Johnson 140hp V-4 140ML77S Stuck at 2200 RPM

[gholmesjr]

We bought a boat recently. Ran great at the test run with the previous owner. Get it out Saturday runs great. Get it out Sunday and go to get up to speed (runs around 40mph) and can't get above 2200 rpms, about 5-7 minutes of running WOT at 2200 rpms and then it opens up finally and get up to about 35mph with four people on board and high chop, I figured that was pretty good. Get to the side of the lake to get the tube out and can't get it above 2200 rpms. Try and tool around a bit to get it up to plane and nothing. We get over to the shallows to at least be able to swim and I notice that a lot of fuel is spilling out into the water. We also has a full tank on the boat (15 gal) and was down half a tank in just that little bit. Turn the motor off and couldn't get it started for a bit (probably flooded). Get it home and pull the plugs. All are a little dark, but only one was wet. Thinking coil perhaps? Anyone have some ideas?

 

[1983 ercoa 21']

Check spark by seeing if it will jump a 7/16 gap

if you have week spark on one side but not the other would hint power pack if your motor has a power pack on each side you can swap side and see if the problem follows if so replace power pack.

you can also move coils if it's just one cylinder that has weak spark to see if it follows.

 

[emdsapmgr]

Checking plugs for differences is a good idea. Tells you something. Perhaps the wet plug is not firing. Best to decide just where that fuel leak is. From a carb, the fuel hose connection, fuel pump, loose hoses? None of the original 77 hoses are rated to handle today's ethanol fuels. They will break down and can leak-worse, the black bits of hose can loosen, then migrate down into the carbs, causing restrictions, etc. If they seem to be original-consider replacing them. Coils can fail, but they are usually one of the more robust ignition components. You've got others which are usually more troublesome: the single power pack, timer base and the stator.

 

[gholmesjr]

The guy I got the boat from said that the hoses have been replaced. From the looks of things I believe him. He said that they had the motor rebuilt last year. Is there a way to test the coils?

 

[1983 ercoa 21']

You can trade places with a known good coil and see if problem follows.

 

[gholmesjr]

I'll give that a shot. I've never had a motor that couldn't go above 2200 and then after a few minutes it kicked in all of a sudden. That's what puzzles me.

 

[jakedaawg]

Sounds like a stuck open float possibly. Does the bulb get firm when you squeeze it?

 

[gholmesjr]

Yeah it does. Well it did on Saturday. Sunday it wasn't as firm as it had been. Keep in mind I haven't had this motor very long, so hard to say how it normally is.

 

[gholmesjr]

I just went out and pressed the bulb. Can't really get it firm. Not like it was.

 

[1983 ercoa 21']

Take the front of the air silencer off tilt motor up just enough that fuel will run out the front and not into motor then pump bulb and see if fuel comes out of one of the carbs.

 

[jakedaawg]

Take a fuel sample while your at it. Sounds like you will be placing floats, needles and seats.

 

[emdsapmgr]

A normal fuel hose bulb will get hard when you first pump it up for the first start of the day. Once the engine is running and it starts flowing fuel through the hose, the bulb will soften, but should not collapse on itself. That's normal. If you do re-prime it later in the day, the bulb should pump up (firm) till it starts running again. When the engine limits itself to 2000 rpm's best to check for spark on all 4 plugwires. You may be losing spark to one or two cyls.

 

[gholmesjr]

So question. Does this motor rely on a battery to continue good operation? The reason I ask is the way the boat is setup, the motor battery and the trolling battery are connected together. I ran the trolling motor until it wouldn't run any longer. I noticed the motor's battery also drained quite a bit as I was unable to tilt/trim. I know on my old Mercury, that you could technically take the motor off the battery once it was running and it would sustain itself via the stator. However I am unaware if this motor does the same thing. Perhaps there wasn't enough juice to produce an adequate spark until the motor battery was charged via the stator thus kicking in the other cylinders? Seems like something that could be legit.

Thanks,

J.T.

 

[jakedaawg]

So question. Does this motor rely on a battery to continue good operation? The reason I ask is the way the boat is setup, the motor battery and the trolling battery are connected together. I ran the trolling motor until it wouldn't run any longer. I noticed the motor's battery also drained quite a bit as I was unable to tilt/trim. I know on my old Mercury, that you could technically take the motor off the battery once it was running and it would sustain itself via the stator. However I am unaware if this motor does the same thing. Perhaps there wasn't enough juice to produce an adequate spark until the motor battery was charged via the stator thus kicking in the other cylinders? Seems like something that could be legit.

Thanks,

J.T.

not the problem. Really think you have a stuck open float flooding out two cylinders.

 

[gholmesjr]

Reviving this old thread. New year, better results, but still hard starting. So I took the boat into the shop for a check up this year in April. Wasn't getting spark to two cylinders. Ended up replacing the trigger. Get the boat out and try to start, see fuel in the water again (we did not rebuild the carbs, costs were mounting). Finally got her started and she wouldn't go past 2500. Shut her down for a bit. Move a person to the front, hard start again, but she gets going. No hole shot possible, but did get her up to 6500 RPM and on plane. Have no power for the initial 2500 rpms but then slowly she will get up to speed.

I wanted to get to carbs rebuilt, but the shop I take it to was unable to since the guy that specializes on the older Johnsons just had a baby with his wife on Wednesday so he is out and I am leaving for vacation tonight. I am thinking of rebuilding the carbs when I get back.

Is there a link & sync procedure with these old Johnsons? The Merc 115 I had before this one was a PITA to link and sync and I don't want to go through the trouble of doing the carbs if I can't get the timing right.

Thanks,

J.T.

 

[racerone]

Go for doing this yourself.-----Nothing to it.-------Fact----The battery and 12 volts are not used to fire the sparkplugs on this motor.

 

[gholmesjr]

Thanks Racerone. I can't imagine that this is more difficult than the Merc I worked on. I did find these instructions for the link & sync.

For what it's worth, here's what Joe Reeves had to say about Link & Sync on 1977 140 HP from an old post:

JOE REEVES 1977 evinrude 140 engine synchronization and linkage adj.
1 - Make sure that the throttle butterfly linkage between the two carburetors is adjusted so that the butterflies open and close at the same time. You DO NOT want the linkage adjusted so that at a dead idle, one butterfly is close and one is slightly open.
2 - Set the throttle butterfly cam roller so that the cam scribe mark touches the cam roller dead center, not before or after. The throttle butterflies should just start to open when the cam scribe mark hits the center of that roller.
3 - Set the idle timing with a timing light to whatever it states in your manual (probably between 3 to 5 degrees but check it). whatever the idle timing is, it should be set to that degree when the cam scribe mark is dead center with the cam roller. Adjust the linkage between the cam and the vertical throttle arm as needed.
That's it.

You think this is still valid for what I am going to do. My plan is to take the carbs off, get a carb kit for each. Install them and follow the instructions for the sync. Seems pretty simple. Would I even need to do a sync if I don't touch the linkage settings?

 

[gholmesjr]

So I got home from vacation and went to diagnose things. I pumped the bulb and fuel came through to the carbs. The bulb doesn't stay 100% hard, but I can't depress it all the way either. I took the air silencer off and tilted the motor up to see if fuel will leak out of the carbs, they do not leak. The carb seals look to be new. I hit the choke and started her and then fuel leaked out of the front. I think this is normal with choking a carb. It started up after a couple of cranks. I am thinking of taking it to the lake tomorrow to diagnose a bit more. Could the timing be off and so in the water it won't run as well under pressure? I am going to check for spark even though the shop said that they replaced the trigger and that it was getting good spark. Any other suggestions on what to look for?

 

[racerone]

A sheared flywheel key changes the timing.----Other than that the timing is set at the factory and it does NOT go out of adjustment for the life of the engine.

 

[gholmesjr]

The shop put a new trigger on and so would have to take the flywheel off, I would think they would have found a sheared key. I have a couple of videos of the motor running. Sounds like it is missing a lil.

Also the number 2 and number 3 cyclist areally a little wet on the spark plug.