Backfire Issue

[gvarney13]

Good Evening,

I was out on the lake this weekend and a few times that I killed the engine, it back fired. First time this has happened. Carb been rebuilt recently.

Any ideas?

 

[Haut Medoc]

Re: Backfire Issue

Who rebuilt the carb & is your engine equipped with a water separating fuel filter?......

 

[gvarney13]

Re: Backfire Issue

I rebuilt the carb with help from a freind who is a mechanic and yes I just recently installed a water seperator.

 

[Haut Medoc]

Re: Backfire Issue

Good that you added one, have you checked it?.....
Dump it into a clear container & look......
If you never had one until now, they can fill up fast.....
Have you done any changes with regard to ignition?......
Backfire through the carb is generally either a lean fuel condition or a bad intake valve.......
A compression test would not hurt at this point either.......​

 

[gvarney13]

Re: Backfire Issue

A few months ago I changed to electronic ignition and changed the coil also, but it didnt backfire until I put on the seperator. I also haven't been able to get WOT on 3700 or 3800 RPMs.

 

[Haut Medoc]

Re: Backfire Issue

What was your WOT prior to changing from points?......
I would definately do a compresssion test.....
If you cannot get to 4200 rpm's you have an issue(s).......
It only bacfires when you shut it off?........​

 

[gvarney13]

Re: Backfire Issue

I am not sure what I was getting prior the the change. The reason I changed to electronic was, when I got the boat I did a full tune up on it and stripped out the screws that hold the points down. So I when ahead and changed them out.

And yes it only backfires when I turn off the ignition.