1650 Muffler Glows Orange in Cold

cleon001 · #1 12-11-2010, 05:29 PM

We installed a NEW Cub Cadet muffler on one of our 1650s back last spring. We have found it consistently backfires upon turning it off but other than that runs well. We confirmed with Cub Cadet we have the correct muffler.

I had the tractor out running it just to run it last week and noticed a orange glow circle about 2 inches in diameter on the muffler where the muffler hooks up to the engine. I had never seen this before but due to it only being about 18 degrees out I noticed it. Is this normal? We have another 1650 with the original muffler still intact and that one didn't glow orange in the cold like this one did and doesn't backfire upon turning it off. Any advise and guidance is appreciated.

Thanks
Cleon

Matt G. · #2 12-11-2010, 05:31 PM

The carb may be set too lean, or the timing might be off.

_DX3_ · #3 12-11-2010, 07:12 PM

Double check your timing per Matt's instructions at this link:

http://mgonitzke.net16.net/tools/static_timing.pdf

BCDSFCRET · #4 12-11-2010, 07:28 PM

Your cubs muffler under load will get orange or cherry red. Back in the day when plowing with my dads farmall M you could almost read a news paper through the muffler.

aagitch · #5 12-11-2010, 09:33 PM

It sounds like it's getting too hot I also think it may be the timing or running too lean. You don't want it backfiring when you shut it off it'll cause damage.

Matt G. · #6 12-11-2010, 09:40 PM

Quote:

Originally Posted by BCDSFCRET

Your cubs muffler under load will get orange or cherry red. Back in the day when plowing with my dads farmall M you could almost read a news paper through the muffler.

This isn't a Farmall. I have had a lot of Cubs and worked many of them quite hard, and I have never seen a muffler glow on any of them. Something is not right.

ol'George · #7 12-11-2010, 10:37 PM

I'd for sure go at least 1/2 turn richer (CCW) on the main jet and see what happens, and as Others said, check the timing, it is easy for the points to wear and/or loose proper setting. I have seen them glow a dull red when under a hard Load but not usually.
I'd error to the rich side with this unleaded junk that they sell today for gas. Let her cool down a few minutes before you shut it down, and it won't explode in the muffler.

young enthusiest · #8 12-11-2010, 11:42 PM

Just wanted to say I fought "fuel air mixture" problems last year on my 1650 for about 9 months. Muffler glowed at idle and it backfired all the time. I got real good at setting a carb... But it wasn't the carb. The timing gap was .008. It's supposed to be around .018- .020. I set the timing according to Matt's guide... Voilà no more red muffler or backfiring. Just my .02 lol (pun intended)

thenrie · #9 12-12-2010, 05:55 PM

I found about timing too far advanced on a '66 Ford pickup a long time ago. My dad was driving up Salt River Canyon in Az when it began backfiring and finally got so bad he pulled over and raised the hood. In the dark he could see both exhaust manifolds glowing red. Turned out the distributor had slipped and advance the timing. He turned the distributor back a bit, just eyeballing, and finished his trip, but as soon as he could he reset the timing properly.

I think a too-narrow gap on your points would equate to advanced timing, firing the spark before it should (see previous post).

cleon001 · #10 12-12-2010, 10:28 PM

Thanks for all the input. Once it warms up a little here I am going to check into the points and follow MattG's directions he put together on tuning. I have never worked on the points or tuning before so I am sure I will have more questions when I get further into it.

Thanks again.

Cleon01