Engine Surging Upon Acceleration w/ Video! 2001 Johnson 115 V4 Looper

[xXTJTHEBOATER95Xx]

2001 Johnson 115 V4 Looper

I bought this boat and engine back in May of this year and it had been running great until about 3 weeks ago. This is when I noticed how it was not wanting to go above around 3500rpm without surging.

I talked to a local mechanic over the phone, he said the to start with the fuel filter, so i bought a new one, this is one that is inside the engine cowl, there isnt one on the gas line from the tank for whatever reason. So I replaced that little white filter but hasn't made a difference.

What do I move to next, My neighbor said it might be a carb, but I don't want to sacrifice this awesome hot summer by ripping them out and cleaning them for a couple days and having to try and re install them, as the engine does fine at lower speeds, like trolling around and sometimes I can get it on plane with a bit of throttle adjustments. Don't get me wrong though, I would eventually like to fix it.


Please watch videos:
View of engine:
Surging Outboard-Hole Shot-Engine View - YouTube

View of tach:
Surging Outboard-Hole Shot-Tach View - YouTube

 

[scottmm73]

Re: Engine Surging Upon Acceleration w/ Video! 2001 Johnson 115 V4 Looper

May be air leaking into the fuel system. Consider running from portable tank to diagnose whether the leaks are at the motor or lines running from the tank to the motor.

Also, fuel leaks may cause this. Check entire system for fuel leaks.

 

[xXTJTHEBOATER95Xx]

Re: Engine Surging Upon Acceleration w/ Video! 2001 Johnson 115 V4 Looper

I will get a portable tank, but how would I check for fuel/air leaks because exactly, I almost feel like it would be easier to replace all the fuel lines than trying to find a small hole/ slit/ in a the line

Thanks for your help btw

 

[Abomb27]

Re: Engine Surging Upon Acceleration w/ Video! 2001 Johnson 115 V4 Looper

I had a problem with air getting into the fuel lines before the fuel pump. I replaced all the fuel lines it's just a good idea especially if they are older. Also I took a wrench and tightened every bolt on the outside of the motor, and tightened the carbs. Most bolts were loose by a 1/4 turn. Try this and see if it helps, it should be done anyway. My ran like a champ after that. You should get to the bottom of the problem before you use it, you could cause alot of damage if you are sucking in air and running the motor with a lean condition.

 

[scottmm73]

Re: Engine Surging Upon Acceleration w/ Video! 2001 Johnson 115 V4 Looper

I will get a portable tank, but how would I check for fuel/air leaks because exactly, I almost feel like it would be easier to replace all the fuel lines than trying to find a small hole/ slit/ in a the line

Thanks for your help btw

Run the line from the portable tank to motor mounted fuel pump. If the problem goes away, more than likely the fuel lines from the pump to your main tank have a problem. If the problem doesn't go away, possibly air getting into the system after the fuel pump. Process of elimination.

To check for fuel leaks have someone else drive while you check the motor for possible fuel leaks.

 

[xXTJTHEBOATER95Xx]

Re: Engine Surging Upon Acceleration w/ Video! 2001 Johnson 115 V4 Looper

Just to give an update on the engine, I just today decided to start it again after I cleaned around the carbs and under the air filter thing,where grease/fuel will build up when tilting the engine up and whatever. When I started it, a big slick of oil or gas or mix formed around the engine, looks awfully bad, not sure where it's coming from. I did look where I cleaned it yesterday and it still looks like I just cleaned it.