backfiring and poping

[johno4ne]

89 prostar 190 took it out 2 times with out a problem, then next time out wouldn't start took it home fig out the kill switch was bad so i by passed it started up ran good, took it out a few days later everything was fine then started to ski and i heard this pop and then a few more times then it got really bad and it was poping all the time and and to troll back to the dock. now its poping like crazy. i put new plugs in it the wires were new last year, i adjusted the timing and didnt seem to do anything. it seems to be backfiring out the right side 1-4 it also smells like its running rich

[Skipper]

A single backfire could damage the main valve in the carb (forgot what it is called). If that valve is damaged, it would account for the rough running. Probably in need of a carb rebuild.

[johno4ne]

the power valve? and mine was blown so i bought a new one put it in today same thing and now i think the backfiring blew this one too, the blown power valve could have something to do with the running rich, but i need to find out the backfiring problem so i dont keep running through power valves. the carb is only like maybe a little over a year old.

[DBBOOM]

Have you cleaned/replaced the plugs since the power valve issue? It will,at least, show which cylinders are misfiring. How long since you checked the points/condenser?

[thatsmrmastercraft]

Did you do anything with the plug wires which could have resulted in a couple crossed wires?

[pkreusch]

Hard to tell from your description if its electrical or fuel related. If you have an electric fuel pump, I would certainly look at that system first. If not, then it is certainly electrically related. If you have electronicallcy controlled motor (gt40 or somethinglike that), check the coil, then the pickup in the distributor, etc. Popping ususlly indicates an electrical issue. But don't discount the fuel issue if you have fuel injection. If not, then it is definitely electrical ini nature.
Hope this helps. Good luck!
P..........

[johno4ne]

yes i put new plugs in when i put the new power valve in, i have switched to a electronic dizzy so no more points i did take the cap off and cleaned inside . no i didnt do anything with the wires. it looks like its getting fuel you can smell it, so im thinking probably not the pump. i changed coil and cap still popping, i fig out it is the #4 cylinder that is popping, what would cause it to do that? and how do i fix it

[Luv2Ski]

I am a little confused, is the engine backfiring through the exhaust or sneezing through the carb? A exhaust backfire will not blow the power valve. Any chance the intake valve is not closing off completely in that #4 cylinder, perhaps due to a broken valve spring? Can remove valve cover to check.

If you are running excessively rich, having a fire ignite in the intake is not terribly surprising. Does the problem occur at all RPMs or just at idle?

[pkskier]

Holley has modified their power valve so that backfires to not blow it out anymore. Sounds more like a electrical (firing) problem.

[Luv2Ski]

Originally Posted by pkskier

Holley has modified their power valve so that backfires to not blow it out anymore. Sounds more like a electrical (firing) problem.

Good point. It is technically the carb that Holly changed, not the valve itself; however, in any case since the carb is only a year old it should not blow a power valve. Sounds like you have some other problem that is making you run extremely rich. Check to be sure the PCV is not clogged, unless it is new I would just replace it ($2.50 part).