2004 Johnson 115 V4 running problems

[rkdygert]

I've been trying to get my 2004 Johnson 115hp V4 (J115PLSRC) to run right all season so far and no luck. I was originally working on it in a test tank in the driveway and finally got it pretty good; well, I launched it in the lake yesterday for the first time this season and as soon as I fired it up, I knew it wasn't hitting on all four cylinders.

After some work, I've figured out that the top two cylinders on each side are not firing at all; I can pull the top two plug wires off and there is no change in RPM or power. When I pull the bottom two off, engine dies right out right away.

Compression check is good, new plug wires this season, carburetors were just rebuilt this season, new powerpack a couple of days ago. I haven't checked spark with spark checker but I can hear the spark jumping to the plug when I pull the wire off so I assume it's good (will check later when I get back to the boat with spark checker).

I swapped the bottom ignition coil with top to see if it was the ignition coil; didn't follow the coil. I swapped bottom plugs with top plugs, didn't follow the plugs (new plugs as of yesterday morning too). I'm beginning to get frustrated...

Is there something in the ignition system that would cut ignition to top cylinders only?

And, here's one more thing to throw in the mix; when I was running it in the driveway, I had it on a portable fuel tank...now that it's in the lake, it's back on the boat's internal tank...could it be water in the fuel tank? I pumped some fuel out into a glass container and don't see any water but maybe I'm just not catching it at the right time?

Please HELP!

 

[woody66912]

Re: 2004 Johnson 115 V4 running problems

Spray some fuel at the top two cyl, if they hit then you have a fuel manifold issue or carb problem.

 

[rkdygert]

Re: 2004 Johnson 115 V4 running problems

Thanks woody...I tried spraying fuel directly into the carbs and it picked the cylinders up so I guess it's definitely a carburetor problem.

I can't see anything that would affect only one carb on each side since each side shares a common fuel manifold and input hose from the pump...am i missing something? Or do I just happen to have two (recently rebuilt) carbs that have gotten fouled up somehow?

Ideas on where to go next? Or is it time to strip the carbs off and go through them again?

 

[rkdygert]

Re: 2004 Johnson 115 V4 running problems

I'm hoping somebody can give me some more ideas on this one because it's driving me nuts...

In the lake, the motor will continuously drop out the top two cylinders; I can pull the top plug wires off and no change in RPM.

I followed woody's advice & sprayed fuel directly into the carb throats at which point the cylinders pick right up for a second which leads me to believe it must be a fuel delivery problem (plus compression and spark check good anyway).

I check for water in the fuel, can't find any...took a portable tank with fresh fuel to the marina, didn't help. I tried squeezing the primer bulb while it was running and it seemed to help a little which made me think it could be a bad OMS pump. So, I pulled the boat out of the water and brought it home yesterday thinking I would need to change the fuel pump. I just tried running it on muffs in the driveway so I could test the fuel pump pressure and now it runs on all four cylinders, roughly the same drop in RPM when I pull each plug wire off.

So I ran the pump pressure tests and at idle it puts out ~3-5psi (spec is not less than 3psi). So now I'm not sure if I should think the pump is bad or not?

How would the increased back pressure of being in the water affect fuel delivery? Note that this problem happens in the water at idle and at higher RPM, though I can't get it too high because the motor just wants to stall out.

HELP PLEASE

 

[rogerwa]

Re: 2004 Johnson 115 V4 running problems

My V4 115 only has two carbs. One that services the upper cylinders and one for the bottom. I would start with the carbs and work back toward the plugs. Check your float and all adjustments onthe carb that serves the upper. My guess is you have someting wrong there.

 

[rkdygert]

Re: 2004 Johnson 115 V4 running problems

Mine has four carbs...even more for me to screw up!

I'll double check the floats in the top carbs to make sure they're not set too low...

I also noticed on the parts breakdown that there's a float and valve in the vapor separator that I didn't know about when I rebuilt the carbs...can anyone tell me what this is for and if it could be related to the problems I'm having?

 

[woody66912]

Re: 2004 Johnson 115 V4 running problems

Did you some how miss putting the well gaskets on the high speed pick-up tube that sits in the middle of the float?.
I remember a long time ago i had a 150 giving me the snot. This might be a stretch, but what i found was that one of the high speed pick up-tubes (AKA emulsion tube) was not pushed into the carb body far enough, the outcome of this was that the well gasket would not seal, as the tube would contact the float bowl. The way I diag this was to use a depth gauge and checked a running cyl /carb for the height.

 

[rkdygert]

Re: 2004 Johnson 115 V4 running problems

So i managed enough time after work today to get the top starboard carb off and apart and staring me in the face was a small piece of what looks like blue plastic (see pics) stuck in the little brass tube that extends down into the bowl (that's a pin head next to the plastic for reference).

View attachment 161618
View attachment 161619

I think this tube is either the idle or mid-range fuel supply tube? Can someone verify for me?

Either way, I suspect this is probably some or all of my problem. I know those tubes were clear when I just rebuilt the carbs which makes me think the plastic must have come from inside the fuel system somewhere; does anyone know of anything in the vapor separator or OMS pump that is that color (diaphragm, etc)?

 

[woody66912]

Re: 2004 Johnson 115 V4 running problems

Bummer dude. The att is not showing up. Keep trying we need to see this.

 

[Chris1956]

Re: 2004 Johnson 115 V4 running problems

You might make sure fuel is being supplied to the upper carbs, while the motor is running. Pull the main jet covers and make sure it pours out, showing the fuel pump is working and the float is behaving itself.

 

[rkdygert]

Re: 2004 Johnson 115 V4 running problems

Here's those pictures again:

http://img20.imageshack.us/img20/6100/photo1zi.jpg
http://img717.imageshack.us/img717/2985/photo3zy.jpg

I got the other three carbs off tonight, no crap found in them. Also took the OMS pump apart, no plastic in there that matches what I found in the first carb...did find that the air diaphragm is starting to split through the first layer of rubber. Don't think this was causing the problems as the diaphragm isn't split all the way through but I guess it's a good time to replace it!

Still looking for answers...

 

[woody66912]

Re: 2004 Johnson 115 V4 running problems

I have never seen that part in a 60* fuel system. I would re-assemble and try it see what happens. It almost looks like someone has tried some type of repair, or trying to plug something off?.

 

[rkdygert]

Re: 2004 Johnson 115 V4 running problems

I disassembled all of the other fuel components now to check them and found no signs of damage or anything that looks like something that piece of plastic would have come from. I agree, have to put it back together and try...I'll keep everyone posted.

Thanks.

 

[toaster122002]

Re: 2004 Johnson 115 V4 running problems

There is a temperature sensor that when activated shuts down a couple of cylinders. (Lets you get back to the dock under partial power). I've read on other websites owners had a problem with this sensor going bad. After replacement of sensor, all was well. Not sure where its at. Have to do your own research.

 

[rkdygert]

Re: 2004 Johnson 115 V4 running problems

Thanks for the idea...I've checked both temp sensors and they are working fine, also have run the S.L.O.W. system checks to be sure it's not going into SLOW on me. Ignition seems strong, spark jumps 7/16" gap, and compression is 120-122# each cylinder...definitely seems to be some type of fuel delivery problem. I've read about 100 threads on this and other forums and can't even count how many times i've read other people's symptoms and said "that must be it!" only to be disappointed when I get to the dock to try it...