I have a .45 Fox engine that is leaking near the front bearing (not sure). Whenever I increase the throttle it starts leaking but stops at idle. Anyone no where it might be leaking? I think its at the bearing but can not take it apart, does anyone no how to take it apart?

suggest you find a replacement bearing 1st. a leaker is better than no bearing at all. also do you or a buddie have a bearing/ bushing puller. ever tried it before? they can be miserable. dick

Bushing bearing or ball bearing version? (Fox made both if I remember correctly...)

Ball bearing isn't as bad to replace the bearing as bushing type. Either can be done... but the bushing type is such a hassle you usually just junk the engine.

The pressure in the engine case gets higher at high throttle than at idle... so leaking more at high throlttle is common when the bearing is starting to fail. The next symtom will be an unstable idle or inability to idel slow enough to not have the model sit in place without holding it. While its just leaking and not bothering idle... you just have a bit of a fuel loss.

You can't pull the crankshaft without pullig the piston. If its a sleved engne, you have to pull the cylinder sleeve to get the piston out... which means you will be dissassembling EVERYTHING. It is best to get some in-person assistance with this the first time you do it... unless you are willing to trash the engine if you goof.

Here is a pretty good site for working on rc engines even though its rc cars its similiar.
http://www.rcnitro.com/rn/articles/ht_rebuild.asp
I haven't looked there for quite a while so I am just hoping it is what you need.
Al

If by leaking you mean fuel coming out of the front bearing then there is nothing wrong with that. This shows that the front bearing is getting lubricated. All of my racing engines have fuel coming out of the front bearing. The time to start worrying is when nothing comes out of the front.

Why would fuel coming out of the bearing mean the bearing is shot. There is nothing to stop it.

Ed S

How old or more appropriately, how used is this engine?

It probably is leaking at the bearing. It’s very likely a bushing bearing too, which is far from top of the line performance.

As long as the engine is running fine I wouldn’t worry about it.