77-78 Evinrude 140 runs rough

[CynicalOne]

Here's what I have -

Bought a 85 Ranger 340 V with an apparent 115 Evinrude. The guy I got it from said it ran fine up to about 3/4 throttle but would die at WOT. Said he rebuilt the carbs and put a 12psi electric fuel pump on it and it still would die at WOT. I verified that it WOULD run before I bought it and since I was getting the whole package for near nothing, I figured even if I had to tinker with the motor I could still be ok.

What I found out after I got it home is that it wasn't the engine he thought it was. The button on top says 140883c which means it's a 78 140 not a 115. So from there I first ordered the proper manual fuel pump (knew the electric was a no-no) and a set of carb kits going by that model #. Rebuit the carbs, installed the pump and it started on muffs within minutes... GREAT! Took it to the river, started and warmed up fine ( a little cold) and took it out to she what she would do. On the way out, it died a couple times and I noticed the primer bulb was flat. Back to the dock and replaced the bulb. Back out ran fine. Opened it up and I was happy... up and on plane fast. Tried this several times and was content. As this was just a test run, I headed back to the dock. Pushed it forward, planed out.... and died. Restarted after a couple of attempts, pushed forward, planed out... and died. Did this 3-4 times back to the dock, but seemed to run fine at lower revs.

It was suggested that the power packs may be getting hot and killing fire at WOT, so I ordered 2 new ones going with the #140883c. Received those... and they're wrong. Actually before I got them, I discovered they were wrong. Looking at my ignition and with some digging, my ignition is from a 77 with a SINGLE power pack. Maybe this engine was an EARLY 78 model? Either way, got the right power pack replaced and took it back to the river. Again, the primer bulb would go flat. Since it was new, I knew there had to be a restriction to the tank. Worked it out and pushed it forward... planed out and... died. Different this time as it seemed more like it ran out of fuel than just died. Back home and replaced fuel lines from bulb to tank, installed new filter and pumped it up. As the fuel hit the filter I saw it fill with trash. New line, so it had to be coming from the tank. In short, I removed and cleaned the tank, new fuel... new filter. Back to the river and the 'dying' is gone. But it runs like crap. Top RPM is at WOT is 3800. Read in the manual this should be about 4500+. Engine misses thru all ranges and sometimes stumbles and dies at idle on muffs.

So here's the list of things done -

New fuel pump

New lines and tank cleaned - Found a couple foil seals from oil bottles in tank. This was my restriction

Carbs cleaned and rebuilt

New power pack - but it runs the same with the one I replaced

Checked and verified all wiring is correct per manual

Using inline tester verified spark on all Cylinders

Compression is 120, 120, 120, 110

Did a 'link-n-sync' per manual

Engine starts fairly easy when cold and will start instantly when warm.

Runs rough thru ALL RPMs - Missing, coughing, choking, sneezing... whatever you want to call it.

I'm stumped... HELP??

 

[CynicalOne]

Re: 77-78 Evinrude 140 runs rough

Also, I don't have a DVA but I did a few tests with a digital multi-meter on the sensor leads to the stator. It 'seems' to be ok. BUT.... I'm not 100% sure I did the tests right.

Also ran the engine in total darkness and didn't see and lines arcing.

 

[fireman57]

Re: 77-78 Evinrude 140 runs rough

If your primer bulb is still going flat make sure that your tank is vented. Sounds like a fuel restriction at this point. Try the simple things first.

 

[CynicalOne]

Re: 77-78 Evinrude 140 runs rough

I'm sorry, I didn't state that the primer bulb is now fine and works as it should. The fuel restriction was cleared up when I removed and cleaned the tank. With the tank cleaned, all new lines and filter I'm not seeing where there could be another restriction. It's a built in tank and the fill and vent tubes have both been replaced as well.

 

[fireman57]

Re: 77-78 Evinrude 140 runs rough

I would go back through my carbs as your spark situation checks out. Also make sure that your timer base isn't sticking as you give it throttle

 

[CynicalOne]

Re: 77-78 Evinrude 140 runs rough

Thanks, Fireman.

Going back thru the carbs is my next step along with putting in a water/fuel separator. Runs the same on a test tank, so the latter is just for future possibilities.

The Timer base does indeed advance as it should and moves freely by hand with the engine off. I have a guy with a DVA that has offered to test everything properly, but I work later than he does and can't seem to get by there.

I just keep thinking it's going to be something simple as it didn't run rough before I replaced all the lines and cleaned the tank.

 

[fireman57]

Re: 77-78 Evinrude 140 runs rough

It usually is something simple that is why I suggested what I have. If you don't have a fuel filter/seperator inline put that in before you start it up after checking your carbs again. It's amazing the stuff that gets in a gas tank.

 

[emdsapmgr]

Re: 77-78 Evinrude 140 runs rough

Check the ball valve in the anti-siphon valve on the tank. If it gets any "grit" or debris in it, it won't function properly. It could jam partially open, causing insufficient fuel to reach the engine. Check for spark on all 4 cyls when it starts to act up. Either a spark-checker or an inductive timing light. Either will show the quality of spark. Make sure the engine is well warmed up before you check for spark.

 

[CynicalOne]

Re: 77-78 Evinrude 140 runs rough

There's no anti-siphon on the pickup. Tank has been cleaned and everything from tank to engine is new. The only place left for any trash is in the carbs which I plan to clean again today. This would be only because I haven't cleaned them since replacing everything.

Using an inline spark tester, the spark is good on all cylinders. Only drawback from this is that I can only check one at a time. I don't know if it's missing on one cylinder, or intermittenly on more than one or all four.

 

[CynicalOne]

Re: 77-78 Evinrude 140 runs rough

I cleaned the carbs... AGAIN, and the symptoms are still there. It runs fine, then stumbles. Sometimes to the point of dying at idle. I uploaded a video to YouTube where you can see what I mean. You may have to turn the volume up a bit, but listen at about 4-5 sec and around the 15 and 27 second marks.

https://www.youtube.com/watch?v=3b_wxJF_Ets&feature=youtube_gdata_player

 

[fireman57]

Re: 77-78 Evinrude 140 runs rough

Are you sure that your primer solenoid isn't turned the wrong way or your choke is getting stuck? All butterflies open at the same time and the same level? run with the cover off and have a buddy visually make sure that your timer base is getting it's full movement when you throttle up. Since the engine isn't what he thought it was is it possible he put 115hp carbs on a 140?

 

[CynicalOne]

Re: 77-78 Evinrude 140 runs rough

I had thought of that... about the carbs maybe being different. BUT, the only difference in the 115 and 140 for both 77 and 78 model years are the jets. Only other difference they could have is either electric or manual choke. Mine has electric choke mounted on the silencer indicating it's a 78 as the 77 had the electric choke mounted on the intake.

All butterflies open as they should as far as I can tell and the timer is working freely. But, I wouldn't think that would make it run the way it does at idle... since nothing is being moved? It runs the same from idle to WOT in both forward and reverse.... like it's missing or has bad gas.

One thing puzzling me is that when I first got it and it died, it didn't run rough. Changed the power pack, still died but didn't run rough. Replaced all the fuel lines, cleaned the tank, new filter, new gas and recleaned the carbs... and runs rough but don't die out @ WOT. Mix is 50:1 with premium TCW-3 oil and non-ethanol fuel. What am I missing?

BTW, It doesn't have a primer solenoid.

 

[emdsapmgr]

Re: 77-78 Evinrude 140 runs rough

Your video is password protected. Can you open it up for general viewing? Your engine should at least run with 115 carbs on it, just won't make hp. That engine does not have a fuel primer solenoid, it's a choke solenoid. It's possible some of the debris from the fuel line is lodged under the core plugs in the upper carb body. Have you had them out during your previous cleanings?

 

[fireman57]

Re: 77-78 Evinrude 140 runs rough

If it is running rough all the way through it is either missing on a cylinder or fuel problem. If you have fresh fuel that can't be it. If you have a timing light you can use it to check spark while you are running (with a buddy of course and stopping each time he has to put it on a different plug wire).
If the jets are different that will make a difference if they are smaller the engine will starve and too big and it will flood.

You might want to have your buddy squeeze the primer bulb while you are running. I know you put a new fuel pump on it but it doesn't hurt to give it a quick test.

 

[fireman57]

Re: 77-78 Evinrude 140 runs rough

If it is running rough all the way through it is either missing on a cylinder or fuel problem. If you have fresh fuel that can't be it. If you have a timing light you can use it to check spark while you are running (with a buddy of course and stopping each time he has to put it on a different plug wire).
If the jets are different that will make a difference if they are smaller the engine will starve and too big and it will flood.

You might want to have your buddy squeeze the primer bulb while you are running. I know you put a new fuel pump on it but it doesn't hurt to give it a quick test.

 

[CynicalOne]

Re: 77-78 Evinrude 140 runs rough

I've used an inline tester and verified that I have spark on all four, but there's no way to actually identify a miss, or the strength of the spark for that matter. Pulled all 4 coils and cleaned the contacts making sure they were good.

I've pumped the bulb myself at idle and it doesn't seem to make a difference.

3 things I'm not able to check with accuracy are the stator, timer and flywheel magnets. Well, I could check the magnets by pulling the wheel... but not yet.

 

[CynicalOne]

Re: 77-78 Evinrude 140 runs rough

I've changed the video to public twice. Maybe this time it took.

Core plugs. No, I haven't had those out but I blew the passage out with both carb cleaner and air. But, as you say, debris could've lodged in there and resist coming out without plug removal.

 

[fireman57]

Re: 77-78 Evinrude 140 runs rough

When you cleaned the carbs did you use a very small strand of wire and run it through all the jets and pickup tubes and holes?

 

[fireman57]

Re: 77-78 Evinrude 140 runs rough

You have a pm

 

[CynicalOne]

Re: 77-78 Evinrude 140 runs rough

Here's the video