Need advice on os max 40 engine

[phinkin]

My grandfather has some old nitro planes that I'm trying to get up and running again. I'm jumping in blind and looking for any advice. Like how can you tell if your engine is bad. I'm working on the os max 40 it was locked up, I put a little of the fuel I bought for it and squirted some around the piston and in the carb it feels like it has compression.

 

[phinkin]

Here are some pictures of the engine hopefully I can get someone to help me tell what all I need for it I need a glow plug looking for a idle plug but not sure why type I need to get for this engine

 

[Finesavageboy2]

I don't really know a lot of stuff about rc planes, but I'll try helping you. with my knowledge you need 4 things to get an engine going: Spark, fuel, air, and compression. now I'm not for sure if a rc airplane uses spark, so I'll cross that one out. one way to check compression is to take out the glow plug and put your thumb on the hole. then you turn it over, and if your thumb is getting pushed out of the hole, it has compression. if it doesn't, your piston rings are allowing the compressed air to sleep through the gaps and into the crank case. if you do all of this and everthing is good, now you put it back together, hook up a fuel system, maybe prime it?, and it show pop off. Again I don't know anything about this so were in the same boat here. If I say something wrong, more than likely someone here will correct me. Also I looked up those parts you need and I found that the best glow plug to run is a #8 os Glow plug. For an idle plug, those are only for four stroke engines from what I've looked up. Do you know if its a 2 or 4 stroke engine? are there any engravings on the engine, so we can try to identify it? pictures would really be appreciated!

 

[phinkin]

I don't really know a lot of stuff about rc planes, but I'll try helping you. with my knowledge you need 4 things to get an engine going: Spark, fuel, air, and compression. now I'm not for sure if a rc airplane uses spark, so I'll cross that one out. one way to check compression is to take out the glow plug and put your thumb on the hole. then you turn it over, and if your thumb is getting pushed out of the hole, it has compression. if it doesn't, your piston rings are allowing the compressed air to sleep through the gaps and into the crank case. if you do all of this and everthing is good, now you put it back together, hook up a fuel system, maybe prime it?, and it show pop off. Again I don't know anything about this so were in the same boat here. If I say something wrong, more than likely someone here will correct me. Also I looked up those parts you need and I found that the best glow plug to run is a #8 os Glow plug. For an idle plug, those are only for four stroke engines from what I've looked up. Do you know if its a 2 or 4 stroke engine? are there any engravings on the engine, so we can try to identify it? pictures would really be appreciated!

Hopefully that will help you if you need better ones let me know