Hummel 2400 General Discussion

[WesRagle]

Hi Guys,

The Hummel engine comes standard with a Zenith carb.



While it may be "old fashion", it is easy to tune. The main jet is controlled by the T handle at the aft/bottom of the carb.

The proceedure per Scott:

Adjust the main jet 3 1/2 turns out. Start and run the engine up to about 3/4 throttle. Turn the main in until the rpm's start to drop. Then turn it out to max rpm and then go another 1/4 turn rich.

That's it. Easy enough, except the person adjusting the carb needs to know the RPM. Since I'll need a timing light for standard maintenance, perhaps I should go ahead and get one that displays RPM so I don't have to communicate with the guy in the cockpit while tuning.

Question: Has someone bought a timing light that they are especially happy with or should I just go to Amazon and pick one?

Thanks for Your Time,

Wes

[Area 51%]

It won't take the place of a timing light for timing, but you might consider a dwell meter. They usually have an RPM scale and can be held in your other hand while fiddling with the mixture screw. Mine's a 1970's unit from Sears (back before they caught Roebuck embezzling).

If you find one like mine, you will have to take a class on how to read a needle crossing a numerical scale.

[sonex1374]

Wes,

You could use a handheld optical tach like the ones used for model airplanes. They don't require any sort of marking or reflector on the prop blades and work fine for big props and small props alike.

https://www.amazon.com/gp/product/B0006N72U2/ref=ox_sc_act_title_1?smid=A1ZHB4F83K0YSQ

These are affordable enough to simply pick one up for general tuning use, or you might be able to borrow one from a model airplane flyer.

Jeff

[WesRagle]

Hi Guys,

Thanks for the replies. Sounds like I don't really need a timing light. I remember having a little trouble when I was trying to get my AeroVee set up for small but equal RPM drops during the "mag check". If I got it set where I was happy at low power I wasn't happy at high power. I seem to remember the secondary timing shifted a bit as RPM was increased. It's a little fuzzy now but I do remember using a timing light and watching as the timing shifted with RPM setting. The solution was to set the timing for minimum drop at high power.

In any event, the mag drop is very small now and I believe Scott sets the timing without the engine running. So, I'll assume that the timing can be checked without running the engine and I just need the small handheld tach for carb tunning.

Thanks Again,

Wes