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Engine basics => Engine set up tips => Topic started by: Paul Taylor on April 17, 2007, 10:32:59 AM

Title: K&B Greehead - over heats with Muffler
Post by: Paul Taylor on April 17, 2007, 10:32:59 AM

Howdy,
I have a K&B 35. It runs great! Burns less fuel then I thought.
I got a tounge muffler for it and it seems to run hot with the muffler. So I removed it.
Is there a better muffler for these engines? Is there something else I can try with the same muffler?
5/29 is the fuel used, same as I use in the Foxes.

What did I do wrong?

Thanks
Paul

Title: Re: K&B Greehead - over heats with Muffler
Post by: Andrew Borgogna on April 17, 2007, 01:24:59 PM

Paul
Is running without a muffler an option where you fly?  I really believe that the older "pre muffler era" engines run cooler and better without them.  I know my Fox does.  If you can't I would guess something with a larger expansion changer to reduce the back pressure would help.  Something along the lines of a Fox .35 muffler, or drill the holes in your tongue muffler out to a larger diameter.  But I am not an expert, I am just relating what I have observed with my own engines.
Andy

Title: Re: K&B Greehead - over heats with Muffler
Post by: RandySmith on April 17, 2007, 01:33:26 PM

Quote from: rootbeard on April 17, 2007, 10:32:59 AM

Howdy,
I have a K&B 35. It runs great! Burns less fuel then I thought.
I got a tounge muffler for it and it seems to run hot with the muffler. So I removed it.
Is there a better muffler for these engines? Is there something else I can try with the same muffler?
5/29 is the fuel used, same as I use in the Foxes.

What did I do wrong?

Thanks
Paul

Hi Paul

You may try  10% nitro   fuel, as this will allow you to run the motor richer and still have the same power, this will result in the motor running  cooler, Many people have used , and are using this motor with a tongue muffler, so I don't think it can't be done with yours  Try the  10 %  and  even maybe a little more pitch on the prop if youe having to run it  too hard
, and make sure the muffler has about 12 to 15 3-32 holes  opened
Regards
Randy

Title: Re: K&B Greehead - over heats with Muffler
Post by: Bob Zambelli on April 18, 2007, 07:30:33 AM

Paul - You did nothing wrong. We have had similar experiences on a number of older engines, my last being with a Fox .29/tongue muffler.

The one thing you might try is a conventional muffler, which, due to its volume, will allow the exhaust gasses to expand more, dissipating some energy.

Also, what Randy said about fuel makes a lot of sense but just be aware of possible pre-ignition or detonation.

Bob Z.

Title: Re: K&B Greehead - over heats with Muffler
Post by: Paul Taylor on April 18, 2007, 08:49:09 AM

I do not have to use a muffler at the park that we fly at. But sometimes my buddy Louis lets us fly at there club field. We have to use a muffler when we fly out there. I like to play by the rules. y1