back fire out carb
 

I have a 1050 dominator on a 525sc. When trying to start the motor it will start then try and dye off. I have to pump the throttle to try and keep it from dying. If I dont catch it it will back fire out the carb and kill. Trying to start it after it back fires is difficult. It turns over for ever without even firing. Boat runs great after it does start. Anyone have any ideas. The boat used to start great, I would pump it twice when cold and it would fire right off. When warm, would just hit the key and it would idle great. Now I have to give it gas and pump it all of the time even warm.

Mark

Re: back fire out carb
 

Did you check the timing ?

Re: back fire out carb
 

That sounds like a "lean" pop to me.

Try and back out the idle mixture screws about the width of a flat head screw driver and see what happens. Or check the adjustment and the condition of the accelerator pump.

Power Valve maybe??

Re: back fire out carb
 

Yep, timing was the first thing I checked. Right on the money.

Re: back fire out carb
 

I am going to the river in the morning. I will check on the accel pump, making sure that it is working ok. If that dont work, then I will check on some power valves.

Thanks for your input guys.

Re: back fire out carb
 

My 525sc has acted like that a couple times. First time was when I had coil get weak. Fouled the plugs and idled like crap, hard to start and backfire out the carb. You may have blown the powervalves and now its flooding.
Another time it acted similar was when I was running it on the hose. I was on a slight downhill slope. Made the fuel bowl levels different and fouled the plugs also.

Re: back fire out carb
 

are you sure the timing isn't 180* out ?

Re: back fire out carb
 

If his timing was 180 out, it would not even run.

My 454/425HP was doing this same thing last year. The first start of the day was a b#%ch, I would have to pump the hell out of the throttle to get her to fire, then it would cough thru the carb, and just puke. It would take several tries to get it going. Then once she got going, it was fine the rest of the day. I left it like that at the end of the season. On thing I did notice this season was I had a leaking intake valve. Im not sure if this is what caused the starting problem, but it just might have. Just for the hell of it, run a compression test and see if you show any low readings. Only takes 20 minutes or so to do it.

Re: back fire out carb
 

Another thought, let it sit over night. When you get there in the morning, pump the throttle while looking in the carb(do not crank over first). If you dont see gas squirt out from the accelerator pump, you may have a leaky carb, that is leaking after it sits for a while, fouling the plugs, causing the hard starts.

Re: back fire out carb
 

Sounds to me like you have a gummed up carb. If you have to pump it to keep it running, it may be because it's getting too much gas for the amount of air that it is getting with the butterflies closed.

I'm assuming that this is the first time this season that you put it in the water and fired it up? The gas nowadays is crap, and turns to varnish pretty quickly.

If you take it out and open it up for a while, it may clear itself up. I've had the problem before, and used Lucas Tune-up in a Bottle to fix the problem.