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johno4ne
06-30-2010, 08:25 PM
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
06-30-2010, 09:15 PM
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
06-30-2010, 10:57 PM
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
06-30-2010, 11:55 PM
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
07-01-2010, 01:31 AM
Did you do anything with the plug wires which could have resulted in a couple crossed wires?

pkreusch
07-01-2010, 01:54 AM
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
07-01-2010, 12:13 PM
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
07-01-2010, 01:23 PM
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
07-01-2010, 01:36 PM
Holley has modified their power valve so that backfires to not blow it out anymore. Sounds more like a electrical (firing) problem.

Luv2Ski
07-01-2010, 02:00 PM
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).

thatsmrmastercraft
07-01-2010, 02:06 PM
Might be time for a compression check.

oldairboater
07-01-2010, 02:28 PM
Compression check.

Gofast
07-01-2010, 02:29 PM
Also, check the dist cap. Make sure the bolt is not lose and the dist did not move. Look for craks or carbon trails in the cap.

Other already mentioned firing order.

Good luck,

Rob

johno4ne
07-01-2010, 03:40 PM
ok i found by taking the wires off one at a time that it was my #4 cyl the backfiring has stopped when i messed with the timing or cleaned the cap on of the 2. so i took the valve cover off and the back rocker not sure if thats the intake or the exhaust was real loose and the washer was broke on it replaced the washer and tighted it up, now the poping is gone, so i think the popping was due to that being to loose and not moving that valve. now the question is there something thing i should put in the oil just to help remove any build up or anything like that? or anyother things i should check or look at? thanks

johno4ne
07-01-2010, 03:50 PM
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).

thats what i have read but holley said if u can screw the air fuel mix screws all the way in and it doesnt die then your PV is blown well i had them all the way in and it was still running. thats why i think that the this one is blown too

Gofast
07-01-2010, 04:04 PM
now the question is there something thing i should put in the oil just to help remove any build up or anything like that? or anyother things i should check or look at? thanks


How many hours on the motor? Are you talking sludge buildup in the motor?

Unless you have a lot of hours, there should not be any build up to speak of, There are all kinds of things you can add to the oil to help with build up. Getting into the shade tree mechanic part of my life here. This is not for the faint of heart. If the motor is running fine, just change the oil on a regular basis. Don't worry about the build up.

If you are getting ready to rebuild the motor, then I can help. Drain the oil, add 1 gallon of diesel to the motor in place of the oil. Let it run for about 5 mins. Oil pressure light will come on, motor will clatter, all sludge will be in the oil pan. The motor will look brand new when you tear it down. I would not recomend this on a motor you do not intend to tear apart. I would use sefoam or one of the other additives from Autozone or OrRileys instead.

Good luck

Rob

johno4ne
07-01-2010, 04:19 PM
there are like 1500 hours on it, the motor has run great until now, im just wondering how that rocker got loose and broke the washer. it being loose i guess i could see how it would break the washer. i put Lucas in when i changed the oil at the end of the season last year. i am def a shade tree so i just want to make sure there isnt something that i should do to the rocker or the valve or something. the last thing i want to do is over look something and then something major happen.

Gofast
07-01-2010, 04:30 PM
I would say you are fine. Just double check the rockers on both sides to make sure none of them are backing loose. They really should back out, but since one did, double check the rest.

Sounds like you are on the right track and it should be running good now.

Thnaks Rob

dgilbreath
07-16-2010, 12:02 AM
From Holley Website:
If you have a carburetor older than 1992 (or you have experienced
an extreme backfire) and expect a blown power valve,
use this simple test. TEST: At idle turn your idle mixture screws
(found on the side of the metering block) all the way in. If your
engine dies the power valve is not blown.

thatsmrmastercraft
07-16-2010, 12:28 AM
Huh, never new that. Just goes to show what a little reading will get you.

Luv2Ski
07-16-2010, 10:45 AM
I had difficulty with the valves staying adjusted on one of my engines due a few nuts that would loosen on their own. Several companies make locking rocker nuts that will grantee you will not have a repeat experience. You simply adjust the nut and then tighten down a set screw in the top. They look like this: