Help troubleshooting, sputtering V4 Johnson

[mfsb]

Hello everyone. I have thoroughly enjoyed this forum so far and looking for help. I am troubleshooting my V4 Johnson 140 hp. Ser. No. J140txco . It is a 1985 2 stroke V4. I have recently been working on several kinks as I prepare it for sale or use this spring. I have a problem with it sputtering and now not able to get above 2500 rpm's. I believe it is a set of dirty carbs and will be cleaning and resealing them, including the base plates. If anyone has any other recommendations I would greatly appreciate it. The previous owner bypassed the VRO system and I mix 50:1 in the tank when filling. I have removed the anti-siphon valve and installed a fuel water separator. I installed a new filter element, new plugs, fresh fuel, sea foam with fuel, and lower unit. I have a 15 x 17 prop on the boat.

The boat is not the best starting, but not difficult. I have to advance the throttle a bit to get it to fire up, but once it fires it runs and does this reliably. Once idling it stumbles a bit roughly every 30 seconds it sneezes, and won't accelerate over 2500 rpm. If you go to max throttle it bogs down the dies. You can sometimes catch it and keep it running, but often it just dies and you have to restart. When you do restart it takes a couple tries of bumping the starter but will always restart.

Again, I believe I have some dirty carbs and will be cleaning them. I am open to other suggestions though and appreciate any advice.

tried to upload video taken by my iphone, but it won't upload. not sure what to do. Description is pretty accurate though.

 

[Bosunsmate]

Re: Help troubleshooting, sputtering V4 Johnson

A thorough carbs clean may fix all that. Make sure you check every passage is clear, spray fluid through them and check it comes out somewhere easily.
Always good to do a spark test on these as with four cylinders its often not obvious that one cylinder isnt firing until you put it under load

 

[Bosunsmate]

Re: Help troubleshooting, sputtering V4 Johnson

If you look at your spark plugs you might see that there is a difference in a plug colour that will help pinpoint the problem, but id still clean all carbs anyway

 

[mfsb]

Re: Help troubleshooting, sputtering V4 Johnson

yeah I am going to pull them out and do a compression check as soon as I can get my hands on a good gauge. I am concerned the motor just may be done. I am not so sure I want to go through the trouble of rebuilding it or continuing to put a bunch of money into it. We will see. First a good compression check, and verify all the spark plugs, and good spark at each plug. Who knows, it will hopefully be a simple fix, or at least an inexpensive one.

 

[mfsb]

Re: Help troubleshooting, sputtering V4 Johnson

Well I did a compression check and was anxious about the results. I had 130 at the very top end and 121 at the low end on numbers. All plugs had black residue on them, as if it was incomplete combustion. Could a bad timing base be my problem not the carbs?

 

[V153]

Re: Help troubleshooting, sputtering V4 Johnson

That compression ain't so bad. Seen much worse ...

I'd clean/rebuild the carbs for starters. See what happens.

Double check the VRO 'bypass' procedure too.

 

[V153]

Re: Help troubleshooting, sputtering V4 Johnson

Sounds to me like ya got some crud stuck in a high speed jet.

 

[racerone]

Re: Help troubleshooting, sputtering V4 Johnson

Use a timing light on each cylinder and observe the flashing light.--------If it is not a steady flash on all four as u wind it up there are ignition problems.

 

[V153]

Re: Help troubleshooting, sputtering V4 Johnson

Could be wrong but fwiw I doubt it's an ignition or timing problem.

 

[mfsb]

Re: Help troubleshooting, sputtering V4 Johnson

I checked timing light response from each cylinder after replacing the spark plugs from the compression check. It still runs up to and stops at 2500 ish and no high under load. I am pretty sure that I am still stuck on a fuel delivery issue. I will be taking the carbs off when I get the chance and update when that happens. I plan on doing the complete, carbs and base cleaning. So it will take me a while. Probably first of next month at the earliest due to work. Thanks for all the help, I will post as soon as I get the carbs off.

 

[mfsb]

Re: Help troubleshooting, sputtering V4 Johnson

I pulled the float drain off, high speed jets on all carbs and replaced two with two from spares I had in the garage. Same problem. I put fresh clean gas in, removed the anti syphon valve and have recently replaced the squeeze bulb with a new one. I have a fuel water separator installed with a fresh filter. I will be ordering a set of carb kits, bad gaskets, and frost plugs to thoroughly clean the carbs and bases. Is there anything else? I am really thinking it is ignition. Also after running and troubleshooting I noticed the port bank of cylinders are significantly warmer to the touch than starboard.

 

[racerone]

Re: Help troubleshooting, sputtering V4 Johnson

Last one I saw with cold head on one side was the owner putting plug wires on wrong.-------------------So check that out.--------The wee orange wires are usually orange / blue for the top ( sky ) and orange / green bottom ( grass )---Also might check thermostat if it not the wiring issue.

 

[mfsb]

Re: Help troubleshooting, sputtering V4 Johnson

UPDATE!, so I have done a bit of looking and was thinking that my ignition system was suspect as well. I swapped the Stator and trigger with new parts. I had a used trigger in there and I was not confident in it at all...... Of course it isn't fixed, but it is running much smoother at the rpm range it does run at. I ran it just a few minutes ago and while squeezing the bulb the VRO fuel pump leaked fuel at the vacuum port, so I think the fuel pump is giving me some problems as well. I think I will pick up a new one, found one on EBAY someone bought and didn't need for 175. I also ordered carb kits and base gaskets for pulling, cleaning, and re-install the carbs. I hope with all this it works, I also will be replacing all the fuel line, hope somewhere I fix all this. I will put the pump on first, hoping it is the fix and I can wait till next winter to pull the carbs.

 

[mfsb]

Re: Help troubleshooting, sputtering V4 Johnson

UPDATE, I have received my carb kits, and a brand new VRO pump. I wasn't sure the pump was the problem, but at this point I felt it was worth replacing. Of course, I ran it with replacing the pump and it didn't fix it. While tearing down the carbs today I noticed that there is a difference in the two carb base plates. I am not sure this has a major effect, but I felt it could be the source of my issues, so I am replacing them with some from ebay. . I am not sure if the difference between the two sides would produce an unbalanced engine. Maybe this would cause my problems, not sure. Either way it doesn't seem right so I am changing to a matched set.

 

[mfsb]

Re: Help troubleshooting, sputtering V4 Johnson

So I am updating this post. I am still having problems and I am not sure what to do next. I have replaced the following and am tired of throwing money at this. I don't believe that it is a part, maybe a procedure at this point.

I have replaced the following:
Stator
Trigger Base
Carburetors
Fuel Pump
Spark Plugs
Thermostats
Cylinder Head

I do have good compression on all 4 holes 130 max, 120 min. I have used an inductive light to check for spark on each hole. The carburetors have been cleaned and new fuel lines from the fuel pump to the carbs, new fuel manifold. I have replaced the fuel squeeze bulb earlier this year. The carbs were used and need to be sync'ed. The engine acts like it is running out of fuel if I advance the throttle to mid rpm, about 3k to 4k. If I push it to wide open it will run, but not super strong. I am thinking maybe the base could be out of time. So one of the first things I need to do is clean the carbs the best I can, but timing the engine then what??? Please help.

 

[Bosunsmate]

Re: Help troubleshooting, sputtering V4 Johnson

Whats the timing at when at wot?
You dont need to have it running to see that
Put a dollar bill over all carbs and check they are sucking

 

[Triangleboater]

Re: Help troubleshooting, sputtering V4 Johnson

When you say you cleaned the carbs, what exactly did you do? I have seen so many times that people clean them, just not good enough. I always do two things. First run a small wire through all the passages, then spray with carb cleaner. I then blow them all out with compressed air. And repeat the carb cleaner compressed air a few times. Also make sure you get EVERYWHERE. It should take a while if doing it. For my older johnson with one carb, the job took me 30 mins or so, that was just the cleaning.

 

[mfsb]

Re: Help troubleshooting, sputtering V4 Johnson

I have the manual in front of me, I see the link and sync procedures. I have adjusted the throttle bodies and they now open full ways and close. I am still at a loss however on ignition timing and how to set it properly. I see where the stop is adjustable, and the throttle arm adjustment is, just don't see how to set it to base timing. I have a timing light and I am ready to try it, I just am not sure where to set the base timing at.I think the one side of the motor still having temp differences is a symptom of what ever is going on with this motor.I think if I can identify what is causing that it will fix everything. I have replaced the thermostats and that side head. I had a problem with corrosion on that thermostat housing and it was a lost cause, so I picked one up from the net. I first thought bad head gasket with the new one, but the compression numbers are great.