jonash37

I got a os fs 70 ultimate used and it does run, when try and tune the engine with the glow igniter off it will go from idle to wot no problem. after it reaches wot it has great power but after 5 seconds it starts to slow and then dies like its not getting any fuel. I have readjusted the hi speed and idle mixtures with no luck. If i leave the glow igniter on it stays running and has no problems. anyone have any suggestions for this issue. I have tried 3 new os f glow plugs. Also is it worth putting more money into this engine for a new regulator and/or pump?

maukaonyx

I had one several years ago, had lots of probs like yours, read about all the others having probs here, and gave up. Got a OS 70 Surpass II and never looked back, best 4 stroker I have, and now I have had about 6 of them...all good. There were discussions on this forum about a later version of the 70 Ultimate being fixed, and maybe someone else can help you determine if yours is a hopeless first gen, or the better second gen. You hint at a good solution though. Since yours runs fine and continuously with the igniter, why not install one of the on board igniters to keep her running like it should. You'll pay a small penalty in weight for the extra battery, but your plane might not even notice it. GOOD LUCK! Jon

jonash37

Thats a good idea. i'll get that setup on the engine and let you know.

Gray Beard

My Feedback: (-1)

If you go into the glow engine forum and go into the OS factory support you can ask Bill Baxtor about your engine problem directly. An answer from the head of the service department may be better then from someone like myself. I know my way around the OS four strokes very well but not as well as Bill. When I have a problem I ask Bill. Just a thought.

maukaonyx

Gray Beard, good to see you up and about. Your advice about Bill Baxter is well taken...I have gone to him for help on several occasions. Jon

Gray Beard

My Feedback: (-1)

Up and about is stretching it, the hart is OK though. When I have problems with any of my OS engines I can't figure out myself I go to Bill. Don't always agree with him but this is the net and sometimes you really need to be there to see and hear a problem to solve it. Sometimes I can't describe a problem writing it either. Still, Bax is my go to guy. I have never seen a 70 pumper but with my pumpers it is usually a regulator or pump that has a problem. A small pin hole can cause a lot of odd things to happen.