engine surging, stalling ( Please Help)

[mookieo2]

79 140 Johnson just rebuilt carbs and fuel pump. Water tested for a couple of minutes and it ran great, idled smooth, started right up.

Installed motor on different boat, took for a test run and all was well. Newer boat has built in gas tank. When I tested it it was using a red can. Went home put gas in built in tank. New warer separator, fuel lines. I started the boat on muffs and ran it in the driveway. Water tested it and it ran great for 5 minutes. Stalled out then would run fine then start surging and running rough. Boat wouldn't idle. When I would pump the ball fuel would pour out the carbs. Did I bend the floats? Is it maybe some kind of air in the fuel line or water seperator? Did I blow the fuel pump pulling fuel through the new water seperator and lines?

 

[mrcj001]

Re: engine surging, stalling

Re: engine surging, stalling

Check the fuel pick-up tube in the built-in gas tank. Some manufacturers use some sort of cheap vinyl tubing. It could be cracked or even blocked.

Was the tank clean before use used it?

Also, if you are pumping the bulb and the carbs are leaking fuel, then the float is stuck. If you used a Sierra Kit, thats the problem.

 

[mookieo2]

Re: engine surging, stalling

Re: engine surging, stalling

Whats the problem with the sierra kits? I was assuming the floats got stuck, maybe something kicked up from the inboard tank. We didn't clean it. The boat was sitting for a couple of years since I picked it up the other day. When we drained the fuel it looked clean.


I will check the floats tomorrow. we emptied the fuel tank but I'm not sure what was left in it. I will check the filter. We siphoned the fuel out of it and it flowed fine. Am I going to have to remove the floor panel and look at the tube? Ugghhh!

 

[mookieo2]

Re: engine surging, stalling

Re: engine surging, stalling

Found a piece of rubber or something black making the bottom carb float valve stuck open. Took both carbs apart and blew out all the jets and passageways with compressed air. We primed the tank and got fuel to flow good through the new water separator.

Took it to the ramp. Started right up idled well. No problem going forward or reverse. Took it out for a spin. It took off for a while then started to bog down. It would then surge. We could lower the throttle and then give it more throttle or wot and it would keep doing it. It started to hesitate. I looked in the carbs at wot and saw gas spurting out of the jets with the butterflies fully opened. I'm not sure if its supposed to flow smoothly or spurt out. I couldn't watch it long because it would hesitate and slow down. It finally stalled on its own. When we got it started again it felt and sounded like it wasn't running on all 4 cylinders.

 

[mookieo2]

Re: engine surging, stalling ( Please Help)

As usual it was carelessness. In our haste to get everything buttoned up, upon inspection we somehow kinked the fuel line coming from the pump and going to the upper carb. I haven't tried it yet but I'm sure thats it. I will run off a portable tank first to make sure everything is ok.

So far all my frustrations are due to my own faults. I knew I had this thing running well the other morning until something got stuck in the carb float valve. I believe it was a piece of the new fuel line that had fallen in the line.

 

[kevert]

Re: engine surging, stalling ( Please Help)

good read. you are quite the mechanic for sticking with it and not giving up.