AQ225 E Engine Backfire Under Load

[rleip21]

I have a 19ft Bayliner with an AQ225E and 275 Stern drive. The boat idles nicely but as soon as i give it some gas in the water it starts backfiring I imagine through the carb because I here it pop. I recently replaced coil, wires and plugs. Rotor and cap fine. I also replaced fuel filter and put in a fuel water separator. All of this and no luck. One thing that I found was the fuel filter element bottom rusted off and there was a lot of rust in it. I pulled off the filter in the carb and there was rust in about a third of it. All of this and it still backfires. What should I do next? How can I fix it?
Thanks for the help,
Ryan

 

[captmello]

Re: AQ225 E Engine Backfire Under Load

What about the points and condenser? did you replace them? Have you checked the timing?

 

[rleip21]

Re: AQ225 E Engine Backfire Under Load

I have one of those igniter systems so no points. So I will try to adjust timing. Could there be something clogged in carb that would cause it from rust.

 

[rleip21]

Re: AQ225 E Engine Backfire Under Load

One other thing is that it has progressively gotten worse each time I go out. Is that a sign of anything? Since I have no clue how to use a timing gun nor do I own one is it okay just to turn the distributor a little each way to see if that fixes it.
Thanks,
Ryan

 

[captmello]

Re: AQ225 E Engine Backfire Under Load

Since I have no clue how to use a timing gun nor do I own one is it okay just to turn the distributor a little each way to see if that fixes it.
Thanks,
Ryan

I wouldn't. Timing is critical and you could damage the engine.

 

[rleip21]

Re: AQ225 E Engine Backfire Under Load

I think its fixed. I do have to test run it, but I did get a timing light. Very easy to use should have done it a while ago, but the timing was set at 40 when it was supposed to be at 8. So it was way off so I'm crossing my fingers and hoping it works this time. Thanks for the help.
Ryan

 

[captmello]

Re: AQ225 E Engine Backfire Under Load

as long as you got the timing btdc and not atdc, you may have found it. Your advance timing is just as important. Put the timing light back on the motor and rev the engine a bit. the timing should advance further btdc as the engine revs. the advance is controlled by springs and weights in the dist. that can stick, and lead to worse and worse performance...

One other thing is that it has progressively gotten worse each time I go out

If you get it out on the water and the engine is running better, but doesn't reach wot of 4000-4400 rpm, don't push it, again running it out of proper time can damage it further.

 

[rleip21]

Re: AQ225 E Engine Backfire Under Load

I did check the advance and it worked because I thought that was the problem but it worked. I think I did the timing right. It had a tab with white paint on it at 0 and had a tape around the pulley with green lines where the timing should be. I think the guy before me just changed the timing without a light when he bought an electronic ignition conversion kit. Some reason it must of ran okay for a while.