Glow to Petrol conversion?

The engine I'm going to fit into the Hannibal is an OSFS .91 llS-P. It has a fuel pump and a regulator instead of a conventional carburettor. If possible, I'd like to convert the engine to run on petrol. I've been unable to find whether the diaphragm in the regulator can only be used with methanol based fuel. If anyone has converted one of these engines, I'd like to know how it was done.

Might be worth talking to Just Engines, they do a lot of glow to petrol conversions

Brian, someone else asked the same question for the same engine and got a lot of positive answers here: www.rcgroups.com/forums/showthread.php?2...itro-to-gas-ignition Americans asking but apparently the kits are/were in the UK. ;)

I read some of this thread some time ago and came to the conclusion that you need an ignition system rather than running on a glow plug conversion. It's all to do with the mixture ratio as the throttle progresses, although some have done a workaround. Either it works or it don't. (I loved one comment too. "if it works for you then it is good but you only find out if it does when it is in the air" :lol: )

Thanks Chris, I emailed J'EN some time ago, haven't had a reply yet. I think perhaps they aren't interested.

Thanks for the link Phil, unfortunately my engine is different to a standard OSFS.91, so the link refers to a different engine.

I think the conversion work will be extensive as there are many issues.
eg - The seals in the carb & pump may not be Petrol resistant
Changing from Methanol to Petrol means a significant reduction in fuel consumption so it mat not be possible to reduce fuel pump & metering. Another fact that people fail to consider is that reduced fuel thru put means reduced oil thru the engine which means leas heat dissipation leading to overheating The small Evolution 2 stroke petrol motors have to run on a very high oil content because the conrod has plain bearings.



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Thanks Kevin, the petrol resistance of the seals and diaphragm is. the problem. Apart from trying to get hold of a spare seal and diaphragm, and testing them in petrol, I can't see a way of finding out. There doesn't appear to be a definite source of information that I have been able to find. If it comes to the crunch and I can't use the OSFS .91 with petrol, then I'll switch to a Saito 1.25 which is already converted, but I didn't want to use an engine that big in the Hannibal. Although a bit of extra power might come in handy, and flying at reduced throttle means reduced noise, so perhaps going Saito is the best bet.

This guy is very helpful & knowledgable on the Salto gas engines -
www.morrisminimotors.com/gas-engines/sai...-engine-sat17fg.html

Thanks Kevin. I've already fitted a MMM ignition to my Saito 1.25. I contacted MMM about the pumped OS, but they've never fitted their ignition kit to one of those.They are a bit dearer than the offerings of J'EN, but they are so much easier to fit. I've stopped looking for information on the pumped OS now. Fortunately the Saito drops straight into the OS engine mount with no modifications. Should have gone for this engine in the first place.