that the compression is not too high?

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Depending on the type of exhaust, the silencer may be plugging up.

When I broke my mini2 in I was generous (as manual instructs) with oil mix and the result (in about 12 hours run time) was a plugged silencer and lower rpm due to the restriction. Usually this will richen automatically, but it's an avenue you are on your way down now from your last post. Pop some rivets off and check inside if you run the silencer after the tuned pipe.

In winter air here on East Coast Canada:

156 main

6L1 needle (2nd clip from bottom)

Sorry forget needle jet size...

in a Bing 84 keeps my mini2 floating just under 1200 degrees EGT.

Running 3.1:1 with a helix triblade.

I am considering a head duct for summer though:

http://www.aerocorsair.com/id108.htm (thanks Alex)

Do please post the solution when it comes to you.

Good luck with it.

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Depending on the type of exhaust, the silencer may be plugging up.

When I broke my mini2 in I was generous (as manual instructs) with oil mix and the result (in about 12 hours run time) was a plugged silencer and lower rpm due to the restriction. Usually this will richen automatically, but it's an avenue you are on your way down now from your last post. Pop some rivets off and check inside if you run the silencer after the tuned pipe.

In winter air here on East Coast Canada:

156 main

6L1 needle (2nd clip from bottom)

Sorry forget needle jet size...

in a Bing 84 keeps my mini2 floating just under 1200 degrees EGT.

Running 3.1:1 with a helix triblade.

I am considering a head duct for summer though:

http://www.aerocorsair.com/id108.htm (thanks Alex)

Do please post the solution when it comes to you.

Good luck with it.

Or just run it with out the silencer to try (do not take the expansion box off)

Please wear ear protection and dont do it in the back garden for long :shock:

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