carburetor springs

[hallschuch]

Hi guys,
I started my 912 the other day ( for the first time) and took caution to not allow the throttle to be pulled open by the carburetor springs... I'm not sure I understand why those springs exist... is it a common practice to remove them, or do they serve some unknown (to me) function?

[Dave S]

Karl,

The design purpose of the springs is to assure, that in the event of a throttle cable break or disconnect, the engine goes to full throttle rather than going to idle. The theory is that full throttle is better than no power.

Using a vernier throttle, which is the normal throttle type used with a 912, prevents the throttle from creeping when set to a specific power setting.

My understanding is that very few people experiment with removing the springs.

I have the vernier throttle and after a little getting accustomed to, like it, especially for fine tuning the RPM.

[hallschuch]

Karl,

The design purpose of the springs is to assure, that in the event of a throttle cable break or disconnect, the engine goes to full throttle rather than going to idle. The theory is that full throttle is better than no power.

Using a vernier throttle, which is the normal throttle type used with a 912, prevents the throttle from creeping when set to a specific power setting.

My understanding is that very few people experiment with removing the springs.

I have the vernier throttle and after a little getting accustomed to, like it, especially for fine tuning the RPM.

Thanks Dave, I appreciate the info!

[avidflyer]

I replaced those strong springs with some light duty ones from my local farm and fleet type store. They work fine as far as I can tell. I have the vernier style throttle cable, and just a little bump on the button, and the throttle would jump forward. Kind of always seemd to fight it coming back to lower power settings also. I much prefer what I have now. JImChuk

[jiott]

Another benefit of the springs is that they keep the throttle cable under a slight tension continuously; this helps keep your synchronization accurate and eliminates any slop or push/pull differences. The lightest aftermarket springs from McFarlane have plenty of tension to do all these things. Many,many of us have changed to the McFarlane light springs. They work well even without a vernier throttle, with just the normal friction nut.

[Maverick]

What is the source for these McFarlane springs?
Fred

[Maverick]

I have he friction lock throttle. I'm fine with it versus a vernier type. What drives me crazy is the throttle creep. Plus, to get the engine to really slow down I have to pull on the throttle to hold it out enough to get to idle, otherwise the throttle tries to go in and speeds up the engine. I've become accustomed to it but, I just don't like it. I'm afraid I might pull a cable free from the locking mechanism on the carb. Will these Van's type of springs help with something like this? It sounds like it might.
Fred

[desertdave]

I have he friction lock throttle. I'm fine with it versus a vernier type. What drives me crazy is the throttle creep. Plus, to get the engine to really slow down I have to pull on the throttle to hold it out enough to get to idle, otherwise the throttle tries to go in and speeds up the engine. I've become accustomed to it but, I just don't like it. I'm afraid I might pull a cable free from the locking mechanism on the carb. Will these Van's type of springs help with something like this? It sounds like it might.
Fred

I got so tired of fighting with the factory springs with the friction throttle setup. I pulled the springs off and have been flying without them for the last 9 months. I ordered the Vans springs today and will give you a full report when they arrive. If I have to fight with the Vans springs I'll switch over to a vernier throttle like @desertfox4 has and raves about.

[Delta Whisky]

Maverick - "Van's springs" significantly reduced the creep factor. I still see a tad bit of creep I if lock the throttle (with normal locking pressure) at idle but only to a point. If I lock the throttle at 1800 rpm, where I've set the carb stops, it will creep to about 2000 or 2100 but the creep stops there. I can now lock it at 1800 will a little more twist on the lock. The real benefit for me is that all creep at flight power settings has gone away. The little bit of creep at idle settings bothers me only on the ground; I don't use the lock in the pattern.

Dave - I'm interested in seeing your report. (How well or if your experience is in any way similar to mine.)

[GuppyWN]

I took my springs off 2 years ago. It was one of the first things I did. I won't speak for the factory but I didn't take the springs off in a void.