What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

RV7A IO360, detonation ?

These photos look more like during the hot start you flooded the intake and had a fire there. Detonation occurs within the cylinder, under certain (hot, high MP, high compression, low octane) conditions.
 
I had that happen once on a hot start. I no longer hot start with the throttle wide open. It was a backfire that blew mine. I hot start by throttle open 1/2 inch, mixture out and as I crank slowly push in mixture. That seems to work fine and haven?t damaged the air filter since.
 
Yes, that was a backfire/airbox fuel ignition event, not a detonation event.
 
Lots of advice on the internet - some fuel, but not too much is required. The skill is knowing how to achieve that.

You will develop your own technique that works on your airplane.
 
First re-start? I would look at the timing and hook ups to the mags. It looks like it fired advanced.

That could be because the mag switch is grounding the mag with the impulse coupler instead of the non-impulse mag.

The impulse mag may have been timed without releasing the impulse coupling.

If your engine is a "shower of sparks"you could be starting on the advanced points instead of the retard breaker.
 
Seems some people are trying to correct the OP....

Detonation means a multitude of things in the English language.. Since the OP is from Poland my guess English is not his primary language there for it's easy to reason he meant back-fire..
 
Last edited:
Seems some people are trying to correct the OP....

Detonation means a multitude of things in the English language.. Since the OP is from Poland my guess English is not his primary language there for it's easy to reason he meant back-fire..
Reminds me of a situation long ago with a Japanese motorcycle manufacture. Dealers claimed a particular newly released motorcycle had a slight running problem and was back-firing. The OE spent many hours researching and could not replicate the problem. Turned out it was a difference in terminology commonly used in our two different base languages. We should have reported the problem as an after-fire, not a back-fire. One was considered a problem through the exhaust, the other was through the intake.
 
Just a tad too lean. Run the boost pump 1-2 more seconds.

+1 What monkey said...this is backfiring during start from too lean a mixture. You can enrich the mixture buy priming more with boost prior to start, or start with throttle at idle and advance during starting.
 
Backfire

English is not a problem here :) but what do you mean - "did you drill the drain hole in the bottom of the snorkel?"

Where the drain should be located?

Thanks,
Witold

Did you drill the drain hole in the bottom of the snorkel?
 
Back
Top